Characterization and Profiling of Protein Hydrolysates from White and Red Meat of Tuna (Euthynnus affinis)

Abstract

Tuna is considered as one of the richest source of fish protein and concentrating these proteins in the form of hydrolysate finds application in a wide range of food ingredients and pharmaceutical products. Protein rich red meat from tuna has limited use compared to white meat and is usually processed into products with low market-value realisation. An effective alternative is the conversion of this red meat into high value protein hydrolysates. With a view to this aspect, in the present study a comparative assessment of hydrolysates derived from white and red meat of tuna (Euthynnus affinis) was carried out. Protein hydrolysate was prepared using 1% (w/w) papain with the hydrolysis time of 60 min under optimal hydrolytic conditions to obtain tuna white meat protein hydrolysate (TWPH) and tuna red meat protein hydrolysate (TRPH). The protein content in tuna red meat and white meat were 28.34 ± 1.63 and 26.34 ± 0.79%, respectively whereas protein recovery in their respective hydrolysates were about 36.87 and 42.14%. Evaluation of the functional properties of protein hydrolysates viz., solubility, oil absorption capacity (OAC), foaming properties and emulsifying properties revealed that except OAC and Emulsifying Activity Index, all properties were comparatively higher for TWPH. However antioxidant studies viz., DPPH radical scavenging activity, reducing power and metal chelating activity revealed higher potential for TRPH compared to TWPH. Further detailed studies are required with respect to the variations in these properties as intrinsic as well as extrinsic factors can have a major influence on the characteristics of the derived hydrolysates.