ALPHA-TOCOPHEROL EFFECTS ON COLOR AND SENSORY CHARACTERISTICS OF GROUND PORK DURING RETAIL DISPLAY

To assess the effects of a-tocopherol addition on lipid and pigment oxidation of ground pork, 10, 100 or 1000 ppm was added directly to ground pork in a food grade carrier (2% Medium Chain Triglyceride Oil) then pork was overwrapped with polyvinyl-chloride film and displayed at 4C for three days. Addition of α-tocopherol to ground pork had limited effects on color and sensory characteristics. Display time and light present during display had detrimental effects on a* value, total color, red color contributed by oxymyoglobin, percent of myoglobin, metmyoglobin and oxymyoglobin, visual red and grey colors.     

Sodium Lactate/Sodium Chloride Effects on Aerobic Plate Counts and Color of Aerobically Packaged Ground Pork

Ground pork (15% fat) was formulated to contain 0% to 3.0% sodium chloride and/or 0% to 3.0% sodium lactate (SL) resulting in 28 treatment combinations. Five replications consisted of two with low initial microbial loads (< 10³ CFU/g) and three with high initial loads (> 10⁵ CFU/ g). Ground pork (454g) was overwrapped in PVC and stored (4°C) aerobically for 21 d. A significant salt × SL interaction existed for redness of samples with low initial aerobic plate count (APC). Red color was best preserved by 2.0% or 3.0% SL. Initial pH values of low and high initial APC samples were similar. Initial product pH was best maintained by higher SL levels in low initial load samples and by higher sodium chloride levels in high initial load samples. Samples containing 3.0% SL had the lowest APC regardless of salt level.     

The determination of isolated soybean protein in raw and pasteurized meat products

Sodium dodecyl sulfate-polyacrylamide gel electrophoresis was used to determine the isolated soy protein content in raw and pasteurized meat products. This method determined soy protein (±0.5%) by using an internal standard protein (haemocyanin) to compensate for variations in the meat. The detection limit for meat products was 0.5%. Several possible meat and non-meat interferences were examined and none were found to interfere. The assay cannot be used on retorted products.     

SPINNING DISC MEASUREMENT OF TWO-STAGE CLEANING OF HEAT TRANSFER FOULING DEPOSITS OF MILK

The efficient and effective cleaning of milk protein – based deposits from heat transfer equipment is essential in the dairy industry. The aim of this study was to evaluate the effectiveness of two‐stage cleaning using acid and caustic. Stainless steel discs were fouled during heat transfer by skimmed milk and whey protein. The discs were then cleaned with acid and sodium hydroxide solutions under controlled mass transfer conditions using spinning disc techniques. The use of 0.5% nitric acid, and a commercial acid known as Triplex, as a rinse before caustic cleaning increased the cleaning rate by 2.5 times. The foulant was found to swell about 40% and calcium was leached out within 5 min after exposure to acid. The acid treatment is believed to cause a reduction in the viscosity, and hence an increase in dissolution, of the gel layer formed when caustic cleaning takes place.     

QUALITY AND SWEETNESS OF BAKED CUSTARDS MADE WITH LACTOSE-REDUCED MILKS

Lactose concentrations of lactose-reduced and hydrolyzed lactose-reduced milk (12.1, 4.9 g/L milk, respectively) were significantly lower (p < .05) than the lactose concentration in the control (1% milkfat) milk (38.4 g/L milk). Lactose concentrations in custard mixes made from lactose-reduced and hydrolyzed lactose-reduced milks (6.8, 3.2 g/L mix, respectively) were significantly lower (p < .05) than the lactose concentration in the control custard mix made from 1% milk (29.9 g/L mix). Consumers ranked the lactose-reduced milk and the hydrolyzed lactose-reduced milk significantly higher in sweetness than the control milk. No differences in sweetness between the control, lactose-reduced, and hydrolyzed lactose-reduced baked custards were perceived. Firmness, color, syneresis, and water activity did not differ (p > .05) among the control, lactose-reduced, and hydrolyzed lactose-reduced baked custards.