J. F. Price

Role of triglycerides and phospholipids on development of rancidity in model meat systems during frozen storage

Abstract The effect of triglycerides, phospholipids and total lipids on development of rancidity during frozen storage at −18° C for 8 months was studied using lipid-free muscle fibres in combination with added triglycerides, phospholipids and total lipids. Results showed that added phospholipids greatly increased TBA values. Oxidation took place in two stages. Phospholipids were the first to oxidise, with their rate of oxidation decreasing with time. Oxidation of the triglycerides began only after a prolonged induction period. Results demonstrated that both triglycerides and phospholipids contribute to development of rancidity, although phospholipids make the greatest contribution. The influence of triglycerides on the development of rancidity was shown to depend upon the degree of unsaturation and the length of time in frozen storage. The relationship between oxidation of the polyunsaturated fatty acids (PUFAS) of the phospholipids and development of rancidity was confirmed.

Effect of a proteolytic enzyme produced by Clostridium perfringens upon porcine muscle

Abstract Purified proteolytic enzyme preparations isolated from actively growing cultures of Clostridium perfringens (ATCC 13124—Type A) were added to aseptic porcine muscle and incubated at 37°C. Samples were removed after one, two and four days incubation. The sarcoplasmic and myofibrillar proteins were extracted and subjected to both conventional and SDS-polyacrylamide disc gel electrophoresis to assess the changes due to the enzyme treatment. The enzyme preparation caused little change in the sarcoplasmic protein fraction but caused some proteolysis in the myofibrillar extract. Comparison of the protein profile from muscle incubated with the purified enzyme preparation and that incubated with the actively growing organisms per se showed that the organisms caused more degradation, suggesting that they produced additional enzymes causing proteolysis of porcine muscle.