Physicochemical properties of acid‐soluble collagens from different tissues of large yellow croaker (Larimichthys crocea)

Summary Acid‐soluble collagens (ASCs) were extracted and characterised from different tissues of large yellow croaker ( Larimichthys crocea ). The yields of ASCs in bones, skins, scales and muscles were 3.22 ± 0.47%, 42.30 ± 1.15%, 2.82 ± 0.31% and 0.89 ± 0.12%, respectively. SDS‐PAGE and ATR‐FTIR analysis showed that all ASCs were type I collagen with intact triple helical structure and consisted of α1,3‐chain, α2‐chain, β‐chain and γ‐chain. Quantitative analysis of SDS‐PAGE revealed that the ratio of β‐chains in ASC from scales was lower than other tissues. The imino acid contents of ASC from bones, skins, scales and muscles were 169, 167, 162 and 173 residues/1000 residues, respectively. The maximum transition temperature ( T m ) of ASC from scales was 30.15 °C, lower than the other three ASCs, indicated that the thermal stability of collagen was affected by both the content of imino acid and β‐chains. The results also implied that thermal stability of ASC might exist the tissue specificity among different fish species.