The relative sweetness, flavor, texture and overall acceptance of sucrose and fructose was determined at various sugar levels in sugar cookies, white cake, vanilla pudding and lemonade. Because of the reported increased sweetness of fructose and its increased tolerance in individuals with diabetes mellitus, the study was designed to investigate the possibility of fructose as an alternative sweetener. Taste panel members were used to evaluate the products. All products were served in duplicate and only data from those judges who had sampled both replications were used for the statistical analysis. Each product was prepared at 100%, 50% and 25% of the specified recipe quantity, using three different sugars: sucrose, fructose equal to sucrose by weight and fructose equal to sucrose by volume. A second objective of this study was to determine if quantities less than suggested in traditional recipes for either sugar could be used without damaging product acceptability. The results of this study indicated that sucrose was both preferred and considered sweeter than fructose in sugar cookies, however; the reverse held true in lemonade. Based on the results of this study the author does not recommend that individuals substitute fructose for sucrose. In addition to panels comparing sucrose and fructose in baked products, the difference in diabetic and non diabetic taste sensitivity was also evaluated. Detection and recognition thresholds were determined for diabetic and non diabetic youth (19-15 yrs.) and adults (16 yrs. and older) for sweet, sour, salty and bitter taste stimuli. Diabetics showed a lower sensitivity, especially in older individuals, with the exception of sour stimuli. As previously reported, detection thresholds were lower than recognition thresholds. The youth groups were better able to detect the presence of stimuli at lower levels than the adult groups, however, they were not as good at recognizing the stimuli.

Sporadic problems with pink color defect, or pinking, has occurred in cooked meat products for decades. Pink color can be due to the presence of undenatured myoglobin, denatured globin hemochromes, or nitrosylhemochrome. This research documented the level of added nitrite that produced nitrosylhemochrome in processed meat rolls from fabricated beef round, pork shoulder, turkey breast, and chicken breast. For each meat type, preliminary studies were conducted to narrow the range at which added nitrite caused pinking. Subsequently, the nitrite levels were increased incrementally by 1-ppm, and pink color was measured by trained panelists and by a Hunter color meter. Nitrosylhemochrome content was determined by acetone extraction. Panel and instrumental measurements identified pink color in beef samples formulated with 14-ppm nitrite; nitrosohemochrome extracts detected pigment at 12- ppm. Nitrite levels that caused pinking in pork shoulder were much lower than in beef. Panelists identified pink color at 4-ppm nitrite, and Hunter color meter values showed increased redness at 6-ppm. Pigment extraction detected nitrosylhemochrome at 4- ppm added nitrite. The trained panel and Hunter color meter detected pink color in turkey breast at 2-ppm added nitrite; nitrosohemochrome extraction detected pink pigment at 3-ppm added nitrite. In chicken breast, pink color was detected visually and instrumentally at 1-ppm added nitrite. Pigment extraction detected nitrosylhemochrome at 2-ppm added nitrite. Lower levels of nitrite (1-3-ppm) caused pinking in light-colored meats (turkey and chicken breast, meats with total pigment between 19-ppm and 27-ppm). Higher levels of nitrite (5-14-ppm) caused pink color defect in dark pigmented meat (beef round and pork shoulder, meats with total pigment levels between 56-ppm and 147-ppm). Regression analysis was used to relate total pigment and the minimum level of nitrite causing pinking. The minimum nitrite level causing pinking was the lowest level of nitrite at which the trained panel, acetone extraction, and instrumental results detected pink color or nitrosyl pigment. The formula obtained from the model was as follows: Y = 0.092X + 0.53, where "Y" is the minimum level of added nitrite to cause pinking and "X" is the total pigment of the meat. This formula can be used to estimate the level of nitrite that can be expected to cause pinking in a wide range of pigmented meats.

Protein quality in freeze-dried skimmilk (SM), regular cottage cheese (RCC), retentate (Ret) and cottage cheese made from ultrafiltrated skimmilk (UFCC) were evaluated by chemical (amino acid score) and biological methods. Biological evaluation was at 5, 8 and 11% protein level in growing rats by measuring biological value (BV), net protein utilization (NPU) and nitrogen efficiency for growth (NEG) over a 14-day period. A 28-day protein efficiency ratio (PER) was determined on the same products at 10% protein level. Effects of added lactose on PER of retentate, regular and UFCC were also evaluated. The most limiting amino acids were cystine + methionine. Amino acid score for Animal Nutrition Research Council (ANRC) reference casein, SM, RCC, Ret and UFCC was 0.72, 0.91, 0.87, 0.91 and 0.98 respectively according to Food and Agricultural Organization/World Health Organization (FAO/WHO) pattern and 0.45, 0.56, 0.54, 0.57 and 0.61 respectively according to whole egg pattern. PER was 2.7, 3.0, 2.7, 3.1 and 2.8 for ANRC reference casein, SM, RCC, Ret and UFCC respectively. PER for retentate and skimmilk were significantly different from the cottage cheese. No significant difference in protein quality was obtained when the products were fed at 5, 8 and 11% levels. Average BV was 93, 91, 91, 95 and 94 for ANRC reference casein, SM, RCC, Ret and UFCC respectively. Average NPU was 87, 84, 83, 85 and 85 for ANRC reference casein, SM. RCC, Ret and UFCC respectively. Average NEG values were 66, 73, 70 77 and 73 for ANRC reference casein, SM, RCC, Ret and UFCC respectively. PER values were 2.7, 3.0, 2.7, 3.1 and 2.8 for ANRC reference casein, SM, RCC, Ret and UFCC respectively. Addition of lactose to a level equal to that in skimmilk reduced the PER value of RCC, Ret and UFCC by about 4%, 6% and 4% respectively. Though no significant difference in protein quality of the products were obtained, there was a tendency of ultrafiltration to increase protein quality.

Two separate experiments were used to investigate iron bioavailability of mechanically-deboned meats using hemoglobin regeneration to measure iron utilization. In both studies, male weanling rats were made anemic by bleeding and being fed a low-iron diet. Experimental diets were control fed to the animals and final hemoglobin concentrations were recorded. Animals were sacrificed and liver iron concentrations determined. The first experiment measured the iron bioavailability of mechanically-deboned and hand-deboned beef plate was better utilized by rats than the iron from mechanically- deboned shank and mechanically-deboned plate. The effect of lipid source and level on iron bioavailability of mechanically-deboned turkey meat was investigated in the second experiment. Fat from the meat was extracted before individual diets were prepared. Four lipids (corn oil, pork fat, turkey fat, or beef tallow) at three different levels (12%, 24%, or 36%) served as dietary fat sources, the effect of lipid dietary fat source and level on iron utilization was found to be negligible.

Residual rennin in cheese whey and curd was measured by using a special sensitive substrate. The substrate was made by reconstituting 6 g NDM in 500 ml of buffer containing 0.2 M CaCl2, 0.5 M cacodylic acid and 0.2 M triethanolamine at pH 5.7. Cheese curd was blended into a 1:7 slurry (1 part curd, 7 parts water), and 1.67% sodium chloride was added to the why and slurry to liberate residual rennin from casein. The residual rennin in cheese whey and slurry were determined simultaneously with an identical sample containing known rennin activity. Samples with known activity were prepared by destroying the residual rennin in unknown samples after which a known amount of rennin was added back to a standard. The examine the effectiveness of this method for measuring rennin activity in whey or slurry, a recovery test was developed to measure rennin activities in the whey and curd made by centrifuging rennet-coagulated milk. The average total recovery from 15 replications was 101.6 ± 2.4%. It was found that pH was a main factor affecting rennin distribution between whey and curd. The amount in the curd increased with decreasing pH at setting. Adding 0.02% CaCl2 to milk was of little effect. The results showed that 68.1 6 ± 6.6% of the residual rennin was found in Cheddar cheese whey after dipping and 17.2 6 ± 2.6% of the residual rennin was in the curd after milling.

A process which incorporates whey sol ids, primarily protein, into cheese to increase cheese yield and eliminate whey handling problems was evaluated. Whey was concentrated by ultrafiltration to levels of 9.8 to 20.3 percent total solids (4.3 to 7.1 percent protein), heated at 70 C for 30 minutes and added to cheese milk with the coagulating enzyme. Increase in cheese yield, on the basis of 39 percent moisture, for 10 pairs of samples was 4.0 ± 2.8 (S.D.) percent. This increase was significant at alpha less than 0.001. Moisture and protein content increased while fat content decreased. Setting time and pH also decreased. Body/texture evaluation showed no change, but flavor scores decreased. Specific defects responsible for changes in flavor and body/texture were identified.

Many innovations have been attempted to shorten drying time or improve dehydration techniques for foods. Despite the recent advances in science and technology the bulk of dried fruit production throughout the world, over 1 1/2 billion tons (dry basis), is prepared by the energy of the sun (Copley and Van Arsdel, 1964), However, other techniques and processes for food dehydration and preservation are occupying more prominent positions in the overall production of dehydrated foods, particularly in the more advanced countries. Economics notwithstanding, it is readily apparent that dehydration as compared to sun-drying offers at least two main advantages. It is more sanitary and it is independent of inclement weather and thus of geographies. These two reasons arc perhaps among the chief ones for the increasing technical developments in dehydration by procedures such as cabinet drying (Beavens, 1944), vacuum drying (Schroeder and Schwarz, 1949), freeze drying (Lawler, 1963) and foam-mat drying (Morgan and Ginnette, 1960). They are perhaps also the reason for continuing research on new and improved dehydration processes which may be adaptable to certain types of products. In this continuing search, electromagnetic waves, which are similar to the more familiar light or radiowaves but differ in frequency and wavelength, have received little attention.

Environmental samples from food processing facilities and production (farms) were taken and analyzed for the presence of indicator organisms and Salmonella spp. on food contact (FC) and nonood contact (NFC) surfaces. Salmonella was isolated from both FC and NFC surfaces of a fruit and catfish-processing plant environment, but not from a dairy processing plant or from produce packaging facility environments. Scatter plots did not show a relationship between indicator organisms and the presence of Salmonella in processing environments, regardless of the facility/environment. Salmonella ser. Gaminara and Salmonella ser. Give were prevalent in the fruit processing environment. Persistence could not be determined, as Salmonella was not detected during subsequent samplings. Two modifications of the Rappaport Vassiliadis (RV) enrichment step were evaluated and compared to the standard enrichment methods for the recovery of Salmonella. Detection rates ranged from 10.2% to 21.2% and 22.3% to 31.9% for aquaculture and sweet potato farming environments, respectively. Salmonella ser. Newport and Salmonella ser. Javiana were prevalent in the sweet potato farming environment, whereas Salmonella ser. Newport and Salmonella ser. Hartford were prevalent in the aquaculture environment. PFGE analysis revealed clusters with a high degree of genetic similarity (greater than or equal to 90%) from the fruit-processing, aquaculture, and sweet potato environments, suggesting that they represented the same strain isolated from different sampling points. Molecular characterization of isolates revealed potential contamination paths to catfish and sweet potatoes.

Oats are considered to be a highly nutritious breakfast food available to consumers. Heightened consumer interest in functional food products and advances in human nutrition have led to increased levels of interest in the development of new oat based products (Webster and Wood 2011). Developments in technology have led to manufacturing of instant oatmeal, making the product more convenient to consumers. Low moisture extrusion processing is one of the most widely used methods to produce ready to eat breakfast cereals; however, there has been little research carried out to determine if high moisture extrusion methods would be viable. This study evaluated the economic and technical feasibility to utilize high moisture extrusion processing to produce ready to eat oatmeal. A process economics evaluation included measuring the capital requirements to implement the system, process costing to estimate the weighted average unit cost, and net present value of high moisture extrusion production. The capital expense was significantly high. However, the unit cost is comparable to similar products in the market. The net present value of implementing the technology revealed a significant profit over the course of 20 years. Six different technical experiments were performed using a twin screw extruder, each experiment testing for the effect of different extrusion variables on finished product texture. Reference texture data was measured using a control product currently made in the industry using an alternative batch process. The processing parameters which seemed to have the biggest influence on product quality were high rates of water injection, low feed rate, high reaction zone temperature, reduction of particle size, and the use of functional ingredients in the formula. Technical hurdles such as low dwell times, steam plugging, and inconsistent feeding prevented complete starch gelatinization and the steady state of extrusion. Overall, the high moisture methodology did not yield product quality that was consistent and cannot be recommended for use.

There is considerable interest among food manufacturers to incorporate protein into food products in both developed and developing countries. Dairy proteins are excellent choices for many different applications, as they are known to have several nutritional and functional benefits. Membrane filtration techniques are often utilized as the preferred method of fractionation, due to the high throughput and continuous nature of the process. One such product produced from membrane filtration of skim milk is called milk protein concentrate. This product is valued for its high protein content, but it has historically exhibited poor solubility when reconstituted into water, which severely restricts the food applications for which it is suitable. There is some existing evidence that milk protein concentrates which contain elevated levels of sodium exhibit higher solubility upon reconstitution into water. The main objective of this thesis project was to demonstrate the effect of sodium chloride, added to diafiltration (DF) water utilized during the manufacturing process, on the solubility of milk protein concentrate. It was observed that the addition of sodium chloride into diafiltration water at levels of 50 mM, 100 mM, and 150 mM had a beneficial effect on the solubility of milk protein concentrate across a variety of reconstitution conditions. For example, when milk protein concentrate was mixed for 1 h on a stage mixer at 23 °C ± 1 °C, a significant increase (p < 0.001) in mean solubility was observed when at least 50 mM NaCl had been incorporated into DF water. The incorporation of 50 mM NaCl into DF water significantly increased (p < 0.001) the mean solubility of milk protein concentrate from 59.81 % to between 64.34 % and 71.78 %. The addition of 100 mM NaCl significantly increased (p < 0.001) the solubility to between 88.80 % and 96.24 %, and the addition of 150 mM NaCl significantly increased (p = 0.005) the solubility to between 92.79 % and 100 %. Minerals analysis of dry powders revealed a significant increase (p < 0.001) in levels of sodium. The addition of 50 mM NaCl into DF water was associated with a significant increase (p < 0.001) in powder Na content to between 2.48 mg/g and 7.44 mg/g. The addition of 100 mM NaCl into DF water was associated with a significant increase (p = 0.002) in powder Na content to between 5.80 mg /g and 10.75 mg/g, and the addition of 150 mM NaCl into DF water was associated with a significant increase (p = 0.001) in powder Na content to between 9.57 mg/g and 14.53 mg/g. A significant difference (p < 0.001) in magnesium level was also detected. Differences in calcium content were not found to be statistically significant (p = 0.016) at α = 0.01. Preliminary observations of milk protein concentrate upon reconstitution were made using a confocal laser scanning microscopy method. This method showed evidence of possible differences in powder particle rehydration and affinity for lipid association between powder particles manufactured at different treatment levels. As the level of NaCl incorporated into DF water increased, particle structures upon rehydration appeared more porous, and the incidence of lipid material that was not associated with powder particles appeared to increase. Overall, this study demonstrates the importance of sodium content in determining the solubility of milk protein concentrate.