ATPASE ACTIVITY, SURFACE HYDROPHOBICITY, SULFHYDRYL CONTENT AND PROTEIN DEGRADATION IN REFRIGERATED SEABASS MUSCLE IN MODIFIED ATMOSPHERE PACKAGING

Abstract

The effect of modified atmosphere packaging (80% CO2, 10% O2, 10% N2) on ATPase activity, surface hydrophobicity, sulfhydryl content and degradation of proteins in seabass muscle during storage at 4C was investigated. No changes in Ca2+-, Mg2+-, Mg2+-Ca2+-ATPase activities of natural actomyosin (NAM) in seabass slices kept under MAP were observed throughout the storage for up to 21 days (P > 0.05). However, a slightly increased Mg2+-EGTA-ATPase was found. For seabass slices stored under air atmosphere, Ca2+-ATPase activity decreased, whereas Mg2+-EGTA-ATPase activity increased (P < 0.05) with a concomitant loss in Ca2+-sensitivity. Lower decreases in total sulfhydryl content but higher increases in surface hydrophobicity were observed in samples stored under MAP, compared to those kept under air atmosphere. No marked autolytic degradation in samples kept under MAP was observed throughout the storage as monitored by no changes in myosin heavy chain, free α-amino acid and trichloroacetic acid soluble peptide. Conversely, a considerable degradation was found in samples kept under air atmosphere, especially after 9 days of storage. Therefore, MAP is a promising means to retard the changes in muscle proteins, especially degradation.