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ARS Home » Southeast Area » Stoneville, Mississippi » Warmwater Aquaculture Research Unit » Research » Publications at this Location » Publication #353963

Research Project: Umbrella Project for Food Safety

Location: Warmwater Aquaculture Research Unit

Title: Isolation and characterization of collagen extracted from channel catfish (Ictalurus punctatus) skin

Author
item TAN, Y. - Mississippi State University
item CHANG, SAM - Mississippi State University

Submitted to: Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/4/2017
Publication Date: 1/1/2018
Citation: Tan, Y.Q., Chang, S. 2018. Isolation and characterization of collagen extracted from channel catfish (Ictalurus punctatus) skin. Food Chemistry. 242(3):147-155.

Interpretive Summary: Channel catfish farming is the most important warm water aquaculture in the Southeastern United States. The by-products, including heads, skin, bone frame and viscera, account for 55-65% of the whole fish mass after fillet processing. The by-products contain about 15% of skin on a dry basis. The skin contains mostly collagen and may be extracted for use as functional food ingredient. Currently, the by-products have little value and are regarded as waste, which if not utilized properly would produce environmental pollution. The catfish skin was ground and extracted by different processes. The chemical and engineering parameters for optimal extraction were developed. The results showed that skin can be best extracted using acid extraction with homogenization . This study serves as the foundation for further large-scale commercial extraction of skin collagen for foods and cosmetic use.

Technical Abstract: Channel catfish skin is a by-product from catfish fillet production and contains 80% of proteins after drying. Collagens were extracted from catfish skins by: (1) acid extraction; (2) homogenization-aided; and (3) pepsin-aided extraction methods. Kinetic analysis of extraction was performed. Sodium dodecyl polyacrylamide get electrophoresis (SDA-PAGE) was carried out for all collagens extracted under different conditions. Protein solubility, zeta potential, circular dichroism and gel strength methods were used to characterize the collagen extracted by three methods to determine optimal conditions. Protein recovery rate from minced skins extracted with pH 2.4 HCl containing 23.6 KU/g pepsin was the highest (64.19%). SDS-PAGE showed that collagens extracted with different methods had different proteins ratio patterns, even though the molecular mass of collagen subunits were similar, 123 and 113 KDa for a1 and a2 chains, 226 KDa for ß chain and 338.5 KDa for ' chain, respectively. Channel catfish skin collagens were typical type I collagens and could have applications in food, medical and cosmetic industries. The acid and homogenization aided extraction methods produced collagen with higher gel strength than that produced by pepsin hydrolysis.