Properties and characteristics of salmon frame protein isolate films influenced by glycerol and squalene

Abstract

Characteristics of edible/biodegradable film based on salmon frame protein isolate (SFPI), a processing by-product, containing glycerol at two different concentrations (50 and 65% by weight of protein) with and without 30% squalene (by weight of protein) were investigated. Without squalene, the SFPI film generally had higher hydrophilicity when higher concentration of glycerol was used as indicated by higher (p < 0.05) water-vapour permeability (WVP). The addition of squalene augmented yellowness and hydrophobicity of SFPI film as indicated by higher b* colour coordinate and lower WVP (p < 0.05), respectively, in comparison to those without squalene. The squalene also promoted the interactions in SFPI film matrix as revealed by Fourier-transform infrared spectra. These interactions were related to a superior mechanical properties, high barrier properties, and increased thermal resistance of the resulting SFPI film. Therefore, the addition of 30% squalene along with 50% glycerol as plasticiser improved physicochemical, mechanical, barrier, and thermal properties of SFPI film, which could be used as an alternative film for edible/biodegradable food packaging.