Evaluation of edible coating based on chicken foot gelatin/green walnut skin extract on physical characteristics, color, and texture properties of rainbow trout fillet during storage in the refrigerator

Considering the high perishability, quality reduction, and nutritional value of the fish during the storage period, the aim study is to investigate the edible coating based on chicken feet gelatin/green walnut skin extract to preserve the physical characteristics, color, and texture properties of Oncorhynchus mykiss fillet during storage in the refrigerator. After extracting gelatin and green walnut skin extract, the coating solution were prepared. The fillets were coated by immersion method. Physical characteristics (moisture), color indices (L*, a*, and b*) as well as textural properties (hardness, springiness, and Cohesiveness) of the fillets were evaluated during 12 days of storage (on days 0, 4, 8, and 12). Variance analysis was performed by Minitab software (version 18). The mean data comparison by Tukey's test is at a 95% confidence level. The results showed significant moisture retention of coated fillets (p<0.05). The L* and a* index of fillets decreased during 12 days of storage. While, the b* index was increased in all samples (p<0.05). The evaluation of the texture of the fillets showed a decrease in hardness and Cohesiveness, but springiness was increased (p<0.05). The coat had significantly higher hardness, Cohesiveness, and lower springiness than the control sample (p<0.05). Increasing the concentration of green walnut skin extract from 500 to 1000 ppm increased the quality of fillets (p<0.05). In general, It can be concluded that edible coating based on chicken leg gelatin/green walnut skin extract effective to increase shelf- life aquaculture industry.