Utilization of protein isolates from rohu (Labeo rohita) processing waste through incorporation into fish sausages; quality evaluation of the resultant paste and end product

BACKGROUND Fish processing waste could be valorized by recuperating the nutrients for human consumption. Employing a suitable process would address the pollution problems associated with its dumping and would contribute to food security. In this study, protein isolates obtained from rohu (Labeo rohita) processing waste through the pH shift process (pH 13.0) were valorized through incorporation into pangasius (Pangasius pangasius) mince sausages (0.0, 50, 100, 250, and 500 g kg(-1)). These sausages were analyzed for their proximate composition, and their physical and eating quality. RESULTS Increasing the isolate content (11.57% to 16.14%) in sausages increased their protein content and whiteness values (P < 0.05). At 250 g kg(-1) level, the cooking yield was maximum, and the expressible fluid content of paste was minimum. Moreover, adding rohu protein isolates in pangasius mince increased the expressible moisture and decreased its folding and gel strength values (P < 0.05). The gel strength values were highest for the sausages without isolates (2648.67 g cm). In contrast, in the sausages containing 250, 100, and 500 g kg(-1) isolate, the values were determined to be 847.88, 731.21, and 611.06 g cm, respectively. Replacing pangasius mince with rohu protein isolates had a non-significant effect on the sensory attributes of the sausages. CONCLUSION Replacing pangasius mince with rohu protein isolates at 250 g kg(-1) resulted in superior quality sausages compared with other levels tested. Incorporating rohu protein isolates in fish sausages improved the nutritional value without significantly reducing their eating quality. The findings of this study indicate promising potential for developing nutrient-rich foods using fish protein isolates. (c) 2021 Society of Chemical Industry.