Unravelling the impact of ohmic heating on commercial pea protein structure

Abstract

Pea protein (PP) has attracted the attention of the food industry and the scientific community as a substitute for more established plant proteins such as soy proteins. However, commercial PP often displays poor solubility which limits its functionality and further use by the food industry. To overcome this challenging issue, plant protein modification techniques for improved functionality have been investigated. Ohmic heating (OH) is an emergent thermo-electrical processing technology which has demonstrated potential in modifying protein structure and therefore its functionality. In this work, the potential use of OH has a physical technique for protein modification was investigated. Therefore, a commercial PP was submitted to OH application, at treatment temperatures ranging from 90 to 150 °C and the potential changes in PP solubility upon OH application were evaluated. An increase in protein solubility of ca. 240 % was observed after OH application at 150 °C. Protein structural characterization was performed, suggesting PP structural rearrangement, rather than unfolding, upon OH application. Furthermore, OH application presumably promoted the dissociation of the insoluble aggregates already present in the commercial PP sample. Moreover, higher treatment temperatures (particularly from 110 °C onwards) may have induced protein hydrolytic cleavage of the peptide bond to some extent, leading to the formation of mainly small soluble aggregates and peptide fragments. These results open novel perspectives for the use of OH as a promising tool for improving commercial PP solubility and, therefore, enabling its tailored application in the food industry.