Evaluation of protein isolate obtained from byproducts of hybrid sorubim (Pseudoplatystoma reticulatum x Pseudoplatystoma corruscans)

Industrial fish processing generates large quantities of protein-rich byproducts, which are usually discarded because of their low commercial value. It is therefore very important to find feasible alternatives to make use of this protein-rich raw material. The aim of this study was to obtain protein isolate from the byproducts of the fish hybrid sorubim ( Pseudoplatystoma reticulatum x Pseudoplatystoma corruscans ). After obtaining the fish protein isolate (FPI) from hybrid sorubim, the proximate composition of the raw material and of the isolate were determined and the functionality of the FPI was also evaluated. The mechanically separated meat (MSM) of hybrid sorubim contained 73.98% moisture, 37% lipids (dry basis-d.b.), 56.85% protein (d.b.) and 6.13% ash (d.b.). The protein isolate contained 5.61% moisture, 95.21% protein (d.b.), 3.06% lipids (d.b.) and 1.71% ash (d.b.). As for functionality, the isolate showed high solubility (88.5%), good water holding capacity (20.11 mL) and low oil holding capacity (2.03 mL). The process was considered efficient, in view of the high protein concentration and low moisture and lipids levels obtained in the isolate. The high water holding capacity and solubility confirm the promising potential of fish protein isolate from hybrid sorubim for use in the production of high added-value products.