Biochemical, sensory and microbiological attributes of bream (Megalobrama amblycephala) during partial freezing and chilled storage

Abstract

Bream is one of the main farmed freshwater fish species in China. This study aimed to examine the nucleotide degradation of bream during partial freezing and chilled storage and to assess the possible usefulness of nucleotide ratios (K, Ki, H, P, Fr and G values) as freshness indices in comparison with sensory assessment and total viable counts. Total viable counts were 5.74 and 4.66 log(colony-forming units g(-1)) on the day of sensory rejection under chilled storage and partial freezing storage respectively. The inosine 5-monophosphate decrease and inosine increase were faster in chilled storage than in partial freezing storage. Hypoxanthine levels increased continuously with time under both storage regimes. Among the nucleotide ratios, the K, Ki, P, G and Fr values were superior to the H value and provided useful freshness indicators for both storage conditions. Bream in chilled storage were sensorially acceptable only up to 10 days, compared with 33 days for bream in partial freezing storage. Partial freezing delayed the nucleotide degradation of bream.