Recently, the research team of Qiang Wang, an innovation team for plant protein structure and function regulation, reviewed the trends in high-moisture extrusion technology with regarding to protein sources, theoretical basis for the process, equipment, and evaluation methods for product quality. The relevant research results were published in the journal Trends in Food Science & Technology (IF=16.002) with the title “High-moisture extruded protein fiber formation toward plant-based meat substitutes applications: Science, technology, and prospect”.

Background: Recently, plant-based meat substitutes have generated considerable interest for their benefits in terms of environmental sustainability and personal health. High-moisture (above 40%) extrusion is an important technology for preparing whole-cut plant-based meat substitutes with meat-like fibrous structure and texture. However, it remains challenging on a more fundamental level to understand the interactions during extrusion processing related to the transition of the protein molecules or phase into fibrous structures, which is considered as a “black box” with scarce information inside.

Scope and approach: Here, protein sources that can be texturized by high-moisture extrusion are summarized. Next, high-moisture extruded protein texturization theories are explained from three interdisciplinary subjects. Furthermore, technical points including extrusion conditions, screw configuration, and cooling die design are analyzed. Lastly, a comprehensive evaluation of high-moisture extruded plant-based meat substitutes is outlined.

Key findings and conclusions: A wide range of protein sources from legumes, oilseeds, cereals, miscellaneous beans, vegetables, algae, fungus, and insects are available for high-moisture extrusion. There is increasing consensus that the dynamics of protein aggregation and phase separation determine the formation of fibrous structures during high-moisture extrusion. Protein fibrous structure formation mainly occurs from the die to the cooling zone through a “sub-layer transformation” cross-linking. A combination of simulation work with actual experiment requires additional focus and insight for the regulation and control of high-moisture extrusion processes. Comprehensive evaluation methods are necessary to compare plant-based meat substitutes with different animal meats.

Graphical abstract

Associate Professor Jinchuang Zhang and PhD student Qiongling Chen were the co-first authors, Professor Qiang Wang and David L. Kaplan as co-corresponding authors. This work was supported by the National Key Research and Development Plan of China (2021YFC2101402), the National Natural Science Foundation of China (31901608), and the Science and Technology Innovation Project of Chinese Academy of Agricultural Sciences (CAAS-ASTIP-2022-IFST).

Link to the paper: https://doi.org/10.1016/j.tifs.2022.08.008