More like the real meal - alternative plant-based proteins

Plant-based protein alternatives have arrived in the UK in a big way, where sales of meat-free alternatives are expected to exceed £1.1 billion by 2024. This has been driven by changing consumer attitudes and habits towards meat consumption, in part due to an increased global awareness of the impacts of traditional agricultural practices on climate change, on human health and on animal welfare. This, combined with the growing demand for food, and protein in particular, poses the question of where to source protein for human consumption. Plants and fungi may offer the answer, due to their lower carbon footprint and healthier nutritional profile compared to meat from livestock. Whilst traditional plant-based meat alternatives made from processed plant material, such as tofu, tempeh and seitan, have been eaten for centuries, in recent years plant-based meat analogues (PBMAs)^[1] have emerged as a new class of plant-based proteins.

Plant-based meat analogues (PBMAs)

PBMAs products are designed to mimic the sensory characteristics of conventional meat (taste, smell, texture and aesthetics), have a similar nutritional profile, and can be cooked or prepared using similar methods as used for animal meat products. They naturally contain lower levels of saturated fat and cholesterol, have fewer calories, and higher levels of micronutrients^[2],[3] and can contain protein levels comparable to conventional meat. They are distinct from plant-based meat alternatives, such as tofu, in that their aim is not simply to provide a plant-based protein source, but to closely mimic conventional meat - that is to say, they are not just an alternative to meat, but a like-for-like substitution. This blog explores the innovations behind the growing field of PBMAs.

The ingredients: protein sources & additives

The bulk of a PBMA is made up of plant proteins, commonly soy protein, pea protein, wheat protein and mycoproteins derived from fungi. Many of these are already used in traditional plant-based products such as tofu and seitan. In order to create a more “meat-like” experience, additives are used to enhance the PBMA. These include colourings, such as beetroot juice, and texture enhancers, such as polysaccharides and hydrocolloids. Among these, methylcellulose is regarded as an “essential hydrocolloid building block”^[4] that retains moisture and fat during heating. Without methylcellulose, PBMAs are vulnerable to “melting” during cooking - resulting in the somewhat undesirable outcome of turning burgers into soup.

Indeed, a lot of the ingredients used in PBMAs help to mimic the behaviour of conventional meat during cooking. For example, heat-stable caramel colouring agents, malt extracts and reducing sugars are added to make the PBMA transition from red to brown upon cooking^[5], mimicking the browning process of conventional meat. Soy leghemoglobin (SLH), an oxygen carrier similar to myoglobin in muscle, is an ingredient in Impossible Foods’ ‘Impossible Burger’ which, when heated, forms a red-tinted liquid that mimics the “bleed” seen in meat, as well as providing a characteristically metallic meat-like flavour^[6]. Meanwhile, pea-proteins can form heat-induced gels^[7] to encapsulate beetroot-based “blood” as in Beyond Meat’s ‘Beyond Burger’, allowing diners to order their plant burgers served medium-rare.

The processes

A fundamental characteristic of conventional meat is its fibrous nature, which contributes to its texture and mouthfeel. This is especially true for “whole muscle” meat like steak, but also of ground meat - however, it notably is not the case for plant proteins, which are typically globular. To mimic the anisotropic structure of conventional meat, the plant protein must be unfolded, cross-linked, and re-aligned to form fibres. Depending on the type of plant protein used as the starting material, the exact process required to do this varies^[8]. These processes can be split into “bottom-up” approaches, in which individual components are assembled together, and “top-down” approaches, in which blends of components are structured into fibres by applying external forces^[9]. “Bottom-up” processes include wet spinning and electrospinning, whereas “top-down” processes include extrusion, mixing of proteins with hydrocolloids, freeze structuring and shear cell technology^[10]. During extrusion, the protein solution is heated to a high temperature and mixed, before the mixture is cooled and sheared. These processes result in slightly different products: the high pressures and shear forces that the protein mixture is subjected to during extrusion influence the structural and chemical properties of the protein^[11], whereas freeze structuring a meat-like texture is obtained by freezing a protein emulsion and then removing the ice crystals, leaving a porous, fibrous microstructure^[12]. Whilst these processes are highly effective, there is a degree of trade-off, as “bottom-up” processes are considered superior in terms of mimicry of conventional meat, whereas “top-down” processes currently offer better scalability and efficiency^[13]. Different methods will need to be selected and optimised, depending on the final product.

PBMAs and IP: What can be protected?

On the back of huge market growth and large capital investment, the field of PBMAs is undeniably growing. In order to protect investments and recoup R&D costs, intellectual property protection is paramount. The multifactorial nature of PBMAs offers many opportunities for patent protection. For example, the novel ingredient combinations used for flavour and aroma may be covered by product patents. The processes used to alter the plant protein properties can also be protected, as well as the specific conditions used in these processes, such as temperature and pH. The plant-based meat analogue product itself can also be protected, and can be defined by its ingredients and composition, such as moisture content, as well as by the methods used to obtain them. In particular, methods for isolating and purifying the proteins from the raw plant material are prime subject-matter for protection by method claims.

New machines and production systems, such as bioreactors, incubators and shear cells, have been developed to make PBMAs with the required characteristics. These can be protected by product patents as well as patents covering their use in the production of PBMA products. Interestingly, it is likely that many of these patents will be relevant across multiple products - for example, bioreactors developed by an ersatz sausages company may find use in producing plant-based seafood - meaning that innovators could leverage or licence their patent portfolios not only over their competitors but over those producing non-competing products.

Conclusion

Ongoing work in this sector is set to further improve the meat-mimicry of these products. Focus is also on improving scalability, an important consideration for commercial feasibility. Further innovation is ongoing in developing new in situ analytical methods to follow the structuring process^[14], allowing a greater understanding of manufacturing steps. Continued efforts to reduce the environmental impact of the resources used and to improve the efficiency and reduce manufacturing costs will make PBMAs increasingly more competitive in price (as well as taste) compared to conventional meat.

References

1. Dekkers BL, Boom RM, van der Goot AJ. Structuring Processes for Meat Analogues. Trends Food Sci. Technol. 2018:81:25-36. Doi:10.1016/j.tifs.2018.08.011
2. Kumar, P., Chatli, M. K., Mehta, N., Singh, P., Malav, O. P. and Verma, A. K. (2017), ‘Meat analogues: Health promising sustainable meat substitutes’, Critical Reviews in Food Science and Nutrition, 57(5): pp. 923–32, doi:10.1080/10408398.2014.939739
3. Bohrer, B. M. (2017), ‘Review: Nutrient density and nutritional value of meat products and non-meat foods high in protein’, Trends in Food Science & Technology, 65: pp. 103–12, doi:10.1016/j.tifs.2017.04.016
4. Turner J. Hydrocolloids Create Successful Analogues. 2019. https://www.foodprocessing.com/articles/2019/hydrocolloids-create-successful-analogues/
5. He, J, Evans, NM, Liu, H, Shao, S. A review of research on plant‐based meat alternatives: Driving forces, history, manufacturing, and consumer attitudes. Compr Rev Food Sci Food Saf. 2020; 1– 18. https://doi.org/10.1111/1541-4337.12610
6. Fraser RZ, Shitut M, Agrawal P, Mendes O, Klapholz S. Safety Evaluation of Soy Leghemoglobin Protein Preparation Derived From Pichia pastoris, Intended for Use as a Flavor Catalyst in Plant-Based Meat. Int J Toxicol. 2018;37(3):241-262. doi:10.1177/1091581818766318
7. Ismail I, Hwang YH, Joo ST. Meat analog as future food: a review. J Anim Sci Technol. 2020;62(2):111-120. doi:10.5187/jast.2020.62.2.111
8. Ismail I, Hwang YH, Joo ST. Meat analog as future food: a review. J Anim Sci Technol. 2020;62(2):111-120. doi:10.5187/jast.2020.62.2.111
9. Pearson AM. Composition and structure. In: Meat and muscle biochemistry. 2012. ISBN 0323149294
10. Dekkers BL, Boom RM, van der Goot AJ. Structuring Processes for Meat Analogues. Trends Food Sci. Technol. 2018:81:25-36. Doi:10.1016/j.tifs.2018.08.011
11. Krintiras GA, Diaz JG, van der Goot AJ, Stankiewicz AI, Stefanidis GD. On the use of the Couette Cell technology for large scale production of textured soy-based meat replacers. J Food Eng. 2016:169:2015-213. Doi: https://doi.org/10.1016/j.jfoodeng.2015.08.021
12. Yuliarti O, Kovis TJK, Yi NJ. Structuring the meat analogue by using plant-based derived composites. J Food Eng. 2020:288. Doi: https://doi.org/10.1016/j.jfoodeng.2020.110138
13. Dekkers BL, Boom RM, van der Goot AJ. Structuring Processes for Meat Analogues. Trends Food Sci. Technol. 2018:81:25-36. Doi:10.1016/j.tifs.2018.08.011
14. Dekkers BL, Boom RM, van der Goot AJ. Structuring Processes for Meat Analogues. Trends Food Sci. Technol. 2018:81:25-36. Doi:10.1016/j.tifs.2018.08.011
    
    
    

Fay has also discussed this in New Food. View the article.