Seasonal variations in the channel catfish (Ictalurus punctatus): Nutritional composition, texture, and physicochemical properties of myofibrillar protein

Channel catfish is an important freshwater culture fish and occupies a large proportion in the field of freshwater aquatic product processing. In this study, changes in basic nutritional composition, texture characteristics and myofibrillar protein (MP) characteristics of the channel catfish (Ictalurus punctatus) were determined with respect to the seasons. Chromatography, TA-XTPlus physical property analyzer and Fourier transform infrared spectroscopy were used to analyze the samples for amino acid profile, fatty acid profile, textural properties and MP structure, respectively. The maximum moisture content of muscle was obtained in winter, and the fat content was highest in summer and lowest in winter. The highest levels of saturated fatty acids (SFA), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), resilience and cohesion were found in summer. The hardness was 40% higher in winter than that in summer. The study of MP properties in different seasons revealed that MP had higher surface hydrophobicity but lower α-helix content in autumn and winter (17.40% and 17.52%, respectively). There was no significant difference in the total sulfhydryl content between seasons (P > 0.05), with the highest MP endogenous fluorescence intensity in spring. Seasonal variations in the nutritional quality and MP characteristics may be related to different water temperature environments, the duration of the overwintering period, and the different expression of genes. This study bridges the gap in the quality evaluation system of channel catfish and provides some useful information for its deep processing.