Influence of Natural Antioxidants on Biochemical Stability of Labeo rohita and Catla catla During Frozen Preservation

The present study was conducted to evaluate the influence of frozen storage and natural antioxidant treatments on the biochemical stability of the freshwater fishes Labeo rohita and Catla catla. Both species are nutritionally important and widely consumed, but their high moisture content, active endogenous enzymes, susceptibility to microbial contamination, and abundance of unsaturated lipids make them highly perishable. Fish samples were treated with NaCl + Ascorbic Acid and NaCl + Lemon Peel Powder and maintained under refrigerated (0±2°C) and frozen (-20±2°C) conditions for 21 days. Biochemical characteristics were assessed at 0, 7, 14, and 21 days using moisture content, acid value, and centrifugal tissue fluid (CTF) as indicators of changes in water retention, lipid deterioration, and tissue integrity. The observations showed an overall decline in moisture content and CTF values during storage, whereas acid value increased with storage duration, indicating progressive biochemical deterioration. The samples stored at -20±2°C generally exhibited better preservation than those stored at 0±2°C, demonstrating the advantage of lower storage temperature in slowing biochemical changes. Among the treatments evaluated, the combination of NaCl and ascorbic acid showed superior preservation efficiency and was associated with reduced oxidative deterioration. NaCl combined with lemon peel powder also showed preservative potential, which may be related to the natural phenolic constituents of citrus peel. The study therefore indicates that appropriate low-temperature storage, particularly at -20±2°C, together with natural antioxidant treatment can contribute to maintaining biochemical quality and extending the storage stability of Labeo rohita and Catla catla.