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ARS Home » Southeast Area » Stoneville, Mississippi » Warmwater Aquaculture Research Unit » Research » Publications at this Location » Publication #386559
Research Project: Mississippi Center for Food Safety and Post-Harvest Technology

Location: Warmwater Aquaculture Research Unit

Title: Protein extraction pH and cross-linking affect physicochemical and textural properties of protein gels made from channel catfish by-products

Author
item TAN, YUQING - Mississippi State University
item CHANG, SAM - Mississippi State University

Submitted to: Journal of the Science of Food and Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/25/2021
Publication Date: 1/27/2021
Citation: Tan, Y., Chang, S. 2021. Protein extraction pH and cross-linking affect physicochemical and textural properties of protein gels made from channel catfish by-products. Journal of the Science of Food and Agriculture. https://doi.org/10.1002/jsfa.11126.
DOI: https://doi.org/10.1002/jsfa.11126

Interpretive Summary: Catfish aquaculture in the US Southeastern states is the most important aquaculture in the United States. However, huge amount of by-products were produced in catfish fillet production each year. This manuscript studied the possibility of gel making (surimi-like products) by using proteins extracted from catfish by-products, and investigate the effect of different protein extraction conditions and protein modifications on the gel properties. This study is an original contribution that has not been reported in the literature, and is important for the utilization of the catfish by-products for making functional food ingredients. We believe the manuscript provides the scientific basis for the value-added utilization of catfish by-products in the future.

Technical Abstract: Channel catfish farming is very important aquaculture industry in the Southern states of the USA. However, huge amounts of by-products are generated from catfish fillet-processing. The by-products (mostly heads and bone frames) are excellent sources of proteins. Currently, catfish by-product has little value, and is regarded as a ‘waste’, which if not utilized properly could cause serious environmental pollution. Therefore, to find a way to utilize those by-products is critical for enhancing the economy of aquaculture. Protein isolates were extracted from the mixture of catfish by-products (heads and frames) under different alkaline conditions (pH 7.5–11) and made into protein gels. Secondary structures of extracted protein isolates were studied. Microbial transglutaminase (MTGase, 0–4U per gram of proteins) was incorporated to improve gel structure. Gelling, physicochemical, textural and thermal properties of protein gels treated with/without MTGase were investigated. Protein pattern changes of MTGase treated protein gels were studied and the microstructure of the protein gels was analyzed. Results showed alpha-helicity of protein isolates made at pH 11 was 21.5% lower than that extracted at pH 8.5. Storage modulus (G0) of protein gel decreased with increasing extraction pH (pH > 9) of the corresponding protein isolate. MTGase treatment exhibited significant effects on denaturation temperature and enthalpy of protein gels. Excessive MTGase (>2U per gram) could weaken the gel structure. It can be concluded that catfish protein isolates can be extracted from catfish by-products and made into protein gels, which are value-added products.