High moisture extrusion technology assisted by enzymatic protein-protein crosslinking approach to improve the texture of plant-based meat analalogues

Currently plant-based meat industry heavily relies on using additives, including, flavourings, colouring, oil and binding & texturizing agents The binding & texturizing additives such as methylcellulose, gums (e.g. carrageenan, guar, gellan, xanthan, alginate) and fibres (e.g. pea, oat, bamboo) are to create the meat-like texture for cold & hot consumption. There is a growing desire from consumers to have clean label and heathier plant-based food. A significant number of studies already shown that additives, such as methyl cellulose (MC) is not digestible, doesn't have a nutritional benefit, & may have an adverse heath effect after prolonged ingestion
Modifying the plant protein structure by enzymatic crosslinking is gaining an interest due to mild reaction conditions and the specificity of the enzymes. Since the functionality of a protein is determined by its molecular structure the enzymatic crosslinking of the protein has great potential to create different intra and inter molecular bonding to achieve texture and consumption experience without the need of using MC, gums and other additives. Exploring the effects of protein-protein crosslinking catalysed by enzymes such as transglutaminase, will be useful in understanding the effects it has on gelling, emulsifying, foaming, texturing properties of the extruded plant proteins.
A recent study showed that faba bean and oat proteins were successfully crosslinked by transglutaminase which improved the electrostatic stability. Transglutaminase-induced gels were also shown to have a high final storage modulus & strain hardening response indicating mechanically strong texture. This demonstrates the high potential of enzyme crosslinked proteins with good gelling capability which can be an alternative to commonly used gelling additives.
Proteins are converted to gels by a range of processes that increase intermolecular interactions. The prominent covalent interaction is disulfide bonds; however plant protein has limited amount of cysteine that contribute to the gel strength. Transglutaminase & other oxidative enzymes such as tyrosinase & laccase can potentially induce crosslinking of food proteins to improve textural properties
A lack of understanding on the optimum way of crosslinking the proteins by enzymes remains a challenge as food systems contain complex ingredients and involves a lot of processing.
We aim to develop a novel and chemical-free binding system for plant-based meat products as a replacement of currently used commercial binders/additives.
We will conduct a systematic study on the interactions between proteins and selected additives at molecular level to understand exactly how to create suitable textures for meat analogues. We will then focus on protein-protein crosslinking technologies, as a pre-treatment step to extrusion, to replicate such interactions and re-create the meat-like texture without
additives. We will also evaluate different plant based proteins for crosslinking performance, nutritional benefits, and costs to achieve the most optimal clean label solution.Research objectives
1.Achieve in-depth understanding of the chemistry of different proteins (e.g. pea, soy, chickpea, faba), enzymes (crosslinkers), & how the texture of current meat-alternative products is developed using additives.
2.Screen the tested proteins, enzymes, and processing parameters, via a structured design of experiment methodology. Generate predictive models to achieve optimal performance (e.g. texture, brittleness, elasticity) of crosslinked protein matrix.
3.Understand how crosslinked protein matrix behaves in model plant-based meat formula, & the impact of manufacturing process parameters (e.g. extrusion, high shear mixing, pasteurisation).
4.Conduct an extensive product validation program (in collaboration with industry partner), including large scale manufacture trials and sensory testing.