FRACTIONATION OF MUSCLE PROTEINS OF FRESH WATER FISH AND CHANGES DURING ICED STORAGE

SUMMARY: Fractionation of muscle proteins of four varieties of fresh water fish after storage in ice was carried out by serial dilution of a buffer extract of ionic strength 0.55. Precipitation of actomyosin was complete at an ionic strength of 0.175 and fibrillar fraction at 0.05. In Ophiceohalus sp. the initial solubility of proteins was 91‐93%. The solubility fell to 82% by the 5th day and increased on further storage up to 13 days. Further storage indicated a fall in solubility. The fall in solubility on the 5th day coincided with the highest level of actomyosin and maximum rigor rigidity of the round fish. Actin solubility in buffer showed the same pattern as solubility of total proteins. The quantity of actin not reconvertible into f‐actin showed an increase during storage. Viscosity of buffer extracts showed an increase during development of rigor and decrease on further storage as reflected by level of preformed actomyosin. Copyright © 1969, Wiley Blackwell. All rights reserved