Department: Food Science and Technology ![[clear]](close-x.png "Remove this limiter")
55 matches in the database.
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1.
Agila, Amal.
Volatile Profile of Cashews (Anacardium occidentale L.), Almonds, and Honeys from Different Origins by Selected Ion Flow Tube Mass Spectrometry.
Degree: PhD, Food Science and Technology, 2012, Ohio State University
► Volatile compounds were quantified in the headspace of Indian, Vietnamese and Brazilian…
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▼ Volatile compounds were quantified in the headspace of Indian, Vietnamese and Brazilian cashews, both raw and during roasting by Selected Ion Flow Tube-Mass Spectrometry (SIFT-MS). Raw cashews were oil roasted for 3 to 9 min at 143 ºC and color and volatiles measured. An excellent correlation, following a pseudo-first order reaction, was found between L value and roasting time; darkness increases as roasting time increases. The optimum roasting time was 6, 8 and 9 min for Vietnamese, Indian and Brazilian cashews, respectively. Raw cashews had lower concentrations of volatiles than roasted cashews. Most volatiles significantly increased in concentration during roasting of Brazilian, Indian and Vietnamese cashews. Brazilian cashews had significantly higher levels of most volatiles than Indian and Vietnamese cashews. Of the volatiles, methylbutanal, 2-methylpropanal and acetaldehyde were at the highest concentration in roasted cashews. The Maillard reaction contributed to the formation of the most of the volatiles in the cashews from the three countries. Raw pasteurized almonds were roasted in a microwave for 1 to 3 min, in an oven at 177 ºC for 5, 10, 15, and 20 min; and at 135 and 163 ºC for 20 min, and in oil at 135, 163, and 177 ºC for 5 min and 177 ºC for 10 min. Volatile compounds were quantified in the headspace of ground almonds, both raw and roasted, by Selected Ion Flow Tube-Mass Spectrometry (SIFT-MS). Strong correlations were found between L value, chroma, and 5-hydroxymethyl furfural (HMF). Raw almonds had lower concentrations of most volatiles than roasted almonds. Conditions that produced color equivalent to the commercial samples were 2 min in the microwave, 5 min at 177 ºC in the oven, and 5 min at 135 ºC in oil. Microwave heating produced higher levels of most volatiles than oven and oil roasting at commercial color. Sensory evaluation indicated microwave-roasted almonds had the strongest aroma and were the most preferred. Oil-roasted almonds showed significantly lower levels of the volatiles than other methods. The Maillard reaction contributed to the formation of more of the total volatiles in almonds than the lipid oxidation reaction. Ten Ohio and Indiana honey samples from star thistle, blueberry, clover, cranberry, wildflower, and an unknown source were collected. The headspace of these honeys was analyzed by selected ion flow tube mass spectrometry (SIFT-MS) and soft independent modeling of class analogy (SIMCA). Ohio honeys from star thistle, blueberry, and clover were similar to each other in volatile composition, while Ohio wildflower honey was different. Indiana honeys from star thistle, blueberry, and wildflower were different from each other in volatile composition while clover and cranberry honeys were similar. Honeys from Ohio and Indiana with the same floral origins were different in volatile composition. Furfural, 1-octen-3-ol, butanoic and pentanoic acids were the volatiles with the highest discriminating power between types of floral honey. The highest concentration of volatile compounds was in Indiana wildflower honey followed by Ohio wildflower honey while the lowest concentration of volatile compounds was observed in Ohio clover honey followed by Indiana clover honey.
Advisors/Committee Members: Barringer, Sheryl A.
Subjects: Food Science
Keywords: Maillard reaction; optimum roasting time; HMF; floral origins; geographical locations
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2.
Ahmadiani, Neda.
Anthocyanin Based Blue Colorants.
Degree: MS, Food Science and Technology, 2012, Ohio State University
► Anthocyanins are a group of natural pigments extensively found in nature. Two…
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▼ Anthocyanins are a group of natural pigments extensively found in nature. Two main functions of these compounds are their ability to elicit different colors and to impart health benefits. Color is an essential part of the identity of foods and can affect the products’ success in the market. The food industry is searching for natural alternatives to the use of synthetic dyes. A particularly difficult challenge has been finding a natural blue that can replace synthetic FD & C Blue colorants. Some anthocyanins, under neutral to alkaline conditions can turn blue; however, the shades and stability of the blue color highly depends on the source. The aim of this study was to identify and increase our understanding of anthocyanin-based blue colorants from edible materials that can closely match the color characteristics of synthetic FD & C Blue colorants. To achieve this objective, anthocyanins from edible materials as well as commercial extracts were evaluated in regards to color and stability under a wide range of pH. Antocyanins from Baby Indian, Italian, and American eggplant, known to be delphinidin derivatives, were extracted. Delphinidin has three hydroxyl groups on its B-ring expected to cause a bathochromic shift and yield a blue hue. Eggplant anthocyanins were identified by HPLC-PDA, and quantified by the pH differential method. Color (CIELAB) of the extracts were measured after mixing with buffer with pH 3.5, 5, 6, 7, and 8. Monomeric anthocyanin content varied between 45-83 mg Dp-3-glu /100g skin. The major anthocyanin present was Dp 3-rutinoside. The color of the pigments were red at pH 3.5 with L*, c, and h° values of 79.42, 25.28, and 29.21° respectively; however, at pH 8, these values changed to 70.83, 10.8, and 96.97°respectively corresponding to a yellow hue. Anthocyanins from eggplant did not produce blue color perhaps due to lack of acylation. Acylated cyanidin-derivatives were then explored as possible sources of natural blue colors, and compared to sources with different anthocyanin patterns.Commercial extracts of red cabbage (RC), purple sweet potato (PSP), black carrot (BC), red radish (RR), purple corn (PC), and grape (GE) were mixed with 0.01M potassium phosphate buffer (1:5, v:v) at pH 6, 7 and 8. UV/Vis spectra (400-700nm) and CIELAB values were obtained after 15-20min equilibration and over 20 hours refrigerated storage. HPLC-PDA-MS was used to identify the major anthocyanins in each extract. Highly acylated cyanidin-derivatives were the major pigments in RC, PSP, and BC. Acylated peonidin-derivatives were also abundant in PSP. PC contained ~40% acylated-cyanidin. Acylated pelargonidin-derivatives were predominant in RR. GE contained acylated and non-acylated malvidin, petunidin, delphinidn, and peonidin. RC and PSP produced blue hue (similar to FD & C Blue No.2) with h° and lambda max of 233°, 612nm and 264°, 605nm respectively at pH 8. The stability of RC, however, was significantly higher than PSP over 20hr refrigeration. The substitution of the B-ring with two hydroxyl or methoxyl groups and acylation with aromatic acids seemed to be critical for the production of blue colors from anthocyanin-rich sources.
Advisors/Committee Members: Giusti, Monica.
Subjects: Food Science
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3.
Allendorf, Meghan E.
Application of a Handheld Portable Infrared Sensor to Monitor Oil Quality.
Degree: MS, Food Science and Technology, 2010, Ohio State University
► Advances in infrared technology have made it a promising method for the…
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▼ Advances in infrared technology have made it a promising method for the food industry. The development of the Fourier Transform (FT) algorithm has shortened scan time, improved signal-to-noise ratio, and improved the accuracy of wavelength. Innovations in personal computing has made FT-infrared (FTIR) spectroscopy common place in quality control labs. Analysts routinely combine FTIR spectra with multivariate analysis to quantify components in their matrix. Food scientists have combined FTIR with chemometrics to detect adulteration in their products. Both near- (NIR) and mid- (MIR) infrared have proven to be valuable resources for rapidly authenticating the quality of food. NIR has been applied to products such as juice, honey and milk, and for detecting acrylamide in potato chips. MIR has been successful in authenticating edible oils, juices, honeys, and for ensuring products are correctly identified as organic. As food safety continues to be a top priority for consumers, there is no doubt that improvements will continue to be made on spectrometers and in chemometric methods in order to stay one step ahead of adulterators. One such improvement has been the development of handheld portable infrared sensors. These units are used for chemical identification in the homeland security, public safety, pharmaceutical, industrial, and medical markets. They bring the spectral resolution of benchtop instruments to field applications in rugged, battery operated units weighing less than four pounds. A novel application of a handheld FTIR is for monitoring oxidation in edible oils. Methods currently used for oil quality testing are subjective, time consuming, and use hazardous solvents which then need to be disposed of. The aim of this research was to evaluate the capabilities of a handheld FTIR combined with multivariate analysis to characterize frying oils and to monitor chemical processes occurring during lipid oxidation as well as determining fatty acid composition. Commercial frying oils (corn, peanut, sunflower, safflower, cottonseed and canola) were heated to 65°C in an oven for thirty days to accelerate oxidation. Reference methods included fatty acid composition (IUPAC 2301, 2302), peroxide values (PV, AOCS Cd 8-53) and free fatty acid (FFA, Shipe 1979). Aliquots were drawn at five day intervals and analyzed by benchtop and handheld mid-infrared devices and reference methods. Spectral analysis (Soft Independent Model of Class Analogy (SIMCA) and Partial Least Squares Regression (PLSR)) was carried out by pattern recognition software. Mid-infrared spectral regions ~3000-2825 cm-1 (C-H stretching bands) and 1740 cm-1 (C=O stretching of esters) were important for classification. All six oil samples formed distinct and well-separated clusters in the SIMCA plot due to difference in their chemical composition. It was found that spectral variability could be minimized by controlling oil temperature (65°C) during data acquisition. PLSR showed good correlation coefficients (Rval) between FFA and PV on the infrared devices. Handheld IR instruments combined with multivariate analysis showed promise for determination of oil quality parameters with similar performance as the benchtop units. Its portability and ease-of-use make the handheld IR a great alternative to traditional testing methods.
Advisors/Committee Members: Rodriguez-Saona, Luis.
Subjects: Food science
Keywords: edible oils, chemometrics, oxidation, infrared
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4.
Atnip, Allison A.
Oxidative Stabilities of Docosahexaenoic Acid Oil and Linoleic Acid in an Aqueous System.
Degree: MS, Food Science and Technology, 2010, Ohio State University
► Docosahexaenoic acid (DHA) has been shown to be essential for normal brain…
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▼ Docosahexaenoic acid (DHA) has been shown to be essential for normal brain and retinal development. Effects of refining, bleaching, winterizing, and deodorizing on the oxidative stability of DHA (22:6 Ω-3) oil were studied by a combination of headspace oxygen depletion (HOD) by gas chromatography and total volatile compound formation by SPME-GC. The oxygen content in the refined, bleached, winterized, and deodorized DHA oil samples decreased from 20.9% on Day 0 to 6.7%, 8.3%, 7.8% and 7.8%, respectively on Day 5. The bleached, winterized, and deodorized oils were determined not to be statistically different from each other (p > 0.05), however the refined oil showed significantly more HOD (p <0.05), corresponding to a lower oxidative stability. Refined, bleached, winterized, and deodorized oils showed average volatile compound formations over 5 days of storage of approximately 4,041,000 electronic counts (ec), 482,100 ec, 437,200 ec, and 405,800 ec, respectively. The refined samples again showed significantly (p < 0.05) higher volatile compound formation, corresponding to a lower oxidative stability. The bleached, winterized, and deodorized samples were not significantly different from each other (p > 0.05). Bleaching proved to be the crucial processing step in increasing the oxidative stability of DHA oil. Ginseng has been shown to be a natural antioxidant, and compounds from its extract are studied here for their individual antioxidant effects. Kaempferol, caffeic acid, ferulic acid, salicylic acid, and vanillic acid were previously isolated, separated, and identified by the combination of HPLC, NMR and MS. The effects of 100 ppm of each compound on the riboflavin photosensitized oxidation were studied at 4°C for 3 hours. Additionally, the effects of 100 ppm of each compound on the autoxidation of linoleic acid was studied, both with and without added ferrous chloride to give 2 ppm ferrous ion at 37°C in the dark for 10 days (with ferrous ion) or 40 days (without ferrous ion). The HOD of the samples was determined by GC and the peroxide value by spectrometry. Caffeic acid, kaempferol, vanillic acid, salicylic acid, α-tocopherol, and ferulic acid minimized the photosensitized oxidation by 37, 30, 30, 18, 17, and 0%, respectively. The average peroxide value for linoleic acid in aqueous solution without 2 ppm ferrous ion and 100 ppm kaempferol, vanillic acid, ferulic acid, caffeic acid, salicylic acid, α-tocopherol or control during 40 days of storage was 0.2, 0.7, 2.2, 2.3, 2.7, 2.8, or 3.7, respectively. The average peroxide value for samples with 2 ppm ferrous ion and 100 ppm kaempferol, vanillic acid, ferulic acid, caffeic acid, α-tocopherol, salicylic acid, or control during 10 days of storage was 0.3, 1.2, 2.5, 2.8, 5.3, 6.3, or 7.5, respectively. Ginseng compounds did not have antioxidant effects in the photosensitized oxidation of 2% linoleic acid in the aqueous system at p>0.05. Ginseng compounds except salicylic acid had better antioxidant effects than α-tocopherol in the autoxidation of linoleic acid in the aqueous system at p< 0.05. Caffeic acid, ferulic acid, and vanillic acid may act as antioxidants by the combination of donating hydrogen atom and chelating ferrous ion.
Advisors/Committee Members: Min, David.
Subjects: Chemistry; Food science
Keywords: docosahexaenoic acid; DHA processing; lipid oxidation; ginseng extract; chelating ability
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5.
Aykas, Didem P.
The Effect of Temperature, Lecithin Content, Voltage, Resistivity, Viscosity, and Surface Tension on Droplets/cm² During Electrostatic Spraying of Oil.
Degree: MS, Food Science and Technology, 2012, Ohio State University
► In the food industry it is important to evenly coat the surface…
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▼ In the food industry it is important to evenly coat the surface of food when oil soluble flavor, color or nutrients are added. Soybean oil was sprayed on oil sensitive paper at 4, 22 and 47°C, 0 to 40kV with 0 to 15% lecithin to determine droplet distribution. Lecithin decreased electrical resistivity, increased viscosity, and first increased then decreased surface tension. Increasing temperature decreased resistivity, viscosity, and surface tension. Increasing voltage decreased the drop size and increased the number of droplets. At 0 kV and 0% lecithin oil did not atomize therefore the drop sizes were significantly larger and the number of droplets/cm2 lower than with electrostatic atomization. 15kV was the threshold voltage for atomization. Increasing lecithin content up to 10% increased the number of droplets/cm2, while further lecithin addition increased, decreased, or had no effect. Increasing voltage and temperature, and decreasing resistivity, viscosity and surface tension produced a higher number of droplets/cm2. Voltage had the greatest effect on the number of droplets followed by lecithin content and temperature. The Weber number for the onset of droplet formation was determined to be 0.01. Droplet size range or span decreased with increasing voltage and lecithin content. Thus, higher voltage, higher temperatures, and 10% lecithin produced the lowest resistivity and the smallest droplets.
Advisors/Committee Members: Barringer, Sheryl A.
Subjects: Food Science
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6.
Berber, Murat.
Whey Protein Concentrate as a Substitute for Non-Fat Dry Milk in Yogurt.
Degree: MS, Food Science and Technology, 2010, Ohio State University
► Whey is a by-product liquid produced from cheese manufacturing. Whey used to…
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▼ Whey is a by-product liquid produced from cheese manufacturing. Whey used to be a waste product but its conversion through new technologies such as fractionation, modification, and filtration has made it possible to improve its utilization. Whey proteins have good nutritional properties and enhance the textural properties of food when they are used as ingredients. The objective of this study was to evaluate non-fat, low-fat and full-fat stirred style strawberry flavored yogurt formulated with whey protein concentrate 80 (WPC80) replacing non-fat dry milk. Levels of total solid were adjusted to 14.8%, 15.7%, and 17.3% for non-fat, low-fat and full-fat yogurts, respectively. Non-fat dry milk yogurt formulation was used as a control. Batches of 17 pounds of yogurts at 0% fat, 1% and 3.3% fat were made by mixing milk with powdered ingredients in a liquefier, homogenized at 2300psi, and pasteurized at 92°C for 30 seconds. Following cooling, yogurts were fermented at a final pH of 4.5. Yogurts were analyzed for their chemical and physical properties following the standard methods of analyses. Sensory evaluation was done by descriptive method with hedonic and monadic scales. Whey protein yogurts at all fat levels showed better water holding capacities (ca. 10%) than controls with increased hardness (ca. 20%) and viscosity (ca. 40%). Sensory results revealed that whey protein yogurts had higher flavor and overall liking scores than controls, while controls had better scores for the yogurts’ texture. Results showed that WPC80 is a good alternative to replace NFDM completely in yogurt. Whey yogurts had equal or greater quality than yogurt products made with NFDM.
Advisors/Committee Members: Alvarez, Valente.
Subjects: Food Science
Keywords: yogurt; non-fat dry milk; whey protein concentrate
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7.
Birkel, Emily Ann.
Application of a Portable Handheld Infrared Spectrometer for Quantitation of trans Fat in Edible Oils.
Degree: MS, Food Science and Technology, 2011, Ohio State University
► Trans fat has been linked to increased risk of heart disease, and…
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▼ Trans fat has been linked to increased risk of heart disease, and consumption poses a risk to consumers. FDA has mandated inclusion of trans fat on nutritional labeling, which has created a need for accurate, rapid analytical techniques. FTIR spectroscopy has been successfully applied to trans measurement, and advances in multivariate chemometric analysis and handheld FTIR spectrometers are promising for industrial applications. The objective of this study was to develop a methodology for the application of a portable handheld infrared spectrometer for the accurate measurement of trans fat in edible oils. Pure triglycerides were spiked with known levels of trans-trielaidin and spectra of heated samples were collected on a handheld FTIR spectrometer and benchtop FTIR as a reference method. Calibration models were created by measuring height of the second derivative band at 966 cm-1 and by partial least squares regression (PLSR). Predictive accuracy of the models was validated with an independent test set of commercial edible oils also spiked with trielaidin. Calibration models developed using PLSR and linear regression of band heights gave correlation coefficients R2 > 0.98. The handheld spectrometer coupled with the second derivative method did not produce accurate predictions. However, the handheld unit coupled with PLSR multivariate analysis gave standard error of prediction (SEP) of approximately 1%, comparable to values obtained with benchtop systems. This study demonstrates that handheld FTIR spectroscopy coupled with chemometrics is a suitable method for quantitation of trans fat. This combination is promising for in situ analysis of trans fat in edible oils.
Advisors/Committee Members: Rodriguez-Saona, Luis.
Subjects: Food Science
Keywords: trans fat; FTIR; chemometrics
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8.
Bowman, Tessa Leigh.
Analysis of factors affecting volatile compound formation in roasted pumpkin seeds with selected ion flow tube mass spectrometry (SIFT-MS).
Degree: MS, Food Science and Technology, 2011, Ohio State University
► Pumpkin (Cucurbita pepo and maxima) seeds are uniquely flavored and commonly consumed…
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▼ Pumpkin (Cucurbita pepo and maxima) seeds are uniquely flavored and commonly consumed as a healthy roasted snack. The objective was to determine dominant volatiles in raw and roasted pumpkin seeds, and the effect of seed coat, moisture content, fatty acid ratio, total lipids, reducing sugars and harvest year on volatile formation. Sensory was conducted to evaluate overall liking of seed variety and texture. Seed processing included: extraction from the fruit, dehydration and roasting (150 C). Oil extraction was done using soxhlet method, fatty acid profile using GC-FID and reducing sugars using 3,5 dinitrosalycylic acid reagent and uv spectroscopy. Headspace analysis of seeds was performed by a Selected Ion Flow Tube Mass Spectrometer (SIFT-MS). Volatiles dominating in raw pumpkin seeds were lipid aldehydes, ethyl acetate, 2, 3-butandione and dimethylsulfide. Compounds contributing to roasted aroma include alkylpyrazines, and Strecker and lipid aldehydes. Overall, hull-less seeds had higher volatile lipid aldehydes along with Strecker aldehydes. Seeds dehydrated to a moisture content of 6.5% before roasting had higher initial and final volatile concentrations than seeds starting at 50% moisture. Higher oil content resulted in higher lipid aldehyde formation during roasting and a moderate correlation between FFA ratio and corresponding lipid aldehyde was found. Harvest year (2009 vs. 2010) had a significant impact on volatile formation in hull-less seeds, but not as much as variety differences. No significant correlation was found between reducing sugars and volatile formation. Sensory showed that hull-less seeds were liked significantly more than hulled seeds.
Advisors/Committee Members: Barringer, Sheryl.
Subjects: Food Science
Keywords: Pumpkin Seeds, Volatile flavor, Roasted, (SIFT-MS), Fatty acids, Reducing sugars, Harvest, Variety
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9.
Bricker, Gregory Vincent.
Thermally Processing Broccoli Sprouts Impacts the Metabolism of Bioactive Isothiocyanates in Mice.
Degree: MS, Food Science and Technology, 2012, Ohio State University
► Broccoli sprouts are a rich source of glucosinolates, a unique group of…
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▼ Broccoli sprouts are a rich source of glucosinolates, a unique group of phytochemicals which may play a role in preventing multiple types of cancer. In order to exert physiologic activity, glucosinolates must be converted to their bioactive form, known as isothiocyanates, by the heat-labile enzyme myrosinase. This study had two objectives: First, to determine how heating broccoli sprouts affects glucosinolate content and subsequent isothiocyanate formation in vitro. Secondly, to understand how these results translate in vivo, by studying the metabolism of glucosinolates and isothiocyanates in mice fed diets containing thermally processed broccoli sprout powders (BSPs). Fresh broccoli sprouts received one of three processing treatments: (1) freeze-dried raw, (2) steamed and freeze-dried, or (3) heated at 60°C and freeze-dried. The sprouts were powdered, and then analyzed for differences in glucosinolate content and conversion to isothiocyanates. Three different mouse diets were prepared, each incorporating one of the BSPs at 4%, and fed for 7 days (n=10 mice/group). An additional group was fed a diet containing the purified isothiocyanate sulforaphane. 24 hours prior to sacrifice, all mice were exposed dorsally to ultraviolet light. Ultra performance liquid chromatography–mass spectrometry was utilized to quantify metabolites of the two predominant isothiocyanates, sulforaphane and erucin, in the plasma, liver, skin, lungs, kidneys, and bladder. Additionally, the activity of myeloperoxidase, a biomarker for inflammation, was measured in the skin. Steamed BSP had the greatest concentration of glucosinolates, followed by raw and 60°C treated BSPs. However, isothiocyanate formation from the raw and 60°C treated BSPs was approximately 5 and 23-fold greater, respectively, than the steamed BSPs, indicating that heating intensity has disparate effects on isothiocyanate formation. Mice fed the steamed BSP diet had the lowest concentrations of isothiocyanate metabolites in plasma and all tissue sites, while consumption of the 60°C-treated BSP diet generally resulted in the highest concentrations. Particularly high levels of isothiocyanate metabolites were detected in the bladder. Interestingly, we observed the isothiocyanates sulforaphane and erucin interconvert in vivo, with erucin being the vastly favored form at several tissue sites, even in mice fed the sulforaphane diet. Dietary administration of the BSPs did not reduce myeloperoxidase activity compared to the control group. In conclusion, in accordance with other studies, we show steaming severely hinders glucosinolate conversion to isothiocyanates upon consumption. Feeding broccoli sprouts treated at 60°C resulted in significantly greater concentrations of isothiocyanates at many organ sites. Lastly, once converted, chemopreventive isothiocyanates were distributed systemically to all tissue types analyzed.
Advisors/Committee Members: Schwartz, Steven.
Subjects: Food Science
Keywords: Glucosinolates; isothiocyanates; broccoli sprouts; cancer prevention; processing
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10.
Byrnes, Nadia.
Evaluating the Stability of Purple Corncob Extract in Tortilla Chips.
Degree: MS, Food Science and Technology, 2011, Ohio State University
► Color is the first attribute perceived by a consumer and often is…
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▼ Color is the first attribute perceived by a consumer and often is used as an indicator of a number of different product traits such as flavor, quality, and texture. Recently there has been an increase in consumer demand for the introduction of cleaner product labeling and the replacement of synthetic colorants with those derived from natural sources. Anthocyanins are a class of compounds that have received a significant amount of attention due to not only their associated health benefits but also their potential to serve as artificial color replacements. These pigments are sensitive to pH, oxygen, increased temperature, metals, sulfites, ascorbic acids, and a number of other compounds that serve as co-pigments. This study was conducted to assess the stability of an anthocyanin-rich purple corncob extract in a tortilla chip matrix during processing and over a six-month storage period. Purple corncob extract was produced by Sensus LLC (Hamilton, OH) by steam extracting the corncobs. At Wyandot Inc (Marion, OH) yellow corn was nixtamalized to prepare the masa to make tortillas. This extract was incorporated into masa at 1.84% just prior to tortilla chip production. The chips were bagged in foil bags and stored at ambient conditions. Chips were tested after production (time zero) and at one-month intervals for the duration of a six-month storage study. Samples were prepared by extracting the chips with a solution of 80% acidified methanol. The corncob and chip extracts were assayed for monomeric anthocyanin content, percent polymeric color, and total phenolic content. The anthocyanin and phenolic profiles of the extracts were also monitored. Additionally, the color coordinates of the chips were tested throughout the storage study to monitor any color change. In agreement with literature previously published, the anthocyanin profile of the corncob and tortilla chip extracts showed the presence of cyanidin-3-glucoside, pelargonidin-3-glucoside, and peonidin-3-glucoside (de Pascual-Teresa and others 2002, Jing and Giusti 2005, Yang and others 2009). The monomeric anthocyanin content of the corncob extract was 10.45 mg/g extract. In the tortilla chip extract, the monomeric anthocyanin content was found to be 0.038 mg/g tortilla chip. Percent polymeric color showed that in the chips the polymeric content increased up to three months, at which point polymers began to precipitate from solution. The total phenolic content of the corncob extract was 81.89 mg/g. Throughout the storage study, the monomeric anthocyanin content and total soluble phenolic content remained constant The color coordinates, measured with CIELab, showed a slight decrease, corresponding to a decrease in the vibrancy of the chips.
Advisors/Committee Members: Schwartz, Steven.
Subjects: Food Science
Keywords: anthocyanin; tortilla chip; purple corn
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11.
Chang, Hao Hsun.
Quantitative Changes of Volatile Compound in Soybean and Algal Oil and Effects of Antioxidants on the Oxidative Stability of Algal Oil under Light Storage.
Degree: PhD, Food Science and Technology, 2011, Ohio State University
► Lipid oxidation significantly affects the quality of foods. A simple and fast…
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▼ Lipid oxidation significantly affects the quality of foods. A simple and fast method for evaluating the oxidative stability of foods during storage is needed to determine its degree of oxidation. Soybean oil accounts for 75% of all vegetable oil consumed in the United States while algal oil is commercially available as a dietary supplement because of its health benefits. The oxidative stability of soybean and algal oil under light storage was evaluated by studying headspace oxygen depletion (HOD) and total volatile compound contents. Results suggest that the degree of oxidation increased as storage time increased in soybean and algal oil under light storage. The contents of 2-octenal, 4-nonenal and 3 unknown compounds in soybean oil and 1-octen-3-ol, 2,4-nonadiene, 2-heptenal, 2-octenal, 2,4-decadienal and 2-ethylfuran in algal oil increased up to a certain point and then decreased during light storage. Volatile compounds identified in algal oil under light storage were formed from the oxidation of oleic, linoleic and docosahexaenoic acid. Further oxidation of volatile compounds, including 2,4-decadienal and 2,4-heptadienal, and reactions between amine and carbonyl compounds may also lead to the formation of volatile compounds in algal oil under light storage, such as hexanal, 2-pentenal and benzothiazole. Results showed that there was no significant difference in the oxidative stability between soybean and algal oil during storage. However, differences in quantitative changes of volatile compound were observed. Differences in fatty acid composition in the two oils led to the differences in quantitative changes of volatile compound found under light storage. Algal oil was believed to have a lower oxidative stability than soybean oil under light storage becuase it contains large amounts of docosahexaenoic acid; however, the presence of photosensitizers in soybean oil and carotenoids in algal oil may explain why the oxidative stability of soybean oil was not greater than that of algal oil under light storage in this study. Algal oil is unstable and rapidly becomes rancid with undesirable “fishy” odors when it is stored for short lengths of time. The addition of antioxidants is a practical way to overcome odor problems during storage. The antioxidant and prooxidant activity of tocopherols, ascorbyl palmitate and rosemary extract in algal oil under light storage was investigated and their impact on the oxidative stability of algal oil under light storage was studied. Tocopherols acted as antioxidants at 1000 ppm or below but were prooxidants at 1500 and 2000 ppm in algal oil during light storage. Oxidized tocopherol compounds and radicals formed during tocopherol oxidation acted as prooxidants in algal oil. Ascorbyl palmitate and rosemary extract were found to improve the oxidative stability of algal oil at optimum concentrations under light storage. A ternary mixture of 1000 ppm tocopherols, 200 ppm ascorbyl palmitate and 1500 ppm rosemary extract exhibited maximum antioxidant activity in algal oil under light storage. However, ascorbyl palmitate above 200 ppm and rosemary extract above 1500 ppm were also prooxidants in algal oil under light storage. Caution should be taken with the use of high concentrations of tocopherols, ascorbyl palmitate and rosemary extract.
Advisors/Committee Members: Min, David B.
Subjects: Food Science
Keywords: volatile compound; oxidative stability; antioxidants; quantitative changes; algal oil
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12.
Chang, Wei-Lun.
Acetone-Butanol-Ethanol Fermentation by Engineered Clostridium beijerinckii and Clostridium tyrobutyricum.
Degree: PhD, Food Science and Technology, 2010, Ohio State University
► With the rising concerns of energy crisis, biofuel production becomes a very…
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▼ With the rising concerns of energy crisis, biofuel production becomes a very popular topic. As a possible replacement to transportation fuel, butanol attracted more attention because of its similar properties to automobile gasoline. Its low hygroscopicity and low vapor pressure may prevent increase in moisture content in butanol and make butanol a safe and environmentally friendly biofuel. Butanol can be produced by clostridia through acetone-butanol-ethanol (ABE) fermentation. However, this practice was not economically feasible with low titer, yield and productivity. The objectives of this study were to develop enhanced butanol production from ABE fermentation in continuous FBB by mutants of C. beijerinckii, and to explore the possibility of producing butanol by metabolic engineered hosts. A stoichiometric model was developed for the analysis of the metabolic pathway in ABE fermentation. The model helped process development by predicting the maximum butanol yield based on mass and energy balance at steady state in continuous process. In the stoichiometric analysis, the uptake of butyric acid was shown to benefit butanol production by reducing required energy to produce butanol. Two mutants of C. beijerinckii were cultured in continuous fermentation with butyric acid as a supplement in the medium under different conditions. At a high dilution rate of 1.88 h-1, asporogenic C. beijerinckii ATCC 55025 in the fibrous bed bioreactor (FBB) was able to utilize glucose and butyrate and steadily give a high butanol productivity of 17.29 g/(L*h), which was 170 folds higher than that in conventional batch fermentation. A new strain isolated from C. beijerinckii ATCC 55025 in repeated-batch culture in the FBB, C. beijerinckii JB200, was able to increase butanol titer to 12 g/L in continuous fermentation. In continuous fermentation, fibrous bed bioreactor (FBB) was used to help cell immobilization at high cell density. C. beijerinckii mutants were able to be retained at high cell density (>100 g dried weight/L) and steadily produce butanol without contamination or degeneration using both glucose and butyric acid. Besides solvent producing clostridia, metabolically engineered Clostridium tyrobutyricum could actively produce butanol over six repeated batches in the FBB using glucose and/or xylose. In batches with only xylose, more butanol was produced at 7.12 g/L with a higher yield with the slower cell growth that made the foreign enzyme competitive to the native enzyme for butyryl CoA. A pilot scale FBB was constructed for the evaluation of the feasibility of large scale butanol production in the FBB. Two batch fermentations were operated and the results of ABE fermentation were similar to those at lab scale. ABE fermentation at pilot scale was able to produce butanol at ~9.1 g/L with media containing glucose and butyric acid. In summary, continuous butanol production with improved productivity from ABE fermentation with supplement of butyric acid as additional carbon source in the FBB was demonstrated. More studies are necessary to improve butanol. At pilot scale, the FBB produced butanol with a result that was comparable to that at lab scale. The pilot scale FBB can be further operated under different modes for process optimization.
Advisors/Committee Members: Yang, Shang-Tian.
Subjects: Chemical engineering
Keywords: butanol; ABE fermentation; FBB
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13.
Costello, Seth Robert.
Effect of Electric Field on Growth Kinetics of Yogurt Starter Cultures, Lactobacillus bulgaricus and Streptococcus thermophilus.
Degree: MS, Food Science and Technology, 2012, Ohio State University
► Fully understanding how electric fields stimulate microbial growth could have huge implications…
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▼ Fully understanding how electric fields stimulate microbial growth could have huge implications in the food industry, especially the fermented food industry. More research is needed to determine how electric fields interact with microorganisms and what conditions cause a stimulating effect. The objective of this research was to evaluate the effects of various electric fields, including moderate electric field (MEF) and pulsed electric field (PEF), on the growth kinetics of various lactic acid bacteria in order to expand upon research that was previously limited to only Lactobacillus acidophilus. Common yogurt starter cultures, Lactobacillus bulgaricus and Streptococcus thermophilus, were subjected to MEF during fermentation in de Man Rogosa Sharpe (MRS) broth. The electric field strength remained constant throughout all experiments at 1 V/cm. Two vessels were created to allow for side by side fermentation comparison. One vessel was ohmically heated by passing a current through the MRS broth and the other vessel was heated conventionally using a heated water jacket. Fractions of the fermentation over time were collected for microbial enumeration as well pH measurement. Fermentation by S. thermophilus at 35°C with 45Hz MEF showed a reduced lag time of 2 hours 6 minutes as compared to the control which had a lag time of 2 hours 45 minutes. Increasing the temperature or frequency resulted in loss of the reduced lag time for S. thermophilus. L. bulgaricus showed no significant difference in growth or pH between the control and all treatments. The effect of pulsed electric field on the growth kinetics of various strains of lactic acid bacteria (LAB) was also investigated. Two fermentation vessels (for treatment and control) were filled with MRS broth and held at either 25°C or 35°C. The broth was inoculated with L. bulgaricus, S. thermophilus, or Lactococcus lactis (L. lactis) and was exposed to PEF at strengths ranging from 2-10 kV/cm during fermentation. Fractions of the fermentation collected over time were plated for microbial enumeration, tested for pH, and in the case of L. lactis, assayed for bacteriocin production. There was no growth stimulation effect observed for any culture at the conditions tested in these experiments. A general trend of reduced growth was seen as electric field was increased for both S. thermophilus and L. bulgaricus. It was hypothesized that L. lactis may produce the bacteriocin nisin at an increased rate due to cell stress and self induction from pore formation caused by the PEF treatments, but the opposite was found. The control produced nisin slightly faster showing the first clearing zone (200 arbritrary units) at 10 hours with the treated showing the first clearing zone (200 arbritrary units) at 11 hours. Although a stimulation effect was not observed in these experiments, further research utilizing differing treatment parameters would be needed in order to claim that mild PEF does not cause the stimulation of bacterial growth.
Advisors/Committee Members: Yousef, Ahmed.
Subjects: Food Science
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14.
DiCaprio, Erin L.
Attachment, Internalization, and Dissemination of Human Norovirus and Animal Caliciviruses in Fresh Produce.
Degree: MS, Food Science and Technology, 2012, Ohio State University
► Fresh produce is a high risk food for human norovirus (NoV) contamination,…
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▼ Fresh produce is a high risk food for human norovirus (NoV) contamination, because it can easily become contaminated at both the pre- and post-harvest stages of cultivation. Disease surveillance has shown that human NoV is attributed to 40% of all fresh produce related outbreaks reported each year in the U.S. However, the ecology, persistence, and interaction of human NoV and fresh produce are all poorly understood. Increasing outbreaks of viruses in fresh and fresh-cut vegetables and fruits give high urgency to understanding the interaction of human NoV with fresh produce in order to develop effective preventive measures. In this research, the attachment, uptake, internalization, and dissemination of human NoV and its surrogates (murine norovirus, MNV-1; and Tulane virus, TV) were evaluated. First, the attachment of human NoV surrogates to fresh produce was visualized using confocal microscopy. Purified human NoV virus-like particles (VLPs), TV, and MNV-1 were conjugated with biotin, and subsequently applied to either Romaine lettuce or green onion. The biotinylated virus particles were visualized by incubation with streptavidin coated Quantum Dots (Q-Dots 655), which emit fluorescence that can be viewed using a confocal microscope. It was found that all three surrogates attached to the surface of Romaine lettuce leaves and were found aggregating in and around the stomata. Similarly, human NoV VLPs, TV, and MNV-1 were found to attach to the surface of Romaine lettuce roots. In the case of green onions, human NoV VLPs were found between the cells of the epidermis of both the shoots and roots. However, TV and MNV-1 were found to be covering the surface of the epidermal cells in both the shoots and roots of green onions. The results indicate that different viruses vary in their attachment patterns to different varieties of fresh produce. A quantitative assessment of the level of attachment of a human NoV GII.4 strain, TV, and MNV-1 was executed using Romaine lettuce as a model system. Romaine lettuce roots and shoots were inoculated with varying levels of TV and MNV-1 and then washed with PBS to remove unattached viruses. It was found that simple washing removed less than 1 log of viruses from the shoots and 1-4 log of viruses from the roots, demonstrating that TV and MNV-1 bound more efficiently to Romaine lettuce leaves than to the roots. A human NoV GII.4 strain was inoculated at a level of 7 log RNA copies/g to Romaine lettuce leaves and roots, and then washed with either PBS or 200ppm of chlorine. The human NoV GII.4 strain was found to attach similarly the both the Romaine lettuce leaves and roots, and that washing with 200ppm of chlorine removed less than 1 log of viral RNA copies from the tissues. The results demonstrate that different viruses attach differently to Romaine lettuce, and that washing is ineffective in removing viral contamination from fresh produce. Next, it was determined whether human NoV and its surrogates could be internalized via roots and disseminated to edible portions of the plant. The roots of Romaine lettuce growing in hydroponic feed water were inoculated with 6 log RNA copies/ml of human NoV GII.4 strain or 6 log PFU/mL of human NoV surrogates(TV and MNV-1), and plants were allowed to grow for 2 weeks. Leaves, shoots, and roots were harvested at days 0, 1, 3, 7, and 14 after virus inoculation. The plant tissues were homogenized and viral titers and/or RNA were determined by plaque assay and/or real-time RT-PCR. For human NoV, high levels of viral genome RNA (5-6 log RNA copies/g) were detected in leaves, shoots, and roots at day 1 post-inoculation and remained stable over the 14 day study period. For MNV-1 and TV, relatively low levels of infectious virus particles (1-3 log PFU/ml) were detected in leaves and shoots at days 1 and 2 post-inoculation, but reached a peak titer (5-6 log PFU/g) at days 3 or 7 post-inoculation. In addition, human NoV had a rate of internalization comparable with TV as determined by real-time RT-PCR, whereas, TV was more efficiently internalized than MNV-1 as determined by plaque assay. To further confirm the viral internalization via lettuce roots, an identical experiment was performed with the exception that the harvested plant tissues were submerged in 50 ml of 1000 ppm chlorine for 5 min to eliminate any possible viral contaminations. The results showed that there were no significant differences observed in viral internalization in chlorine treated shoots and leaves on any of the study days compared to the untreated samples (P>0.05) during the experimental period. Taken together, these results demonstrated that human NoV and animal caliciviruses attached tightly to roots, became internalized via roots, and efficiently disseminated to the shoots and leaves of the lettuce. In summary, this research elucidates a major gap in our understanding of the ecology of human NoV in fresh produce, specifically, our understanding of the fate of human NoV after attaching to roots of growing lettuce. Elucidation of the mechanism of virus-plant interaction will facilitate the development of novel interventions to prevent viral attachment and internalization in plants.
Advisors/Committee Members: Li, Jianrong.
Subjects: Food Science; Virology
Keywords: human norovirus; Tulane virus; murine norovirus; fresh produce; romaine lettuce; internalization; dissemination
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15.
Feliciano, Lizanel.
The efficacy of ware-washing protocols for removal of foodborne viruses from utensils in restaurants and food service establishments.
Degree: PhD, Food Science and Technology, 2012, Ohio State University
► Food contact surfaces may present a potential health hazard if they are…
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▼ Food contact surfaces may present a potential health hazard if they are not properly cleaned and sanitized. Contaminated surfaces (e.g. utensils, cutting boards, equipment) have been identified as sources of cross-contamination for food during preparation and when being served to consumers. Therefore, ensuring effective cleaning and sanitization of food contact surfaces may help in the spread of foodborne pathogens and incidence of outbreaks. The FDA Food Code and NSF International standards mandate that all surfaces/tableware items should be free of food soils and that a minimum microbial reduction of 5 logs must be obtained before surface sanitization could be considered effective. To comply with these standards, food service establishments must clean and sanitize food contact surfaces either manually or mechanically. Unfortunately, the standards set for these ware-washing methods specifically address the reduction of bacterial numbers from food contact surfaces, and not viruses. Therefore, information regarding the effectiveness of these standards against viruses needs to be elucidated. The first part of this dissertation (Chapter 2) compared the efficacy of sodium hypochlorite (chlorine) and quaternary ammonium compound (QAC) in reducing bacterial populations (Escherichia coli K-12 and Listeria innocua) and murine norovirus (MNV-1) counts on different food contact surfaces (ceramic plates, stainless steel forks and drinking glasses). Each microorganism was separately inoculated into 2% reduced fat UHT milk and creamcheese spread. The milk was used to contaminate the drinking glasses and the spreadable cream cheese was used on the ceramic plates and forks. All tableware items were manually and mechanically washed and sanitized. Bacterial and viral counts were then determined on the surface of each tableware item using the plaque assay and plate count methods, respectively. This study found that QAC and sodium hypochlorite sanitizers had the ability to produce greater than/equal to 5 log reductions on both E. coli and L. innocua in manual and mechanical ware-washing operations. However, they were unable to produce the same level of antiviral activity (less than/equal to 3 logs) under similar conditions irrespective of the nature of the tableware item and the ware-washing protocol. The second part of this dissertation (Chapter 3) evaluated the efficacy of the manual and mechanical ware-washing protocols to remove caliciviruses from food contact surfaces (ceramic plates, stainless steel forks and drinking glasses). Porcine sapovirus (PoSaV) was used as a surrogate for both noroviruses (NoVs) and sapoviruses (SaVs). The tableware items were contaminated with the milk (drinking glasses) and cream cheese spread (ceramic plates and forks) inoculated with PoSaV. These were manually and mechanically washed and sanitized with different sanitizing solutions (chlorine and QAC). Tap water was used as the control sanitizing solution. After the ware-washing operations, the viral counts on the surfaces were determined by 50% tissue culture infective dose (TCID50). The chlorine sanitizer was able to reduce PoSaV by approximately 2 logs when exposed to higher temperatures during mechanical ware-washing (49ºC vs. 43ºC during manual ware-washing). The viral reductions achieved with the other sanitizers (QAC and control) were not significant (less than 1 log). The third part of this dissertation (Chapter 4) investigated the effect of different sanitizers [chlorine-based sanitizers (bleach and Chlor-Clean), QAC and tap water] on their abilities to remove milk samples from underlying ceramic and glass surfaces. Three types of milk samples were tested in this study: 1) plain milk; 2) milk inoculated with MNV-1; and 3) milk inoculated with PoSaV. Atomic force microscopy (AFM) was used to determine the thicknesses of the milk films left after the surfaces were mechanically washed and sanitized. Results from this study suggested that milk samples contaminated with viruses tend to adhere to a greater extent (thicker films) than non-contaminated milk and that common sanitizing solutions (chlorine-based and QAC sanitizers) appeared not to effectively remove milk-virus deposits from simulated food contact surfaces.
Advisors/Committee Members: Pascall, Melvin.
Subjects: Food Science; Public Health
Keywords: ware-washing protocols, foodborne viruses, sanitizers, food safety, caliciviruses, restaurants
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16.
Fisher, Erica L.
Physicochemical Characterization of a Novel Strawberry Confection for Delivery of Fruit Bioactives to Human Oral Mucosa.
Degree: MS, Food Science and Technology, 2011, Ohio State University
► Oral diseases are a common health concern in the United States, and…
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▼ Oral diseases are a common health concern in the United States, and studies have revealed that poor oral health may lead to increased risk of certain chronic diseases. Strawberry phytochemicals, such as ellagitannins, anthocyanins, flavonols, and catechins, are known to elicit health benefits by anti-inflammatory and anti-oxidant properties that can improve oral health. A unique starch-based confection containing freeze-dried strawberries was developed to provide sustained, targeted release of phytochemicals to the oral mucosa to promote oral health in a human clinical trial. The objective of this study was to compare physicochemical properties of the confection with in vitro dissolution studies to evaluate the facility of the confection to sustain phytochemical release in the oral cavity in a phase I/II clinical trial. Water distribution was assessed with thermogravimetric analysis. Texture profile analysis and small oscillatory amplitude testing were used to characterize the behavior of the gel structure under deformation as it related to oral processing. In vitro dissolution kinetics in artificial saliva was evaluated for release of total phenolics and total monomeric anthocyanins. Stability of the freeze-dried strawberry confectionery was assessed during a fourteen-day storage period. The moisture content was determined to be approximately 20% and decreased during storage, which should be taken into account when manufacturing the confections for a clinical trial as changes in moisture content and water dynamics will impact the shelf stability. It was also determined that hardness, gumminess, and chewiness varied significantly with storage. Rheological characterization of the confectionery showed that the behavior of the microstructure of the food matrix under deformation was frequency- and shear-dependent. Throughout oscillatory frequency testing, the confectionery exhibited a higher elastic modulus than viscous modulus, indicating a more solid-like behavior upon deformation. Similarly, the viscosity of the confection decreased in a Newtonian-like manner until reaching the time constant shear value, at which pseudoplastic behavior was observed in the range of frequencies typically observed during oral manipulation of semisolid foods. Temperature changes between room temperature and body temperature showed minimal effects on the elastic and viscous moduli. In vitro dissolution testing revealed that after six hours of testing, 83% total phenolics and 86% monomeric anthocyanins were released. A phase I/II pilot clinical trial was conducted to evaluate the efficacy of strawberry bioactives delivered by the novel confectionery to prevent oral disease in smoking and non-smoking men and women. Participant compliance to diet, smoking, and confectionery consumption was evaluated. It was found that the optimized confectionery formulations were well-tolerated and subject compliance was good. The strawberry confectionery showed great potential as a novel vehicle by which fruit bioactives may be delivered to oral tissue. Further analysis of biological samples is needed to determine the tissue deposition and subsequent gene modulation of the novel functional confectionery.
Advisors/Committee Members: Vodovotz, Yael.
Subjects: Food Science
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17.
Ge, Chongtao.
Salmonella Typhimurium Internalization in Fresh Produe under Plant Stress, and Inactivation of Internalized Salmonella Using Ultraviolet-C Irradiation and Chemical Disinfectants.
Degree: PhD, Food Science and Technology, 2012, Ohio State University
► Internalization of human pathogens is common in fresh produce.This threatens human health…
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▼ Internalization of human pathogens is common in fresh produce.This threatens human health because the pathogens cannot be fully inactivated by conventional washing. This study examined the impact of water stress (abiotic factor) on the internalization of Salmonella Typhimurium in iceberg lettuce and green onion through soil and plant surface contamination during the pre-harvest stage. In addition, lettuce mosaic virus (LMV) infection (biotic factor) was introduced to determine whether the internalization via surface inoculation was affected in lettuce. Finally, different doses of ultraviolet-C radiation and their combination with chlorine/peracetic acid (PAA) were applied in an attempted to inactivate the internalized Salmonella. Salmonella was labeled with green fluorescence protein (GFP) and different concentrations of GFP-labeled Salmonella were inoculated into the rhizosphere-soil or sprayed on the leaf surface of the 4-week-old plants. LMV infection was only conducted in the surface-contaminated lettuce. The plants were irrigated with different volumes of water (drought, storm), collected after 2 days and cut into two parts (leaf, root/bottom) after surface disinfection to remove the attaching bacteria. Plate count and qPCR were used to determine the viable and total internalized Salmonella. The internalized Salmonella (via surface contamination) was also visualized using a laser scanning confocal microscope. This study discovered S. Typhimurium can disseminate throuought the entire plant after penetrating into the tissues through the roots or leaves. The viable Salmonella was detected in both parts of green onion, however, was only found in the lettuce leaves regardless of contamination method. However, once the lettuce was infected with LMV, the viable Salmonella showed up in the both parts. The water stress alone did not influence the internalization level in the lettuce when contaminated on the surface, or in the green onion using either contamination method. The viable Salmonella was only detectable in the lettuce when the soil was contaminated with 108 or 109 CFU/g-soil of bacteria. Additionally, the viable internalized Salmonella levels were generally higher under these conditions than if the lettuce were watered optimally. On the other hand, the extent of viable internalized Salmonella decreased in the leafy part of the LMV-infected lettuce under the water stress conditions when the lettuce was contaminated with 104 and 106 CFU/ml of Salmonella on the surface. For the disinfection study, Salmonella (108 CFU/ml) was spread on the lettuce surface and injected into the bottom part of green onion to generate bacterial internalization. The plants was collected after 2 days and subjected to surface cleaning before treatments. Significant reduction was achieved in the lettuce treated with high UV-C doses (150 450, 900 mJ/cm2) or UV-C-chlorine or -PAA, and in the green onion treated with with UV-C-chlorine or –PAA or UV-C doses of 150, 900 mJ/cm2. The plant firmness was well-maintained, although the lettuce changed color slightly when treated with 900 mJ/cm2 of UV-C. This is the first study assessing the risks of pathogen internalization in fresh produce under the impact of abiotic and biotic environmental factors. It also provides applicable research outcomes for developing practical methods to inactivate internalized pathogens for industry settings.
Advisors/Committee Members: Yousef, Ahmed.
Subjects: Food Science
Keywords: Salmonella; internalization; fresh produce; extreme weather; phytovirus infection
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19.
Grasso, Elizabeth Marie.
Nonthermal intervention strategies to minimize pathogenic foodborne microorganisms.
Degree: PhD, Food Science and Technology, 2010, Ohio State University
► It is estimated that there are over 76 million cases of foodborne…
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▼ It is estimated that there are over 76 million cases of foodborne illnesses caused by consumption of foods contaminated with pathogenic foodborne microorganisms in the United States each year. To minimize the incidence of pathogenic microorganisms in minimally processed foods while maintaining quality characteristics, nonthermal processing technologies are needed. High pressure processing, electron-beam irradiation and antimicrobial surface coatings are three intervention strategies that can reduce microbial foodborne pathogens when there is insufficient heat to destroy them. These technologies have the advantage of low heat or minimal thermal processing conditions, ideal for fresh food products. This research investigates the efficacy of these nonthermal techniques on nonpathogenic surrogates of pathogenic foodborne microorganisms. Chapter number 2 discloses the result of an investigation of the inactivation potential of high pressure processing on Salmonella Typhimurium inoculated commercial peanut butter samples and peanut based food matrices. Chapter 3 describes the electron-beam irradiation dosage required to pasteurize, via complete inactivation of a target non-sporeforming microorganism, fresh-cut cabbage samples inoculated with Escherichia coli K12. Chapter 4 is a study of the efficacy before and after an accelerated longevity testing of several commercially available antimicrobial surface coatings against a cocktail of Listeria innocua, Escherichia coli K12, and Salmonella Typhimurium. The findings in Chapter 2 indicate minimal reductions Salmonella Typhimurium inoculated into commercial and model peanut butter samples. Chapter 3 shows electron-beam irradiation was highly effective at reducing the indigenous and inoculated microflora present in the fresh-cut cabbage samples as seen using general plate count agar and selective differential agar to determine survival of microorganisms in both uninoculated and inoculated cabbage samples at 0, 1.0, 2.3, and 4.0 kGy electron-beam irradiation. Chapter 4 discloses minimal effectiveness of commercial antimicrobial surface coatings at inactivation of a cocktail of three surrogate microorganisms inoculated onto the surfaces. These results help advance our understanding of nonthermal technologies and help increase the safety of the food supply through application of three nonthermal food processing treatments.
Advisors/Committee Members: Lee, Ken.
Subjects: Food science
Keywords: Nonthermal processing; high pressure processing; electron-beam irradiation; antimicrobial surface coatings
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20.
GUPTA, ROCKENDRA.
Pressure Assisted Thermal Processing: Tomato Carotenoid Stability during Processing and Storage and Feasibility of Using Chemical Markers for Evaluating Process Uniformity.
Degree: PhD, Food Science and Technology, 2011, Ohio State University
► Lycopene is a major carotenoid in tomatoes and epidemiological studies suggest that…
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▼ Lycopene is a major carotenoid in tomatoes and epidemiological studies suggest that consumption of food rich in carotenoids lowers the risk of developing certain types of cancer and chronic diseases. However, very little is known about its fate in tomato products subjected to a range of combined pressure-temperature (P-T) treatments. Likewise, little is known about the pressure-temperature uniformity during combined P-T processing. This study was conducted to investigate the effect of pressure-thermal treatments (0.1, 500, 600 & 700 MPa; 30-100 deg. C, different time intervals) on post processing extractability, isomerization, bioaccessibility and storage stability of lycopene in tomato juice. Finally, a study was conducted to evaluate the feasibility of using a chemical M-2 (4-Hydroxy-5-methyl-3(2H)-furanone) as a potential marker for understanding combined P-T process non-uniformity. Combined pressure-thermal treatments (Pressure Assisted Thermal Processing (PATP), High Pressure Processing (HPP)) resulted in up to 12% increase in lycopene extractability over thermally processed (TP) and unprocessed control tomato juice. In addition, all-trans lycopene showed stability to isomerization in tomato juice samples subjected to HPP, PATP and TP. The post processing retention of β-carotene was a function of processing time, temperature, pressure, cultivar used and type of juice (raw vs. hot break). During storage, lycopene degradation varied as a function of cultivar, processing method, storage temperature, and time. Increase in storage temperatures also increased degradation. Among the stored juices, HPP processed juice showed the least lycopene degradation. Also, HPP and PATP juice samples better retained lycopene cis isomers and color during storage. β-carotene showed good stability in the processed samples during storage. A two-step first order equation was used to predict the changes in lycopene concentration over the course of storage. The processed juice samples also showed microbial stability over the course of 52 week storage at 4, 25 and 37 deg. C. The in-vitro bioaccessibility studies showed that regardless of the processing conditions, less than 0.5% of the lycopene originally present in the processed juice got micellarized. No significant difference was found between the amount micellarized between various treatments (p>0.05). All-trans β-carotene micellarization in the processed juice (HPP, PATP, TP) was significantly higher (p<0.05) as compared to the raw unprocessed juice (control). Interestingly, hot break juice subjected to P-T treatments showed 15-30% more all-trans β-carotene micellarization than the raw juice subjected to similar P-T treatments. The formation and stability of chemical marker M-2 was influenced by heat (which favored the marker formation), pressure (which hindered marker formation) and pH (higher pH hindered marker formation). The initial concentrations of M-2 in the gels were 9.17 and 6.10 mg/100g at pH 6.10 and 8.25, respectively. The marker yield during thermal treatment (at 0.1 MPa, 105 deg. C) increased with increase in holding time (following a first order kinetics) and decreased with increasing pH. Pressure treatments from 350 to 700 MPa at 30 deg. C reduced the chemical marker formation for both pH values investigated. The net final concentration of the marker formed during PATP was higher than HPP, but lower than thermal treatments. In summary, the present research shows that combined pressure-temperature treatments could be an attractive approach for preserving tomato juice quality.
Advisors/Committee Members: Balasubramaniam, V.M.
Subjects: Agricultural Engineering; Biochemistry; Chemical Engineering; Chemistry; Food Science
Keywords: Tomato, carotenoids, lycopene, beta carotene, high pressure processing, pressure assisted thermal processing, combined pressure-temperature processing, bioaccessibility, carotenoid stability, isomerization, pressure temperature non-uniformity
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21.
Hart, Ashley Yeong.
Effects of resistant starch and soluble fiber on the bioaccessibility of dietary carotenoids from spinach and carrot using simulated in vitro digestion.
Degree: MS, Food Science and Technology, 2012, Ohio State University
► We evaluated the effects of soluble fiber, including oligosaccharides, and resistant starch…
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▼ We evaluated the effects of soluble fiber, including oligosaccharides, and resistant starch on the micellarization of lutein, α-carotene, and β-carotene from a raw spinach and carrot “salad” using a simulated in vitro digestion. Fiber variables were either combined with raw salad alone or with raw salad and nonfat yogurt to simulate a more complex meal. Raw and ripe bananas were used to examine the potential impact of the natural, inherent resistant starch fiber in the banana on the micellarization of lutein, α-carotene (AC), and β-carotene (βC). It was expected that the soluble fibers, fructooligosaccharide (FOS), galactooligosaccharide (GOS), and pectin, as well as fibers displaying characteristics of soluble fiber, such as resistant starch (RS) would decrease xanthophyll and carotene micellarization as previous soluble fiber studies had shown in vitro and in vivo. The efficiency with which lutein, 13-cis-β-carotene, α-carotene, β-carotene, and 9-cis-β-carotene from the raw salad partitioned in the aqueous fraction were 54.1 ± 1.3%, 18.5 ± 0.6%, 22.0 ± 1.4%, 19.6 ± 1.0%, and 52.7 ± 2.2%, respectively. High viscosity citrus pectin significantly inhibited micellarization of lutein (α< 0.0001), 13-cis-β-carotene (α< 0.0001), α-carotene (α< 0.0001), β-carotene (α< 0.0001), and 9-cis-β-carotene (α< 0.0001) relative to the fiber free control at 4% (wt: wt). Unexpectedly, oligosaccharide and resistant starch samples (FOS, GOS, RS2, and RS3) significantly increased micellarization of lutein, AC, and βC. Micellarization of lutein in the spinach and carrot salad was significantly increased by 12%, 12%, and 14% with the addition of 2% FOS (α= 0.0377), 4% FOS (0.0306), and 2% RS3 (α= 0.0054), respectively. Alpha- and beta-carotene showed very similar results. Micellarization of beta-carotene was significantly increased by 41%, 60% and 49% with the addition of 2% (wt: wt) FOS (α= 0.0136), RS2 (α< 0.0001), and RS3 (α= 0.0014), respectively. Micellarization of beta-carotene cis isomers was significantly increased with the addition of both 2% and 4% (wt: wt) FOS, GOS, RS2 and RS3. The combination of yogurt and salad did not significantly affect micellarization of lutein, AC or βC. There was no significant difference in extent of micellarization of carotenoids between raw and ripe banana. The results from this study indicate that the presence of 2-4% FOS, GOS, and RS ingredients will not compromise the bioaccessibility of carotenoids in a meal.
Advisors/Committee Members: Schwartz, Steven.
Subjects: Agriculture; Analytical Chemistry; Anatomy and Physiology; Biology; Chemistry; Food Science; Health
Keywords: carotenoids; in vitro digestion; micellarization; soluble fiber; oligosaccharides; fructooligosaccharide; galactooligosaccharide; resistant starch; carotenoid bioaccessibility; nutrition; digestion; food science; HPLC
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22.
Hostetler, Gregory.
Effects of enzymatic and thermal processing on flavones, the effects of flavones on inflammatory mediators in vitro, and the absorption of flavones in vivo.
Degree: PhD, Food Science and Technology, 2011, Ohio State University
► Flavones are abundant in parsley and celery and possess unique anti-inflammatory properties…
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▼ Flavones are abundant in parsley and celery and possess unique anti-inflammatory properties in vitro and in animal models. However, their bioavailability and bioactivity depend in part on the conjugation of sugars and other functional groups to the flavone core. Two studies were conducted to determine the effects of processing on stability and profiles of flavones in celery and parsley, and a third explored the effects of deglycosylation on the anti-inflammatory activity of flavones in vitro and their absorption in vivo. In the first processing study, celery leaves were combined with beta-glucosidase-rich food ingredients (almond, flax seed, or chickpea flour) to determine test for enzymatic hydrolysis of flavone apiosylglucosides. Although all of the enzyme-rich ingredients could convert apigenin glucoside to aglycone, none had an effect on apigenin apiosylglucoside. Thermal stability of flavones from celery was also tested by isolating them and heating at 100 °C for up to 5 hours in pH 3, 5, or 7 buffer. Apigenin glucoside was most stable of the flavones tested, with minimal degradation regardless of pH or heating time. Apigenin, luteolin, and chrysoeriol were stable at pH 3, but degraded steadily at pH 5 or 7. Apigenin apiosylglucoside was least stable at pH 3, but its primary degradation product was apigenin glucoside. Further experiments with thermal processing and enzyme treatments showed that apigenin apiosylglucoside could be converted stepwise to apigenin glucoside and then to aglycone, resulting in over 95% conversion of total apigenin derivatives. The second processing study explored the effects of juice extraction, acidification, thermal processing, and endogenous enzymes on flavone profiles and concentrations in parsley and celery. Parsley yielded 72% juice with 64% of the total flavones extracted, while celery yielded 79% juice with 56% of flavones extracted. Fresh parsley juice averaged 281 mg flavones/100 g, and fresh celery juice 28.5 mg/100 g. Flavones in steamed parsley and celery were predominantly malonyl apiosylglucoside conjugates, while those in fresh samples were primarily apiosylglucoside conjugates; this was apparently the result of endogenous malonyl esterases. Acidification and thermal processing of celery converted flavone apiosylglucosides to flavone glucosides, resulting in a juice that could improve the bioavailability and efficacy of these potentially beneficial compounds. In the third study the anti-inflammatory activities of celery extracts, some rich in flavone aglycones and others rich in flavone glycosides, were tested on the inflammatory mediators TNF-alpha and NF-kappaB in LPS-stimulated macrophages. Pure flavone aglycones and aglycone-rich extracts effectively reduced TNF-alpha production and inhibited transcriptional activity of NF-kappaB, while glycoside-rich extracts showed no significant effects. Deglycosylation of flavones increased cellular uptake and cytoplasmic localization as shown by HPLC and by staining with DPBA. Celery diets with different glycoside or aglycone contents were formulated, and absorption was evaluated in mice fed with 5% or 10% celery diets. Relative absorption was significantly higher in mice fed aglycone-rich diets as determined by HPLC-MS/MS. The results demonstrated that deglycosylation increases absorption of dietary flavones in vivo and modulates inflammation by attenuating TNF-alpha and NF-kappaB, suggesting the potential use of flavone-rich functional foods for the treatment or prevention of inflammatory diseases.
Advisors/Committee Members: Schwartz, Steven.
Subjects: Analytical Chemistry; Biochemistry; Cellular Biology; Food Science; Nutrition
Keywords: flavones, inflammation, food processing, enzymes, thermal stability, absorption
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23.
Huang, Yang.
Adhesion of Food Powders During Coating and the Effects of Alkalization and Roasting Conditions on Cocoa Volatile Compounds.
Degree: PhD, Food Science and Technology, 2010, Ohio State University
► The effects of powder resistivity, coating voltage, relative humidity and coating density…
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▼ The effects of powder resistivity, coating voltage, relative humidity and coating density on adhesion were investigated in both nonelectrostatic and electrostatic coating. Cocoa powder with a high resistivity (1.15E+13 Ωm) showed a stronger electrostatic adhesion than starch powder with a medium resistivity (2.56E+10 Ωm) and NaCl powder with a low resistivity (7.31E+5 Ωm). The adhesion of starch and cocoa powders coated at 0, 40 and 95 kV increased with increasing voltage. The adhesion at 0 kV was in the range of the theoretically calculated van der Waals force, and the measured adhesion forces at 40 kV and 95 kV were in the range of the theoretically calculated electrostatic image force at 40 kV and 95 kV respectively. For nonelectrostatic coating (0 kV), there was no significant change in adhesion when relative humidity (RH) increased from 30% to 60%, while adhesion increased when RH increased from 60% to 80%. For electrostatic coating, the adhesion decreased when RH increased from 30% to 60%, but the adhesion at 80% RH, close to the theoretically calculated capillary force value, was larger than the adhesion at 30% and 60% RH. For both nonelectrostatic and electrostatic coating, the adhesion force decreased as coating density increased to 1.0 mg/cm2, but there was no significant change from 1.0 mg/cm2 to 2.0 mg/cm2. Cocoa beans were alkalized before or after roasting and made into cocoa liquor before analyzing by selected ion flow tube-mass spectrometry (SIFT-MS). In both alkalized-before-roasting and alkalized-after-roasting samples, there were significantly higher concentrations of alkylpyrazines for the samples with pH above 7.0 than pH below 7.0. At pH 8, the concentrations of 2,3-, 2,5- and 2,6-dimethylpyrazine (DMP), 2,3,5-trimethylpyrazine (TrMP), 2,3,5,6-tetramethylpyrazine (TMP) and 2,3-diethyl-5-methylpyrazine (EMP) in the samples alkalized-before-roasting were higher than those in the samples alkalized-after-roasting. Volatiles increased under conditions that promoted the Maillard reaction. The partition coefficient was not significantly affected by pH from 5.2 to 8.0. The ratios of TrMP/DMP and DMP/TMP increased while the ratio of TMP/TrMP decreased as the pH increased. The concentrations of Strecker aldehydes and other volatiles followed a similar pattern as that of the alkylpyrazines. High pH favors the production of alkylpyrazines and Strecker aldehydes. Alkalized and unalkalized Don Homero cocoa beans were roasted at 120, 150 and 170 °C in a rotary roaster. The real-time and end-of -roasting concentrations of cocoa volatiles in the headspace of the roaster were analyzed by SIFT-MS. The concentrations of total alcohol, acids, aldehydes, esters, ketones and alkylpyrazines reached peak concentrations within the first 15 min roasting. The concentrations of alkylpyrazines and Strecker aldehydes increased as the roasting temperature increased from 120 to 170 °C. For most of the volatile compounds compared, there was no significant difference between Arriba and Don Homero beans, but Arriba beans showed higher concentrations of 2-heptanone, acetone, ethyl acetate, methylbutanal, phenylacetaldehyde and trimethylpyrazine than Don Homero beans. For unalkalized Don Homero beans (pH 5.7), the time to peak concentration decreased from 13.5 to 7.4 min for pyrazines, and from 12.7 to 7.4 min for aldehydes as the roasting temperature increased from 120 to 170 °C. Also, at 150 °C roasting, the time to peak concentration was shortened from 9.0 to 5.1 min for pyrazines, and from 9.1 to 5.0 min for aldehydes as the pH increased from 5.7 to 8.7.
Advisors/Committee Members: Barringer, Sheryl A.
Subjects: Food science
Keywords: adhesion, electrostatic coating, food powder, cocoa, alkylpyrazine, volatile, Maillard reaction, alkalization, roasting
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24.
Hu, Feifei.
Application of High Performance Liquid Chromatography (HPLC) and Fourier Transform Infrared (FTIR) Spectroscopy to Swiss-type Cheese Split Defects.
Degree: MS, Food Science and Technology, 2012, Ohio State University
► Splits, slits and cracks are a continuing problem in the US Swiss…
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▼ Splits, slits and cracks are a continuing problem in the US Swiss Cheese industry and cause downgrading of the cheese, bringing economic loss. The defects generally occur during secondary fermentation in cold storage, which is known to be an issue caused by many factors. Many chemical and physical changes can be indicators to help predicting the defects. Various techniques have been applied to test different compounds in cheese. HPLC is one of the reference methods which have been applied in cheese chemistry for the past decades. Its application involves in the qualification and quantification of organic acids, amino acids and peptides, and sugars in dairy products. However, limited research has been conducted on a rapid and easy testing regimen to investigate split defects in Swiss-type cheese. For over fifty years, researchers have investigated the application of Fourier Transform Infrared (FTIR) Spectroscopy in various food samples, including cheeses and other dairy products because FTIR spectroscopy gives fast, simple and comprehensive detection of chemical compounds. There is great potential for applying FTIR spectroscopy in developing a rapid test method to detect and predict the occurrence of split defects. In this study, initially four pairs of cheese samples were analyzed using a standard HPLC methodology, to assess the capability of this method in chemical detection addressing the defects, and to provide a reference to later FTIR results. Four pairs of cheeses, each pair from its own vat, were chosen for this analysis. Each pair of cheeses contained one defective item and one non-defective item. Three major organic acids (oxalic, pyruvic and lactic acid) in the Swiss cheese extract were detected. Oxalic Acid concentration remained constant over the samples and the concentrations of the two remaining acids were determined by standard curves. The HPLC results showed a lower level of lactic acid concentration and also a higher ratio of pyruvic acid to lactic acid in cheeses with split defects than cheeses with good grades. At the same time, Fourier Transform Infrared (FTIR) supported HPLC results. The spectra information showed significant difference between the pair members in the wavenumbers range corresponding to these organic acids. Modification of the sampling method was applied, with the FTIR analysis being used on a further nine individual cheese samples. The sampling was done from different areas of split, “eye” and “blind” from each cheese. This allowed FTIR spectra to give more significant differentiation between defective and non-defective samples. Better differentiation was attained following modification of the sampling method, with a shift of significant wavenumber ranges, from organic acid bands to amino acid bands. Results showed the application of FTIR in Swiss-type Cheese has great potential, targeting different compounds to address split defects.
Advisors/Committee Members: Harper, W. James.
Subjects: Food Science
Keywords: Swiss-type cheese; split defects; HPLC; FTIR
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25.
Ie, Pauline S.
Gelatinization and Molecular Properties of Organic and Conventional Rice and Spelt Starches.
Degree: MS, Food Science and Technology, 2011, Ohio State University
► Gelatinization properties of organic and conventional rice and spelt starches were evaluated.…
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▼ Gelatinization properties of organic and conventional rice and spelt starches were evaluated. Commercial organic and conventional rice starches were obtained from a supplier. Organic and conventional spelt was planted side by side in six replicated plots in Wooster, OH and the starch was extracted using protease digestion method. Differential scanning calorimetry (DSC) was used to analyze starch gelatinization temperature range. Dynamic rheological measurement was applied to study the changes in complex viscosity and loss tangent during heating. High-performance size exclusion chromatography (HPSEC) was performed to elucidate the starch molecular composition. DSC showed that the organic rice starch had a significantly lower gelatinization temperature range than the conventional rice starch (56-66°C for organic, 60-72°C for conventional rice starch). Rheological analysis displayed similar onset temperatures for both organic and conventional rice starches, but a higher peak temperature for the organic rice starch (65°C and 93°C for organic, 64°C and 91°C for conventional starch). The peak complex viscosity was lower for the conventional (2.8 Pa.s) than for the organic rice starch (5.1 Pa.s), suggesting varying structural properties, such as molecular composition, as confirmed by the HPSEC. HPSEC showed that the organic rice starch contained a lower amylose level and a significantly higher molecular weight of amylopectin. For the spelt starch, DSC showed that the gelatinization temperature range was 57°C - 69°C with a peak temperature of 62°C on average. There was no statistical difference in gelatinization properties between organic and conventional spelt starches. Plot locations were found to be the driving factor of some of the observed differences. Rheologically, no significant difference was observed in the onset and peak temperatures of increase in complex viscosity. Variation in the rheological behavior among different plot locations were more pronounced than that between the two growing conditions. The percent mass fraction of amylose in the spelt starch was in the range of 35.7-54.5%. There was no significant difference in the molecular weight of amylose and amylopectin irrespective of the plot locations. Significant difference was found between the amylopectin Mw of organic and conventional spelt starches when analyzed collectively, which also correlated positively with the gelatinization enthalpy. Therefore, the organic rice starches studied may be used to substitute for the conventional counterpart only along with suitable adjustment in formulation or processing parameters to achieve equivalent products. The organic spelt starches may replace the conventional one when gelatinization behavior is considered.
Advisors/Committee Members: Vodovotz, Dr. Yael.
Subjects: Agriculture; Chemistry; Food Science
Keywords: Gelatinization; DSC; rheology; HPSEC; functional properties; rice starch; spelt starch
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26.
Ilic, Sanja.
Post-harvest Interventions and Food Safety of Leafy Green Vegetables.
Degree: PhD, Food Science and Technology, 2011, Ohio State University
► Foodborne illness outbreaks associated with the consumption of leafy green vegetables are…
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▼ Foodborne illness outbreaks associated with the consumption of leafy green vegetables are a growing public health concern worldwide. While there has been great progress in using practical and cost-effective interventions to reduce the risk of contaminations and prevalence of pathogens on farm, effective post-harvest interventions to remove field acquired contamination are still lacking. The body of literature related to microbial hazards in leafy green vegetables has accumulated since 1990, offering often contradictory information on the efficacy of food safety interventions. In this work, I identified, characterized, and assessed the quality of available research on prevalence, risk factors, and interventions for 16 microbial hazards in leafy green vegetables. Systematic literature review, a replicable two-level relevance screening, and a two-phase quality assessment and data extraction procedure were performed by two independent reviewers following general principles of systematic review methodology. A lack of well designed, executed, and reported prevalence studies on efficacy of intervention(s) under real-life conditions was observed. Additional knowledge gaps and research areas included equipment sanitation and cross-contamination potential, survival of pathogens in organic vegetables, and the lack post-harvest intervention studies applicable to the developing regions. Several identified knowledge gaps were further addressed. The concentration of coliforms and Escherichia coli and prevalence of E. coli O157:H7, Salmonella spp., Shigella spp. and Listeria monocytogenes in spianch before and after minimal processing under commercial conditions was investigated. A total of 1356 spinach samples were collected daily in two processing plants over a period of 14 months. The proportion of coliform positive samples increased from 53% before to 79% after minimal processing. Generic E. coli prevalence was 8.9% (mean 1.81 ± 0.14 log CFU/g) with no difference after processing. Salmonella spp. and L. monocytogenes were isolated from 0.4% and 0.7% of samples, respectively. The contribution of each commercial processing step to generic E. coli, coliform, and total aerobic bacterial load on fresh-cut lettuce and food contact surfaces in a processing plant were further quantified. Plausible bacterial populations on fresh-cut, minimally processed lettuce using T-RFLP analysis were identified. Washing initially decreased coliforms on lettuce but microbial populations increased during subsequent steps. Peak contamination on food contact surfaces was detected after two hours of processing, then declined after 4-6h of processing without intermediate sanitation interventions. No association between coliform increase on lettuce and contact-surfaces was found. Removal of outer leaves was the single most effective step of large-scale minimal processing. T-RFLP analysis identified representatives of 12 phyla/classes of bacteria on minimally processed lettuce. The ability of E. coli O157:H7 to survive in processed packed organic and conventional baby spinach during storage conditions during the shelf life was compared. Epiphytic bacteria present and the effect of leaf size on survival of E. coli O157:H7 were assessed. E. coli O157:H7 survived similarly on both spinach types. Finally, existing data pertaining to post-harvest interventions was compiled and synthesized. The options for post-harvest risk reduction were summarized and the existing information was translated to vegetable production conditions in developing countries. The applicability of multiple-barrier approach in developing regions was discussed.
Advisors/Committee Members: LeJeune, Jeffrey.
Subjects: Food Science
Keywords: food safety, lettuce, vegetables, E. coli, Salmonalla, scoping review, systematic review
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27.
Kottman, Scott David.
Production of an Anthocyanin-Rich Vegetable Juice Concentrate from Cull Red Radishes for Use as a Food Colorant.
Degree: MS, Food Science and Technology, 2011, Ohio State University
► Anthocyanins are widely distributed compounds in nature that serve a dual purpose:…
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▼ Anthocyanins are widely distributed compounds in nature that serve a dual purpose: they produce a wide array of vibrant colors and they possess potent antioxidant properties. The ability to harvest the natural rich colors of anthocyanins as a potential replacement for synthetic dyes such as FDandC Red No. 40 will fulfill the modern consumer’s demand for a more natural and healthful product. Anthocyanins present in red radish skins provide color intensity, under acidic conditions, similar to that of FDandC Red No. 40 and could provide a useful tool for the food industry. Additionally, radish anthocyanins exhibit higher stability than most other anthocyanin extracts. The objective of this work was to harvest an anthocyanin-rich natural colorant from cull radishes, a waste product, in order to produce a high quality product free of undesirable aromas that provides color and added value suitable for food applications. From cull or premium radish skins, the color was extracted by abrasive action or steam to produce a colored juice. Filtration, evaporation, salt and acid addition and heat were evaluated as means of removing undesirable aromas and flavors or minimize their formation during processing. Samples were analyzed using UV-vis spectroscopy, HPLC and sensory analyses. Premium and cull radishes produced very similar products. A chemical extraction of red radish skins yielded 107mg pelargonidin-3-glucoside equivalents (pg-3-glu eq)/100g of skin. Abrasive peeler effectively extracted pigments from cull radishes, salt and acid significantly decreased aroma formation, but created the new challenge of salt removal. Nano-filtration reduced the anthocyanin yield from 83.6mg/100g skin to 72.6mg pg-3-glu eq/100g of skin. Concentration of the juice in a rotary evaporator for 1-10 min helped decrease aroma intensity and produced a juice with 224-206mg pg-3-glu equivalents/L. Steam was effective at safely removing between 25-50% of the anthocyanins from the skins while preventing aroma and flavor formation. A sensory panel found the quality of color to be comparable to FDandC Red No. 40, and found that samples extracted with salt, acid or steam had lower aroma intensity. Despite the lower pigment yields, the steam extraction method was preferred because of its simplicity, and quality of the final product. Additionally, the product being created is from a waste material naturally generated by the radish company. This waste can be turned into a high quality food colorant. Using this resource potentially increases the sustainability of a product and the land by making the end product more cost effective for the business, while providing consumers with a healthy alternative to synthetic dyes.
Advisors/Committee Members: Giusti, M. Monica.
Subjects: Food Science
Keywords: Anthocyanins; Red Radish; Food Colorant
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29.
Lin, Shin-Jie.
Development of Edible Packaging for Selected Food Processing Applications.
Degree: PhD, Food Science and Technology, 2012, Ohio State University
► Edible packaging (coatings and films) has been used to improve the shelf…
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▼ Edible packaging (coatings and films) has been used to improve the shelf life, sensory attributes and nutritional content of food products. The manufacturing process for edible packaging depends on the properties of the ingredients and the application end use. The objective of this study was to optimize the method for commercial-scale chitosan film production. This was done by optimizing the raw ingredient selection, and blending sequence. Quality control tests were used to monitor these include viscosity, the drying rate of the ingredient slurries, film solubility, chemical compositions, as well as the thermal properties of the edible films made during the study. The first part of this dissertation (Chapter 2) focuses on the effects of solvents on the film properties. Edible slurries were prepared by dissolving 1.0-2.0% chitosan in 1.0% food-grade acetic or lactic acids with 0-20% ethanol solutions. Viscosities of the different film formulations were measured using a viscometer, and changes in drying time were determined using a OHAUS Moisture Determination Balance. Solubility of the films was determined by dissolving the dried films in water then measuring the weight changes. The chemical compositions of the polymeric chains were identified by Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) spectroscopy. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were used to characterize changes to the thermal properties of the films as a result of the various treatments. Results indicated that viscosity of the slurries significantly (p< 0.05) increased with increasing chitosan and ethanol concentrations. ATR-FTIR spectra showed that acetic acid/chitosan provided more carboxyl (1442 cm-1) and amine groups (1573 cm-1) within the polymeric network when compared to the lactic acid/chitosan films. The addition of 20% ethanol significantly (p< 0.05) enhanced the drying rate of the film by 30%. However, additional ethanol did not have a significant influence on the solubility and thermal properties of the films. The second part of this dissertation (Chapter 3 and Chapter 4) reports two methods for incorporating vitamin E into the chitosan. Edible chitosan slurries were prepared by blending 250 or 500 mg vitamin E into1.0- 2.0% chitosan. Two blending processes were used to incorporate the vitamin E into the edible slurries: (1) the vitamin E added before lecithin (VE first); and (2) the vitamin E mixed with lecithin (VE mixed) and then added into the slurries. Viscosities of the various formulations, thermal properties, the chemical compositions and solubilities of the film samples were done as mentioned before. High performance liquid chromotagraphy (HPLC) was used to determine the concentration of vitamin E in the films. This study found that vitamin E addition significantly (p< 0.05) affected the rheology of the edible slurries. In addition, viscosity increased with increasing chitosan and vitamin E concentrations. Low chitosan concentrations in the formulation decreased vitamin E incorporating ability, leading to more vitamin E accumulation on the film surface. Solubility decreased with increasing accumulated vitamin E on the film surface. Results also showed that 2.0% chitosan blending with 500 mg VE was superior to the other formulations. More than 73% (368.60± 12.40 mg) of the vitamin E was successfully incorporated in the film. TGA analysis indicated that vitamin E decomposition occurred at 430-450°C. However, DSC thermograms showed no significant difference in glass transition temperature (Tg) and the phase changes in the films.
Advisors/Committee Members: Pascall, Melvin.
Subjects: Food Science
Keywords: edible film, chitosan, vitamin E, thermal analysis, ATR-FTIR
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30.
Lin, Yi-Hsuan.
Volatile changes caused by different factors in different types of chocolate.
Degree: MS, Food Science and Technology, 2010, Ohio State University
► The volatiles change caused by different factors in different chocolate was analyzed…
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▼ The volatiles change caused by different factors in different chocolate was analyzed by using SIFT-MS (Selected Flow Tube-Mass Spectrometry). During conching, all volatiles initially increased then decreased in unsweetened dark (UDC), dark (DC), unsweetened milk chocolate (UMC). The greatest rate of volatile loss occurred during the first 28h of conching. The total volatile lost was 72- 79% at 48h, and loss was mostly due to methanol. The percent lost of acetic acid was least, about 16-61%. Most volatiles lost 80-95% during conching, but a few volatiles had low percent lost. In storage study, unsweetened dark chocolate at 4°C, 25°C, and 50°C had higher total volatile concentration than unsweetened milk. Samples at 50°C showed less loss than at 25°C and 4°C in total volatile. The low loss of Strecker aldehydes, heptanal, and nonanal may indicate the occurrence of the Maillard reaction and lipid oxidation. In blooming measurement, cocoa mass, unsweetened dark chocolate, and dark chocolate were analyzed. Acetic acid in bloomed samples was significant lower than unbloomed in UDC, DC, and cocoa mass (CM). In the real time volatile release test, the volatiles decreased over time before swallowing and maintained a constant level after swallowing. The mouthspace before swallowing to headspace ratio (MSbs/HS) on average were 0.069. The mouthspace before to mouthspace after swallowing ratio (MSbs/MSas) varied from 0.042 to 49 between different types of chocolate and volatiles. Benzaldehyde had the highest MSbs/MSas ratio in cocoa liquor and dark chocolate compared with other compounds. The nosespace to headspace ratio (NS/HS) were varied from 0.0012 to 0.17. No correlation was found between volatile lingering and air-water partition in this study.
Advisors/Committee Members: Barringer, Dr. Sheryl.
Subjects: Food science
Keywords: chocolate; chocolate flavor; SIFT-MS; conching; tempering; storage; eating
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