A natural milk candy, composed mainly of milk powder, has not been commercially sold in the U. S. market. The milk candy we developed contains calcium and other essential nutrients, which make it a potential food supplement for adults and children. This thesis research was designed to characterize sensory properties of flavored milk candies and to determine the consumer sensory profile driving product acceptance and purchase intent. A descriptive trained panel (n=12) developed a lexicon and evaluated 3 milk candies (plain, chocolate, and coffee) in triplicate using a 15-cm line scale. 335 adult consumers evaluated acceptability of appearance, size/shape, texture, aroma, specific flavor, sweetness, and overall liking of three flavored milk candies. 92 children evaluated acceptability of overall liking of chocolate and plain flavored milk candies. Data were statistically analyzed. A lexicon included aroma notes: buttery, caramel, cheesy, and cooked; flavor notes: buttery, caramel, cooked, and sweet. Evaluations of the flavored milk candies revealed that they were different, based on descriptive sensory attributes. Cheesy aroma, buttery aroma and caramel aroma were discriminating attributes, while sweet and cooked flavors were least discriminating. Chocolate and coffee flavors may be used to mask strong undesirable cheesy and cooked flavor and aroma notes. Taste, specific flavor, overall liking and aroma were critical to acceptance of the products. Different flavors added to the milk candy caused a significant difference in the consumer responses toward sensory attributes evaluated. Acceptance of the three milk candies could be predicted by taste, specific flavor, sweetness, and overall liking. The purchase intent of flavored milk candies was positively influenced by flavor, overall liking, specific flavor and acceptance. Children liked the chocolate flavored milk candy better than the plain one. There were no significant differences in the way children and adults accepted chocolate and plain milk candies. Our survey indicated that consumers would be more willing to buy flavored milk candies enriched with calcium and minerals that promote health benefit. Further consumer sensory studies together with marketing research are needed to confirm the outcome from this study and to warrant the potential of this new product in the US market.

Age-related macular degeneration (AMD) is a physiological condition that affects the elderly, diabetic patients, and leads to loss of vision. There are no effective therapies for AMD. The role of nutrition in preventing AMD is receiving strong scientific scrutiny. Lutein and zeaxanthin have been identified as dietary strategies that can delay the onset of AMD. Consumption of at least six milligrams of lutein per day has been reported to delay the onset of AMD by as much as 43%. However, most available food sources contain such low levels of lutein that it would be difficult to meet the daily requirement. It would require 2 lbs of corn, 16 lbs of tomatoes, or one salad bowl of kale to meet the minimum daily requirement. As a result, food fortification with lutein extract is appealing to health conscious consumers. The objective of this study was to prepare an oil in water emulsion containing at least 6 mg of lutein per serving size (one tablespoon) as a daily source of lutein. Random Centroid Optimization was applied to find the best conditions for preparing a stable emulsion. Experimental parameters included: lutein concentration (0.010-0.020 %w/w); pH (3.5-4.7); phosphatidylglycerol (0.018-0.1 %w/w); whey protein (1.5-3.5 %w/w); and corn oil (15-25 %w/w). Emulsions were prepared and turbidity measurements were determined as a function of half-life stability in minutes. Absorbance was measured at 500 nm for 10 min. The same measurements were carried out using the best values for four factors obtained from the RCO program. Emulsion stability was evaluated by heating samples at 90 oC from 5 to 30 min to check for oil separation. Emulsion samples were also shaken at 700 rpm for 30 min. Size distribution and zeta potential of emulsion droplets were measured, using zetameter. After 9 experiments in the first cycle and 4 experiments in centroid cycle, optimal conditions for the preparation of a stable lutein-enriched emulsion were: corn oil: 20 %, phosphatidylglycerol (0.018 %w/w), pH: 4.55, lutein concentration: (0.015 %w/w), and whey proteins concentration 2%.

Quality deterioration of smoked catfish is caused by lipid oxidation and microbial spoilage. Smoked catfish can be cross-contaminated during processing and may harbor several pathogens, e.g., Listeria monocytogenes, and Salmonella spp. Lipid oxidation causes unpleasant flavor, thus making smoked fish unacceptable. Hydroperoxides and free radicals, formed during oxidation, may directly react with fish tissues to promote complex reactions. Through such complex reactions, physicochemical properties of smoked catfish may be adversely affected. A combination of smoking and treatments with antimicrobial agents and antioxidants would retard microbial spoilage, extend shelf life, and enhance safety of smoked catfish. The objective of this study was to assess microbial and physicochemical quality of smoked catfish (Ictalurus furcatus) treated with antimicrobial agents and antioxidants during 6-week storage at room temperature. Raw catfish steaks were subjected to the following treatments for 30 minutes prior to smoking: 25% NaCl and 1% ascorbic acid; 3% sodium lactate; 3% sodium lactate and 5% rosemary extract; and/ or 5% sorbic acid. The non-treated catfish served as control. Smoked catfish samples were drawn after 0, 2, 4, and 6 weeks for microbial, pH, water activity, proximate, color, thiobarbituric acid reactive substances (TBARS), and peroxide value (PV) analysis. All treated smoked catfish had a water activity (aw) less than 0.85 compared with 0.94 for the control. Total plate count (TPC) for all dried samples was 1.2- 2.2 log CFU/g at day zero and increased to 1.48-3.0 log CFU/g after 4-week storage. The control was moldy after 6-week storage. No mold was observed on samples treated with sodium lactate, or sorbic acid even after 4-week storage. No Salmonella and Listeria monocytogenes were isolated from any smoked samples. Samples treated with 3% sodium lactate had the lowest microbial loads and were shelf-stable up to 6 weeks without refrigeration. The sample treated with rosemary extract was more stable to oxidation than all other treatments. Protein content of smoked sample ranged from 54 to 87%, 2.82 to 5.80% for ash, 13.11 to 22% for fat, and 11 to 22% for moisture. No significant change in color of smoked catfish was observed during storage. Sodium lactate treatment was most efficient in controlling microbial quality and extending shelf life of smoked catfish.

The present work aimed at recovering, purifying, and testing rice cystatin or oryzacystatin I (OCI) bioavailability, to provide scientific evidence that rice cystatin can be used as a functional food ingredient. OCI was extracted from rice bran using 25 mM sodium phosphate buffer containing 0.15 M NaCl at pH 7.0. The resulting homogenate was heat treated, cooled and precipitated with ammonium sulfate. The recovered protein was dialyzed against 50 mM sodium acetate buffer pH 4.8 and sequentially purified by cation exchange, size exclusion, and anion exchange chromatography. Nine hundred and seventy micrograms of protein were obtained from 1 kg of rice bran. SDS-PAGE provided one pure band. MALDI-MS identified the protein at 11,538 Da. Overall there was a 14-fold increase in specific activity throughout the purification process. OCI was hydrolyzed with chymotrypsin in 20 mM sodium phosphate buffer pH 7.4 for 2.5 hours at 37°C at an enzyme to protein ratio of 1:100. The resulting chymotryptic peptides yielded a higher inhibitory activity compared to unhydrolyzed OCI (145% increase). The permeability of OCI and OCI chymotryptic peptides across Caco-2 cells was evaluated for 3 hours at 37°C. Unhydrolyzed OCI did not cross the cell monolayer. OCI chymotryptic peptides were uptaken by the Caco-2 cells, as they were not detected in the apical side of the cells either by MALDI MS or papain inhibitory activity assay. After three-hour incubation, only one peptide with a molecular weight of 5.8 kDa was detected in the basolateral side of the cells. The peptide that crossed the basolateral membrane had no inhibitory activity versus papain. The significance of these findings and future research direction will be discussed.

An efficient procedure was developed and used to extract and purify isoflavones from defatted soy flour. The purity of the final product reached 94%. The antioxidant activities of soybean isoflavones (genistein and daidzein purchased from Sigma Chemical Co, and a mixture of isoflavone glycosides extracted from defatted soy flour) were investigated by a cholesterol oxidation model accelerated by 2,2-azobis(2-methylpropionamidine) dihydrochloride (AAPH). All components exhibited very high antioxidant activities in the inhibition of cholesterol oxidation. Genistein had higher inhibition to the formation of 5,6beta-epoxycholesterol (5,6b-EP) and 7-ketocholesterol (7-keto), while no significant difference was found between the antioxidant activities of daidzein and genistein against cholesterol oxidation to 7beta-hydroperoxycholesterol (7b-OOH) and 5,6alpha-epoxycholesterol (5,6a-EP). The glycosides mixture had characteristics similar to genistein and daidzein in preventing cholesterol oxidation, but the glycosides mixture was found to have lower antioxidant activities compared to aglycones. The biological activities of genistein and daidzein to affect cellular response in SVEC4-10 mouse endothelial cells to t-butyl hydroperoxide-induced oxidative stress were also evaluated. Genistein had higher cytotoxicity than daidzein to SVEC4-10 cells and none exerted discernable antioxidant activities in this cell culture model. The antioxidant activities of soybean isoflavones may contribute to their potential role in reducing the formation of certain types of cancers, so daidzein might be a more appropriate cancer preventive neutraceutical because of its lower cytotoxicity. In view of the high cytotoxicity, this cell culture model might not be suitable for the study of antioxidant activity of soybean isoflavones. Some modifications or another cell culture model is needed in order to further this study of antioxidant activity. Defatted soy flour is a by-product of oil extraction, so the antioxidant activities of soybean isoflavones could improve the utilization of the by-product and benefit the soy industry.

Health benefits from consuming rice bran oil (RBO) have been extensively studied in humans. RBO has been shown to decrease cholesterol absorption by inhibiting the oxidation of the LDL-cholesterol. Gamma-Oryzanol is one of the RBO components that possess antioxidative properties; it is a polyphenolic compound resembling tocopherol (vitamin E), which is another component of RBO. There are evidences that oryzanol has potential applications for enhancing shelf-life of foods containing fats processed at a high temperature, decreasing the total cholesterol, LDL-cholesterol and triglyceride levels in plasma lipids, and healing ulcers. In order to take advantage of the health benefits of oryzanol, food products fortified with oryzanol should be developed and characterized. Cheddar cheese containing Gamma-Oryzanol was developed, and the effects of oryzanol on cheese quality during ripening process were studied. Cheese was stored for 5 months and drawn every month for quality evaluation of color, texture, microbial growth, aroma development, bacterial identification by polymerase chain reaction, oryzanol retention, moisture content and free fatty acid profile. The consumer acceptance was evaluated after 5 months of maturation. The results indicated that by adding Gamma-Oryzanol to cheddar cheese changes occurred in the quality, but, they were not significant when stored for up to 4 months, and the Gamma-Oryzanol was well retained. Consumers were able to differentiate the cheddar cheese containing Gamma-Oryzanol from the control containing no Gamma-Oryzanol. Overall appearance, texture, taste and hardness were the most discriminatory sensory attributes. There was a significant positive increase 0.13 to 0.30 times higher in the purchase intent of cheddar cheese containing Gamma-Oryzanol after consumers had been informed about the health benefits of oryzanol. Overall liking was the attribute critical to purchase intent and the most important attribute that changed the acceptability of the cheese. Consumers preferred the cheese with Gamma-Oryzanol less than the control but were willing to buy it and compromise the overall liking of cheese merely to get the health benefits of the product. Further studies need to be done to determine the direct effects of cheddar cheese containing Gamma-Oryzanol in human health, and to optimize the homogenization and fortification of Gamma-Oryzanol when incorporated in cheese products.

Rice bran oil (RBO) has been considered healthy cooking oil with potent effects to reduce the risks of atherosclerosis and coronary heart disease. The relatively high level of unsaponifiable components contributes to the healthy benefits of RBO. This study investigated the possibility that the cholesterol-lowering effects of oryzanol are through increased fecal steroid excretion. The objective was to compare fecal cholesterol and bile acid excretion as well as bioavailability among different forms of oryzanol. The correlation between bioactivity and bioavailability of oryzanol was investigated as well. Forty-seven female breeder rats were used as animal models. Oryzanol was added to an AIN-93 M maintenance diet at 2.8g/kg as the treatments. Treatments were either oryzanol in RBO, dissolved oil form of oryzanol in corn oil, or crystalline form of oryzanol added directly to the diet. Control was corn oil. Fecal samples were collected at week 6 and 10. Fecal cholesterol, oryzanol, and bile acids were analyzed with GC-FID. Results showed no significant differences between the two collection periods (P>0.05). Oryzanol in RBO produced the greatest fecal cholesterol excretion among the diet groups (P<0.05). Both fecal cholesterol and total bile acid excretion were significantly higher in rats fed RBO oryzanol than the average of the other two treatment groups (P<0.001). It may indicate that the hypocholesterolemic activity of RBO with oryzanol was more effective than oryzanol in corn oil, through synergistic effects of the components in the unsaponifiable contents. The possible mechanism for RBO and oryzanol to lower cholesterol levels appeared to be through inhibiting cholesterol absorption and bile acid reabsorption to enhance fecal cholesterol and bile acid excretion. The effect of treatment compared to control was greater for bile acid excretion than for cholesterol excretion, which may suggest the primary mechanism of the hypocholesterolemic effect of oryzanol may be through the interference of bile acid reabsorption in the enterohepatic circulation. The correlation among different forms of oryzanol to the bioactivity was unclear, although the results showed fecal recovery of oryzanol was positively related to fecal steroid excretion. It might indicate the absorbability of oryzanol was negatively related to fecal steroid excretion.

Rice is an important commodity in Louisiana and throughout the world. During the milling process, about 15% of rice kernels become broken. Louisiana produced approximately 2,011,000 hundred weights of broken rice kernels in 2002. Converting broken rice into rice-based products adds dollars back to broken rice. The market potential for rice in processed foods is huge. In the refrigerated and frozen baked foods category, it is approximately $14.3 billion; while in the baked snack foods and wholesale bakery foods category, it is approximately $31.4 billion. Approximately 1-2% of the United States population suffers from Celiac Spruce Disease, which is a result of the malabsorption of certain proteins in the diet, specifically gluten. Gluten can be found in almost all cereal grains, including wheat, rye, oat, and barley. Rice, however, does not contain gluten, which makes it an ideal food for individuals with this disease. A butter cake product was formulated using predominantly rice flour. Consumer studies were performed to determine 1) attributes critical to product acceptance and purchase decision, 2) the optimal formulation of the butter cake product, and 3) whether or not consumers were able to correctly differentiate between butter cake samples made either from wheat, rice, or a mixture (50:50) of wheat and rice. Logistic regression analyses identified overall liking, taste and texture as attributes critical to overall acceptance and purchase decision. Predictive discriminant analysis also identified if overall liking, taste, moistness, and texture contribute significantly to overall differences among the three butter cake formulations. Superimposition of the optimal response surface areas of overall liking, taste and texture revealed that formulations containing 50-95% wheat, 0-50% rice and 0-40% pre-gelatinized rice flours would yield a product with acceptability scores greater than 6.0. Consumers were able to correctly discriminate between the different formulations of butter cake (100% rice flour, 50/50 wheat/rice flours) when compared to the labeled control formulation containing 100% wheat. Consumers would be willing to compromise certain attributes in order to gain a potential health benefit from consuming this product, especially if they are not able to consume wheat products.

Chitosan is made from chitin by a chemical process involving demineralization (DM), deproteinization (DP), decolorization (DC), and deacetylation (DA). Very little work has been done to demonstrate the effects of altering or excluding any of the processing steps on chitosan characteristics. The present study was undertaken to evaluate the effects of process modification during chitosan production on the physiochemical and functional properties of crawfish chitosans. Five experimental chitosan samples (DCMPA, DMCPA, DMPCA, DMPAC, DAMPC) prepared with modified processing protocols and the control (DPMCA - traditional chitosan production process) were evaluated and compared with the two commercial crab chitosans. All samples were subjected to physicochemical (moisture, nitrogen, and ash contents, degree of deacetylation, molecular weight, viscosity, solubility, bulk density, and color) and functional (water binding capacity, fat binding capacity, emulsion capacity, and emulsion viscosity) characteristic analysis. Three experimental replicates were performed with a duplicate analysis of each sample. Results indicated that process modification of crawfish chitosan production yielded some differences on each characteristic compared with the control and commercial chitosans. For instance, changing the sequence of DC for the production of crawfish chitosan affected its properties. DCMPA and DMCPA resulted in an increase in molecular weight and ash, respectively. In contrast, DMPCA led to lower viscosity. The most notable change observed with the DMPAC chitosan was a light brown degraded colored chitosan that exhibited properties of a weak polyelectrolyte. When chitosan process started with DA, a very poor of yield were obtained. When DM and DP were reversed during production, the results showed some difference, e.g., the lower viscosity, higher fat binding capacity, and higher emulsion viscosity of DMPCA over DPMCA. This study demonstrated that process modification of crawfish production affected physicochemical and functional properties. The optimal chitosan production may vary depending on the intended final usages in food systems as demonstrated by functional properties from this study.

The effects of plant source cooking oils on cholesterol oxidation during heating in cholesterol standard and salmon meat model were investigated. A GC-MS system was used to identify and quantify of cholesterol and cholesterol oxidation products. The capabilities of different plant source cooking oils in preventing cholesterol oxidation were compared. Commercial plant oils used in this experiment included corn oil, canola oil, olive oil, soybean oil, and rice bran oil. Two lab prepared crude soybean and rice bran oils were also used in this study to evaluate their capabilities of preventing cholesterol oxidation. The tocopherols and tocotrienols antioxidants in those oils were measured by a HPLC system as well. In both cholesterol and salmon meat models, it was found that the cholesterol level decreased with increasing heating temperature and time. The cholesterol decreasing in the salmon meat model was not as fast as in the cholesterol model. Ketocholesterol was the major cholesterol oxidation product in the two models. Soybean oil had the highest capability in preventing cholesterol oxidation, while rice bran oil had the lowest capability among these oils. The soybean oil had the highest alpha and gamma-tocopherol levels, which were considered to be the major antioxidant components of preventing cholesterol oxidation. The commercial oils had lower level of tocopherol and tocotrienol than the lab prepared oil due to the loss of those antioxidants during oil refining procedures. The different capacities between lab prepared soybean oil and rice bran oil in salmon samples were not as significant as in cholesterol model since the salmon meat may contain antioxidants in itself and reduce the total amount of cholesterol oxidation.