Role of interfacial elasticity (E′) as an indicator for the foam characteristics of plant proteins

Abstract

This paper addresses the interfacial dilatational properties and foaming behavior of three plant protein isolates obtained from rapeseed, sunflower, and linseed meals, at concentrations ranging from 1 to 60 g/L. The goal of this study was to highlight the link and the correlations between the interfacial storage elasticity modulus (E′) and foaming properties through both experimental values and statistical methods. The nature and the concentration of proteins have a strong impact on the interfacial and foam properties. Rapeseed albumin isolate exhibits improved properties with increasing protein concentration, displaying higher interfacial dilatational elasticity and leading to the higher foamability, foam elastic modulus G′_Foam, and moderate foam stability. In contrast, linseed and sunflower protein isolates behave differently. Both show an enhancement in interfacial elasticity and foam properties up to a critical concentration, which indicates the presence of protein aggregates. This induces an antifoaming effect rather than foam stabilization, leading to a simultaneous decrease in the elastic interfacial modulus and inhibition of the foam characteristics. A clear correlation between E′ and several foam properties, including foamability, foam elastic modulus, half-life stability t1/2, and the foam stability after 1 h, was highlighted. The relationships are statistically significant with p-values substantially lower than 0.05. Positive correlations are confirmed between E′ and all the foam properties, indicating that the enhancement of E′ induces better foam properties.