Changes in Soluble Protein and Actomyosin during Chilled and Frozen Storage of Tilapia (Oreochromis mossambicus)

摘要

The changes in characteristics of protein from tilapia (Oreochromis mossambicus) as a function of storage in ice and frozen condition were evaluated. The results showed that actomyosin constituted about 57% of total soluble protein which decreased by4% after 12 days of storage in ice due to insolubilisation. During frozen storage, however, the actomyosin decreased by 5% after one month of storage at -20°C and by 12% in 4 months. The Ca2+ATPase activities decreased by 43% after 4 days of storage inice and by 69% after 2 months frozen storage. Mg2+ and EDTA ATPase activities were not significantly altered during ice storage but showed a decrease during frozen storage. Total sulfhydryl groups of actomyosin fraction were less (23 uM SH g"1 AM) initially and then increased. Turbidity of total soluble protein increased by two folds during ice and frozen storage. SDS-PAGE pattern of protein substantiates the insolubilisation of proteins during storage in ice and at -20°C.