EFFECTS OF CHITOSAN COATINGS INCORPORATED WITH GARLIC OIL ON QUALITY CHARACTERISTICS OF SHRIMP

The effect of chitosan-based edible coatings (CC) incorporated with garlic (Allium sativum) oil at 0.5, 1.0 and 1.5% on shrimp (Parapenaeus longirostris) meat quality was investigated during refrigerated storage (4C) for 11 days. CC application resulted in lower pH (P < 0.05) as compared with the uncoated control. Reductions in aerobic plate counts (APC) up to 2 log units were promoted by CC. Combined effect of garlic oil (GO) and CC was observed. CC resulted in lower APC with GO (P < 0.05) toward the end of storage. CC reduced total volatile base nitrogen and trimethylamine nitrogen contents in comparison with C (P < 0.05), with no significant effect of GO incorporation (P > 0.05). Antioxidant activity of CC was only apparent during the earlier periods of storage, while GO accelerated lipid oxidation as measured by thiobarbituric acid value. CC application with or without GO generally resulted in higher lightness (L-star), and lower redness (a(star)) and yellowness (b(star)) values. Minimum concentration of GO incorporation (0.5%) into chitosan coating could be useful in extending the shelf life of shrimp meat during refrigerated storage.