Effect of Chilling and Freezing on Fish Muscle

Abstract

Muscle samples of Mystus seenghala were stored at two different low temperatures, i.e at 4±1 o C (chilled) and at-12±2 o C (frozen) for 21 days. Weekly analysis was conducted to measure protein, lipid, ash, moisture, free fatty acid, pH and total plate count. The result clearly reveals that during storage, both the samples showed a highly significant (p<0.01) decreasing trend in protein, lipid, ash and moisture content. After 21 days, the percentage decrease was 54.35% and 22.70% for protein and 82.64% and 56.68% for lipid, 10.96% and 4.89% for moisture and 38.92% and 37.88% for ash content in chilled and frozen sample respectively. However, the free fatty acid and pH showed highly significant (p<0.01) increasing trend in both the samples. Similarly, the bacteriological studies revealed that the total plate count (TPC) in chilled and frozen samples also showed an increasing trend. It was found within acceptable limits (TPC=6.04±0.11 log cfu/g) in chilled sample upto 10 th day and up to 14th day (TPC=5.78±0.2 log cfu/g) in frozen sample. Thereafter, the microbial quality further deteriorates and became inedible for human consumption. (