Functional food products made from fish protein isolate recovered with isoelectric solubilization/precipitation

Isoelectric solubilization/precipitation (ISP) allows efficient recovery of fish protein isolate (FPI) that could be used in functional foods. There is an increasing interest in incorporating ω-3 polyunsaturated fatty acids (PUFAs) oils in food with a simultaneous sodium reduction. FPI was recovered from whole gutted trout using ISP. FPI was used as a main ingredient in heat-set gels made with ω-3 PUFAs oils (flaxseed, algae, fish, krill, and blend) and KCl-based salt substitute. The objectives were to determine (1) protein gelation, (2) color and texture, and (3) sodium and potassium content of the developed functional food (i.e., heat-set gels). Color properties were improved except when krill or algae oil was added. Texture profile analysis showed that ω-3 PUFAs generally did not affect texture of trout protein gels. The addition of ω-3 PUFAs oil improved heat-induced protein gelation as demonstrated by dynamic rheology. Elastic modulus increased when ω-3 PUFAs oil was added except krill oil. Salt substitute resulted in reduced sodium and increased potassium content in the heat-set gels. The functional food products developed from FRI were nutritionally enhanced with ω-3 PUFAs, had reduced sodium and increased potassium; while the color and texture properties were good and gelation properties were improved. © 2012 Elsevier Ltd.