The effects of freezing rates on the physico-chemical changes of beef during frozen storage at -20deg C
1988
Kim, Y.H. | Yang, S.Y. | Lee, M.H. (Korea Food Research Inst., Seoul (Korea R.). Food Science and Technology Lab.)
In order to study effect of freezing rates on the quality changes such as pH, TBA value, free fatty acids and protein extractability, cylindrical chopped beef logs with 10cm of diameter and 10cm of height were frozen at three freezing rates (0.97cm/hr, 2.05cm/hr, 3.71cm/hr) using air blast freezer. Physico-chemical changes of frozen meat were investigated during frozen storage at -20deg C for 16 weeks. Results on pH change showed 0.1-0.2 unit increase at the 16th week of the frozen storage and the change was smaller with the increasing freezing rates. Free fatty acids content and TBA value also increased during frozen storage, but they were minimal at 3.71cm/hr freezing rate. Correlation coefficient between TBA value and free fatty acids content were highly significant (r=0.804). After 16 weeks of storage, extractibilities of salt soluble protein decreased by 17.7%, 6.1%, 1.6% at freezing rates of 0.97, 2.05 and 3.71cm/hr, respectively. On the other hand, extractabilities of water soluble protein decreased by 26.0%, 21.2% and 18.5%, respectively. The effect of freezing rates on the protein extractability appeared to be greater in salt soluble protein than in water soluble protein, but freezing denaturation was more rapid in water soluble protein
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