Characteristics comparison of collagens from squid skin by different extraction methods

Abstract

To provide a scientific basis for the comprehensive utilization of squid processing by-products, squid skin collagen was extracted by acid, enzyme and hot water, respectively, and the physicochemical characteristics of the collagens were compared. The results showed that the yield of acid soluble collagen (ASC), pepsin soluble collagen (PSC) and heat soluble collagen (HSC) was 7.41 ± 0.55%, 32.86 ± 0.67% and 42.23 ± 0.82% (dry weight basis), respectively. FTIR, UV and SDS-PAGE analysis suggested that ASC, PSC and HSC had the typical characteristics of type I collagen and retained the complete triple helix structure. The thermal stability of ASC was higher than that of PSC and HSC. ASC had a more uniform and compact porous network structure than PSC, while HSC was an irregular sheet structure. The solubility of HSC was obviously higher than that of ASC and PSC, and the effect of pH and NaCl on the solubility of HSC was inconspicuous in the experiment conditions. The extraction methods had significant effects on the structure and physicochemical properties of collagens. The solubility of HSC suggested that it was more suitable for liquid products. Moreover, the structural characteristics and high thermal stability of ASC made it suitable for biomedical materials and thermal processing products.