Chitooligosaccharide–gallic acid complexes suppress the denaturation of myofibrillar proteins in peeled shrimp (Litopenaeus vannamei) during frozen storage

Summary The cryoprotective effects of chitooligosaccharide–gallic acid (COS–GA) complexes on peeled Pacific white shrimp were investigated and compared with single treatments of COS, GA and polyphosphate (PP) during 49 days of frozen storage at −5 °C. The data revealed a significant improvement in the antioxidant activity of COS through the conjugation of COS and GA. The soaking treatments of COS–GA and PP effectively maintained the water‐holding capacity and sensory properties of shrimp muscle compared with the water‐soaked shrimp (control). Furthermore, the COS–GA‐soaked shrimp samples exhibited significant inhibitory effects on the textural and chrominance deterioration of muscle tissues compared with the control samples. Chemical analyses demonstrated that the COS–GA treatment also preserved higher levels of myofibrillar protein content, total sulfhydryl content and Ca 2+ ‐ATPase activity in the frozen shrimp samples. Histological observations indicated that the COS–GA soaking treatment effectively protected the integrity and stability of muscle tissues. Overall, COS–GA exhibited superior antioxidation and water‐retaining properties, stabilising the shrimp muscle during long‐term frozen storage.