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The effect of acidification on myofibrillar proteins
1Food Technology Research Centre, Massey University, PO Box 11222, Palmerston North, New Zealand.
Abstract:
Isolated myofibrillar proteins of mutton, beef and chicken were treated with an acidulent to give various pH values and stored at 5°C for 20 h before analysing the proteins using sodium dodecylsulphate polyacrylamide gel electrophoresis. It was found that protein degradation occurred below pH 4·5, with a decrease in band intensity of all major myofibrillar proteins, particularly myosin heavy chain, and the appearance of new bands at approximately 140 and 70 kd. The degradation had an optimum around pH 3·0 and was inhibited by a high temperature pre-treatment or the presence of the endopeptidase inhibitors pepstatin A and leupeptin. Results are discussed in terms of the action of acid proteinase enzymes.
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