Postmortem Changes of Cage-Farmed Grouper (Epinephelus coioides) Stored in Ice

Abstract

Freshly harvested grouper from sea cage was stored in ice, and its quality changes including biochemical [total volatile base nitrogen (TVB - N), trimethylamine nitrogen (TMAN), water - soluble nitrogen (WSN) and salt - soluble nitrogen (SSN), peroxide value (PV) and thiobarbituric acid reactive substance (TBARS)], physical (color, texture and pictorial changes), sensory and microbiological [aerobic plate count (APC)] changes were evaluated during storage. TVB - N increased from 8.02 to 29.79 mg% at the end of the 24th day in ice. WSN and SSN decreased from 9.8 and 14 mg% on the 0th day to 2.86 and 5.25 mg%, respectively, at the 24th day. TBARS showed a fluctuating trend; however, the value has increased from 0.021 to 0.592 mg MDA/kg sample, respectively. The color analysis indicated an obvious change in the lightness of meat. On 0 day, the L* value was 48.74, which was increased to 56.89 at the end of storage. A reduction in hardness values was noticed with the extent of iced storage. Color and appearance of eyes, gills and pectoral fins served as major pictorial tools to determine the freshness of grouper. APC increased to 7.16 log 10 cfu/g on the 24th day of storage. Based on sensory evaluation (raw and cooked) and microbiological quality, the shelf life of grouper was determined as 22 days during iced storage.