Oxidative Stability of Restructured Beef Steaks Processed with Oleoresin Rosemary, Tertiary Butylhydroquinone, and Sodium Tripolyphosphate

Antioxidant activities were evaluated in raw restructured beef steaks stored at ?20°C six months and in cooked steaks at 4°C six days. During refrigerated storage, thiobarbituric acid-reactive substances (TBARS) and sensory scores indicated sodium tripolyphosphate (STPP) provided (p<0.01) protection against warmed-over flavor development. No significant differences existed between OR (0.10%)/STPP and TBHQ/STPP, due probably to STPP. During frozen storage, a linear concentration effect of OR existed (p<0.01) for both TBARS values and sensory scores indicating OR was an effective antioxidant which combined with STPP produced an additive protective effect during frozen storage. Hexanal content and phospholipid fatty acid profiles also changed during frozen storage. Correlation coefficients between TBARS values and sensory scores were generally nonsignificant.     

Effects of Frying Procedures and Compositional Factors on the Temperature Profile of Bacon

The effects of frying procedures (preheated vs cold skillet) and compositional factors (adipose vs lean) on the final temperatures attained in fried bacon were investigated as a prelude to studying the kinetics of N-nitrosopyrrolidine formation in bacon. With a preheated skillet set at 171°C, the final temperature reached in whole bacon samples at the end of the 6 min frying time was 164 ± 3°C. Bacon samples, initially placed in a cold skillet preset to heat to 171°C, attained temperatures of 127 ± 5°C and 165 ± 6°C at the end of 6 and 8 min frying periods, respectively. It was observed that the lean bacon strips rarely exceeded 145°C while the adipose approached 165°C when separated adipose and lean components from whole bacon samples were fried for 6 min in a preheated (171°C) skillet.     

Effects of Dietary Antioxidants and Oxidized Oil on Membranal Lipid Stability and Pork Product Quality

The effects of dietary tocopherol and oxidized oil on the oxidative stability of membranal lipids in pig muscles and on the oxidative stability of pork products during refrigerated and frozen storage were evaluated. Membrane-bound α-tocopherol stabilized the membranal lipids and reduced the extent of lipid oxidation occurring in pork patties and pork chops during storage. Oxidized dietary oil had an adverse effect on the stability of both the membranal lipids and pork products. The addition of salt to the pork patties accelerated the oxidative process when the patties were stored under fluorescent light and in the dark.     

EFFECT OF DIETARY VITAMIN E AND SURFACE APPLICATION OF OLEORESIN ROSEMARY ON IRON/ASCORBATE-STIMULATED LIPID OXIDATION IN MUSCLE TISSUE AND MICROSOMES FROM RAINBOW TROUT (Oncorhynchus mykiss)

The effect of dietary α-tocopheryl acetate and surface application of oleoresin rosemary on iron/ascorbate-induced lipid oxidation in rainbow trout ( Oncorhynchus mykiss ) muscle and microsomes was investigated. The 2-thiobarbituric acid-reactive substances (TBARS) values of muscle and microsomes isolated from fish fed the higher concentration of α-tocopherol (500 mg/kg feed) were smaller than those of fish fed the lower concentration (100 mg/kg feed). The protective effect of oleoresin rosemary on lipid oxidation in fish muscle was also observed. Analysis of variance revealed a significant (p < 0.01) interaction between dietary treatments and incubation time. Dietary α-tocopherol supplementation significantly increased the α-tocopherol concentration of muscle microsomal membranes, thereby increasing the oxidative stability of the membrane lipids.     

Effects of Dietary Oils and α-Tocopherol Supplementation on Membranal Lipid Oxidation in Broiler Meat

The effects of different dietary oils and α-tocopherol on the fatty acid composition of mitochondrial and microsomal lipids of broiler muscle and their lability to NADPH-induced peroxidation were investigated. Fatty acid composition of both neutral lipids and phospholipids of mitochondria and microsomes was influenced by dietary oil composition. Supplementation of the diet with α-tocopherol only appeared to increase the α-tocophcrol concentration in the microsomal membranes in the dark meat. The rate of NADPH-induced lipid peroxidation in microsomes and mitochondria was dependent primarily on the fatty acid composition of the membrane lipids, and, to a lesser extent, on the α-tocopherol content.     

Distribution of Cholesterol in Fractionated Beef Tallow

The cholesterol contents of tallow and tallow fractions derived by aqueous detergent fractionation were determined by gas chromatography. Tallow was found to contain 0.14% cholesterol by weight. Liquid and solid fractions subsequently derived by temperature fractionation at 40, 33, 27, 22 and 18°C contained between 0.10 and 0.15% cholesterol by weight. The liquid fraction at each temperature had cholesterol contents 0.02 – 0.04% higher than the corresponding solid fractions.