Valorization of Pink Salmon (Oncorhynchus gorbuscha) Processing By-Products: Nutritional Composition, Starch-Modified Gel Quality and Digestibility.

Pink salmon (Oncorhynchus gorbuscha) processing by-products represent an underutilized resource with considerable potential for value-added applications. To evaluate the nutritional profile and investigate the effects of different starches (native and modified) on the gel properties of the pink salmon by-products, the proximate composition, amino acid profile, and fatty acid profiles of the by-products were analysed, followed by assessments of the gel texture, water-holding capacity, cooking loss, color, microstructure, and in vitro digestibility. The results demonstrated that the by-product meat possessed a high protein content and was rich in polyunsaturated fatty acids (PUFAs), with an essential amino acid-to-total amino acid (EAA/TAA) ratio of 45.82% and an n-3/n-6 ratio of 1.34, indicating favourable nutritional quality for human consumption. Although the by-product meat alone formed a relatively soft gel, the incorporation of starch markedly improved its gel properties. Among the evaluated starches, tapioca hydroxypropyl distarch phosphate (HDP) produced the greatest improvements in texture profiles and water-holding capacity while reducing cooking loss and promoting the formation of a denser and more uniform gel microstructure. Furthermore, HDP significantly enhanced the dry matter digestibility of the starch-modified gels prepared from pink salmon by-product meat. These findings demonstrate that pink salmon by-product meat can serve as a promising material for producing nutritional functional food and that HDP is an effective additive for improving both gel quality and digestibility, thereby supporting the sustainable valorization of fishery processing byproducts.