Effect of protein aggregation on rheological properties of pea protein gels

Abstract

Yoghurt style gels are a promising way to increase the consumption of plant derived proteins. However, reaching texture properties similar to those commonly known from milk yoghurts while incorporating large amounts of plant-derived proteins, is a challenge that needs to be addressed to meet consumers expectations. Therefore, this study aims to investigate the influence of pH conditions (pH 6.0 to pH 8.0) during pre-treatment on the rheological properties of fermentation induced pea protein gels with a protein content of 10%. Results showed a strong correlation between the pH value during pre-treatment and the protein solubility after pH readjustment to pH 8. Solubility was highest if pea protein was pretreated at pH 8.0 and lowest if it was pre-treated at pH 6.0. Since only soluble aggregates are believed to participate in network formation, networks formed by pea protein pre-treated at pH 6 were coarser, than those formed by pea protein pre-treated at pH 8 owing to a lower degree of crosslinking caused by less available protein. Coarser networks and higher proportions of insoluble particles increased loss of water and lowered the storage modulus G' as well as the ability of the networks to recover after intense shearing. In particular pre-treatment at pH values below 7.0 led to gels with storage moduli of the same magnitude as those measured in commercial milk derived yoghurts. Adjusting the pH value during pretreatment of pea protein can therefore be considered a promising approach for the customisation of texture properties while maintaining a constantly high protein content.to protein-rich foods (Banovic et al., 2018), and yoghurt type products from plant derived proteins allow for the incorporation of up to at least 10% plant derived protein (Klost & Drusch, 2019;Klost, Giménez-Ribes, & Drusch, 2020).Plant-derived proteins (such as pea and soy) consist of hexameric 11S and trimeric 7S globular protein fractions. The general process of acid induced gelation has been extensively described by a variety of

Effect of Oxidation on Quality of Chiba Tofu Produced by Soy Isolate Protein When Subjected to Storage

“…It has been reported that the faster molecular mobility of solid particles was connected with the frequency-dependent property of G′ and G″ [ 39 ]. Both G′ and G′′ slightly increased as the increasing frequency of oscillating stress, which demonstrated that the characteristic of the Chiba tofu prepared in this study was close to a viscoelastic material [ 40 ]. The G′ and G′′ first increased and latterly slightly decreased with storage periods.…”

Applicable Plant Proteins and Dietary Fibers for Simulate Plant-Based Yogurts

“…PP exhibited an especially notable change in viscosity, increasing up to 497 cp in the 6.2-6.0 pH region. According to Klost et al (2020) [17], the solubility of PP is the lowest at pH 6.0, and Klost and Drusch (2019) [18] reported that the rate of coagulum formation begins to increase at pH 6.2-6.5 as the pH decreases due to the acid produced from LAB fermentation. A maximum rate is achieved at pH 6.0, and then gradually decreases until pH 5.5.…”

Aggregation and gelation of soy protein : Effects of selective proteolysis and physical modifications

“…Bi et al found the acid-induced hybrid gels of soy protein and locust bean gum/ĸ-Carrageenan displayed intercycle strain softening behavior in the NLVE regime [144,145]. This behavior was also found when the fermentation-induced pea protein gels were subjected to LAOS tests, but these gels displayed intracycle strain stiffening behavior when the amplitude was between 1.6% and 160%, and intracycle shear thinning behavior when the amplitude exceeded 160% [134,149]. LAOS tests have also been applied on gelatin gels [190,191], waxy rice starch gels [147], pectin-Ca gels [192],…”

“…In addition, while the σe of pure WPI gels was near zero for almost the entire cycle when γ0 reached 204%, one could still observe nonzero values for σe when the other gels were subjected to the maximum γ0 (1020%), a sign there was still residual elasticity in the material. That the gels containing SPI showed a slower transition towards plastic properties and still retained an elastic contribution to the response at higher strain, could be another indication of their coarser network structures, since coarser structures are less prone to a complete transition towards plastic behavior due to increased structural flexibility [149]. The higher flexibility could lead to a more gradual decrease in bond numbers, thus some elastic responses can still be detected at higher strain [149].…”

“…In spite of this, most studies on food biopolymer gels apply only SAOS tests to investigate their LVE behavior, and only a few studies have reported data in the NLVE regime. fermentation-induced pea protein gels [134,149], and various concentrated protein systems (Pea and soy protein and wheat gluten) [150] have been documented. The insights into non-linear rheology enabled these studies to provide a clearer and more detailed guide for designing novel plant protein gel-based foods like pea protein yoghurt and meat analogues.…”