Structural, functional and sensorial properties of protein isolate produced from salmon, cod and herring by-product
Journal article, 2018
Nutritional, structural, functional and sensorial properties of protein isolate developed from salmon (Salmo salar), cod (Gadus morhua) and herring (Clupea harengus) by-product using the pH-shift method was studied. Function of the proteins in an emulsion system in terms of viscoelastic properties was also evaluated. Regardless of origin, the proteins showed satisfying nutritional value as reflected in their high essential amino acid content. The proteins contained significantly (p<0.05) higher proportion of active sulfhydryl groups and surface hydrophobicity compared to whey and egg white protein reflecting conformational changes caused by the pH-shift process. Solubility, emulsion and foaming capacity of the proteins showed a trend similar to soy protein and dependent on their origin. Cod protein had better emulsion and foaming capacity which was in line with its high surface hydrophobicity and myosin heavy chain content. Emulsions developed from cod and salmon proteins showed substantially better viscoelastic properties, with higher stability and viscosity compared to herring protein emulsions. Cod protein resulted low levels in sensorial attributes related to oxidation while herring protein showed high levels of fishy and rancid flavour and odour. Altogether, results showed that the proteins from fish filleting by-product have potential to be used as food ingredients, but their application would be governed by their origin and sensorial properties.