Protein network density and fibrous structure control of soy protein isolate-based high-moisture meat analogs using yeast or rice protein isolates with distinct glass transition temperatures

Abstract

This study investigates the impact of yeast protein isolate (YPI) and rice protein isolate (RPI) on the structural and functional properties of soy protein isolate (SPI)-based high-moisture meat analogs (HMMA). By leveraging the distinct glass transition temperatures (T_g) of YPI and RPI, this study examines their roles in modulating SPI network density and fibrous structure formation during high-moisture extrusion (HME). It was revealed that YPI and RPI altered the rheological and microstructural properties of SPI-based gels, leading to differences in hardness, cohesiveness, and texturization index. YPI, with its higher T_g, maintained particulate form during processing, acting as a physical filler that improved structural anisotropy and enhanced fiber formation. RPI, although more susceptible to thermal denaturation, contributed to a flexible protein network, enhancing textural properties at moderate concentrations. Chemical interaction analysis revealed that while YPI and RPI reduced hydrogen and hydrophobic interactions, they increased disulfide bond formation at optimal levels, promoting a stronger fibrous structure. However, excessive incorporation led to protein aggregation and reduced network stability. Such findings suggest that the strategic incorporation of YPI and RPI enables precise tuning of the SPI-based HMMA texture, providing a novel approach to optimizing plant-based meat structures through targeted protein selection and extrusion processing. These findings not only advance the understanding of protein-protein interactions during extrusion but also provide practical strategies for improving the texture and fibrous structure of plant-based meat products, facilitating their commercial application.