Edible coatings of chitosan and fucoidan with crucian carp protein hydrolysate to extend shelf life of beluga sturgeon fillets

This study investigates the problem of preserving the quality and shelf life of beluga sturgeon (<i>Huso huso</i>) fillets under refrigeration. The aim of the research is to evaluate the effectiveness of composite edible coatings made from chitosan and fucoidan, in combination with crucian carp (<i>Carassius carassius</i>) protein hydrolysate (CPH). Significant methodology includes the preparation of hydrolyzed proteins using the enzyme Alcalase for 90 min, followed by encapsulation within nanoliposomes. Fucoidan was extracted from the brown alga <i>Sargassum latifolium</i>, and its antioxidant and antimicrobial properties were assessed. Six types of edible coatings were developed, including chitosan and chitosan-fucoidan with CPH and nano CPH (NCPH) at concentrations of 0 %, 0.5 %, and 1 %. The chemical, microbiological, and sensory characteristics of the coated and uncoated fish fillets were evaluated over a 16-day storage period. Results indicated a particle size of 102.98 nm, a zeta potential of 12.29 mV, and an encapsulation efficiency of 75.84 %. The extraction yield of fucoidan was 5.89 %, with total carbohydrate content of 59.2 %, protein content of 9.21 %, sulfate content of 21.78 %, and uronic acid content of 8.85 %. Fucoidan exhibited significant antioxidant and antimicrobial activity. The analysis of chemical and microbiological factors in the fish fillets revealed significantly lower values in the coated fillets compared to the control (P < 0.05). The use of CPH significantly reduced the rate of oxidative spoilage, and increasing CPH concentration resulted in a slower rise in microbial load (P < 0.05). The best outcomes were observed in NCPH. Ultimately, the combination of chitosan-fucoidan and 1 % NCPH maintained acceptable conditions for most microbiological, chemical, and sensory indices by the end of the storage period. These findings suggest that these edible coatings could serve as an effective method for enhancing the quality and shelf life of fish fillets in the food industry.