229: Modulating Rheological and Microstructural Properties of Hybrid Meat Protein Gels Using Structurally-Modified Pea Protein

Introduction

Hybrid meat analogues with 20–50% of animal protein replaced by plant protein offer a viable alternative for consumers transitioning from an all-meat to plant-fortified diet. Although native plant protein can partially reinstate product texture at low-salt conditions where muscle myofibrillar protein is minimally soluble, its efficacy is constrained by the inherently lower gelation capacity. High-intensity ultrasound was previously shown to modify plant protein structure for functionality enhancements. This study tested the hypothesis that ultrasound-modified pea protein (UPP) could promote thermal gelation of binary muscle/pea proteins, aiming to develop reduced-salt hybrid meat analogues.

Methods

Pea protein isolate was structurally modified using high-intensity ultrasound to obtain UPP. Total hybrid proteins were collected by filtration of pork muscle/UPP blends at ratios of 100:0, 75:25, and 50:50 (w/w) under two salt levels (0.3 and 0.6 M NaCl). Soluble hybrid proteins (SHP, 8,000 x g) were characterized for polypeptide distribution (SDS–PAGE), integrated structural attributes (circular dichroism, intrinsic fluorescence, and surface hydrophobicity), particle size, and zeta potential (dynamic light scattering). Gelling potential of total hybrid protein was assessed using dynamic rheological measurements; hardness, microstructure, participating proteins, and water distribution within the gels were also analyzed.

Results

UPP substitution, yielding a higher SHP content, reduced the hybrid system's α-helix content but increased the surface hydrophobicity by 47–97%, resulting in stronger hydrophobic interaction of hybrid proteins. Under reduced-salt conditions (0.3 M NaCl), hybrid proteins displayed a faster thermal aggregation rate than those under regular salt conditions (0.6 M NaCl). Although hybrid gels were softer than all-muscle gels at 0.3 M NaCl (p < 0.05), the hardness (0.3 N) at a 50:50 substitution ratio was comparable to that under regular-salt concentrations. Electron microscopy revealed a dense, uniform protein network in reduced-salt hybrid gels. SDS–PAGE confirmed the active involvement of pea 7S/11S globulins in gel formation. Immobilized water in reduced-salt gels, as evidenced by 1H-NMR, was tightly bound, contributing to comparable water-holding capacity to gels under regular-salt concentrations.

Significance

This study highlights the feasibility of ultrasound-functionalized pea protein to improve gelation in hybrid meat analogues, offering a promising strategy for developing sodium-reduction meat alternatives.

Authors: Xi Sun, Weiqi Zhou, Jiayi Mo, Qingling Wang