Australian plant proteins_food australia_Oct-Dec_2022

STUDENT CONTRIBUTION

Australian plant proteins: towards healthy and sustainable food production Words by Woojeong Kim, Rishi Ravindra Naik and Drs Yong Wang and Cordelia Selomulya

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s estimated by the Food and Agriculture Organisation, humans will have to increase food production by 60% to keep up with the current population explosion, expected to reach > 9 billion by 2050.1 The stress on increasing food production also presents an opportunity to incorporate different nutrient-rich and native food sources in our diets.

Proteins, both plant and animal based, are one of the vital elements for human wellbeing, and increasing the production of such components has been a major area of research around the globe. Australia, being one of the global producers of animal based proteins, is still unable to satisfy the ever-growing demand and needs to tap into the potential plantprotein market.1 According to a global plant protein market survey,2 this sector currently stands at US$14 billion, and is predicted to grow to > US$16 billion by 2026, which could be a major prospect for job creation and improvement of the gross domestic product of our nation.

While several local companies have already invested in this sector, including v2food, All G Foods, Eighth Day Foods, Fenn Foods and Fable

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Food, Australia has the opportunity to be a leader in plant protein production by investing in research and development which supports the incorporation of different native crops for the production of commercial plant proteins.3 Here, we report on the utilisation of Australian plant proteins in the food industry covering food sources, processing technologies and potential applications. Investigating the latest trends of the Australian plant protein market provides a direction to move forward in both research and commercialisation and allows food developers to design better plant-based food products.

Australian plant-based food proteins A report from CSIRO4 shows Australia has significantly progressed with the plant-based food market during the past decade by promoting the use of unique proteins from pulses and seeds locally produced in the region. Most of these plant proteins can be divided into two major groups based on their utilisation as commercial and emerging plant proteins. Examples of commercial plant proteins are wheat, pea, soy and rice proteins, while

emerging plant protein candidates include chickpeas, lentils, field beans, faba-beans, amaranth, hemp and some fungi, roots and fruit sources.

These proteins are used for the production of various ingredients such as flours, concentrates, isolates and texturised proteins.4 In terms of food manufacturing in Australia, wheat production (~1014% protein) generated 36.3 million tonnes in 2021, which is utilised for noodles, breads and other baked products. Soy protein, as one of the major plant proteins containing > 35% protein, is mainly used as an ingredient in plant-based milk and protein bars.4 The demand for these common plant proteins has been declining due to their potential allergenic properties.5 The issue with allergenicity has opened up the opportunity to explore non-traditional plant proteins for commercialisation including amaranth, chickpeas, lentils, field beans, faba-beans, hemp, lupin, rye and potato proteins.

Most plant protein ingredients comprise different protein fractions including globulins, albumins, glutelins and prolamins, or subfractions including convicilins, vicilins and legumins. The distribution

of the protein fractions determines the techno-functional attributes including solubility, emulsifying and foaming properties, and gelation of a particular ingredient.6 For example, the seed storage proteins from pulses, mainly consisting of 7S and 11S globulin fractions, are often employed as natural emulsifiers to stabilise oil-inwater emulsions.7 In this case, the 7S protein is a dominating fraction for stabilising oil/water interface with more flexible structure, compared to 11S protein with a higher molecular weight and more ordered structure.8 Extraction and processing techniques enable the protein fractions to be disassociated or aggregated, thereby greatly affecting the protein structure and functionality.

Innovative processing strategies for plant protein functionality Novel protein processing techniques are essential for successful application and commercialisation of plant proteins, for use in plantbased products with excellent taste, nutrition, texture and quality. Since commercial plant proteins often have low solubility and poor sensory profiles due to protein denaturation during isolation and recovery, postprocessing strategies have recently been proposed in the food industry for developing semi-solid and liquid formulations.

Protein blends and plant proteinpolysaccharide complex are both emerging approaches to improve plant protein functionality. The plant and dairy proteins in protein blends can form isopeptide bond, disulphide bond, hydrogen bond and hydrophobic interaction through physicochemical reactions such as heating and enzyme treatment.7 They have shown potential in applications for various food formulations such as gels, emulsions, foams and powder. In addition, plant proteinpolysaccharide conjugates formed

by Maillard glycation show selective functionality enhancement according to the conjugate formation stages.

Figure 1. Depiction of plant proteins, processing and their applications.

To date, the approach has only been tried on a few plant protein sources including soybean, pea, rice or wheat, with further studies needed to determine its potential as a treatment option for Australian plant protein sources.9 Our recent study on plant/dairy protein blends demonstrated that the addition of polysaccharide (sodium alginate) could improve the stability of pea/whey protein-stabilised emulsions in a wide pH range from weak acid to alkaline by forming electrostatic protein-polysaccharide complex and/or enhancing the viscosity of the colloids.10 Interestingly, alginate addition prevented pea protein from being displaced at the oil/water interface over time, and the disulphide bond between pea and whey proteins was formed at high pH. Current work focuses on how the enzymatic cross-linking between pea and whey proteins could enhance the emulsion stability and encapsulation of oilbased bioactive compounds.

Another strategy for enhancing plant protein functionality is the formation of protein-polysaccharide Maillard conjugates. Maillard conjugation or glycation uses the initial stages of the Maillard reaction (the reaction that ‘browns’ bread upon baking) forming Schiff’s base, resulting in the structural modification of protein by coupling it with reducing sugars of carbohydrate.9 In our recent

study with a non-traditional plant protein, amaranth was conjugated with a seaweed polysaccharide, resulting in improved solubility and other functional attributes including water and oil holding capacity. This approach is being further explored for upscaling by our research group at UNSW Sydney.

Potential applications of Australian plantbased proteins The application of plant proteins has expanded into new food ingredients, functional beverages, dairy and meat alternatives, with novel technologies including pulsed electric processing, ultrasound processing, high pressure processing and others in the past decade.11 The Australian food industry is striving to produce high-quality plant proteins, while much effort is still needed in research and development for texture and flavour enhancement when applying plantbased ingredients to produce new products.

Spray drying is the instantaneous drying of the atomised droplets in contact with the heated air.12 The production of different types of powders via spray drying, including encapsulation of nutraceutical and oilbased active ingredients using plant proteins, could expand their use as food ingredients. Plant/dairy protein blends could be a new material with applications in beverages or dairy alternatives for those consumers who

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STUDENT CONTRIBUTION

14. Wang, Y., & Selomulya, C. (2022). Food rheology applications of large amplitude oscillation shear (LAOS). Trends in Food Science & Technology.

15. Sha, L. and Y.L. Xiong, Plant protein-based alternatives of reconstructed meat: Science, technology, and challenges. Trends in Food Science & Technology, 2020. 102: p. 51-61.

are in transition to a plant-based diet.13 Understanding the gelation of plant proteins using rheology can help enhance the organoleptic texture of dairy and meat alternatives.14 Plant proteins commonly used in commercial plant-based food products include soybeans, pea, wheat, potato, mung bean and rice proteins. Processing techniques, such as extrusion and aggregation through heating, are imperative for some plant proteins with native globular structure to form meat-like textures.15 Plant protein gelation can imitate the texture of egg, cheese, and seafood by shaping both homogeneous and heterogeneous structures.

Texturisation of plant proteins by gelation could overcome the drawbacks caused by traditional extrusion technology, such as nutrient and flavour losses and limitation on the use of plant-based food ingredients.

Furthermore, incorporation of other food ingredients including fat and polysaccharides as thickening agents, and adhering agents such as transglutaminase while developing sustainable processes, could be the strategy for structural alteration of plant proteins and the production of high-quality plant-based food products.

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References 1. Da Silva, J.G., Feeding the world sustainably. UN Chronicle, 2012. 49(2): p. 15-17.

2. Mordor Intelligence, 2022. Global plant protein market report. [online] https://www. mordorintelligence.com/industry-reports/globalplant-protein-market, Accessed 30 July 2022.

3. Buxton, A., New AU$378 Million project launches to transform South Australia into a plant protein manufacturing powerhouse. Green Queen. [online] Available at https://www.greenqueen. com.hk/south-australia-plant-protein-productionhub/, Accessed 30 July 2022.

4. CSIRO, 2022. Australia’s Protein Roadmap. [online] Available at https://www.csiro.au/en/ work-with-us/services/consultancy-strategicadvice-services/CSIRO-futures/Agriculture-andFood/Australias-Protein-Roadmap, Accessed 31 July 2022.

5. Shewry, P.R., et al., Plant protein families and their relationships to food allergy. Biochemical Society Transactions, 2002. 30(6): p. 906-910.

6. Sim, S.Y.J., et al., Plant proteins for future foods: A roadmap. Foods, 2021. 10(8): p. 1967.

7. Kim, W., Y. Wang, and C. Selomulya, Dairy and plant proteins as natural food emulsifiers. Trends in Food Science & Technology, 2020. 105: p. 261272.

8. Drusch, S., M. Klost, and H. Kieserling, Current knowledge on the interfacial behaviour limits our understanding of plant protein functionality in emulsions. Current Opinion in Colloid & Interface Science, 2021. 56: p. 101503.

9. Naik, R.R., Y. Wang, and C. Selomulya, Improvements of plant protein functionalities

by Maillard conjugation and Maillard reaction products. Critical Reviews in Food Science and Nutrition, 2021: p. 1-26.

10. Kim, W., Y. Wang, and C. Selomulya, Impact of sodium alginate on binary whey/pea proteinstabilised emulsions. Journal of Food Engineering, 2022. 321: p. 110978.

11. Sá, A.G.A., et al., Influence of emerging technologies on the utilization of plant proteins.

Frontiers in Nutrition, 2022. 9.

12. Wang, Y. and C. Selomulya, Spray drying strategy for encapsulation of bioactive peptide powders for food applications. Advanced Powder Technology, 2020. 31(1): p. 409-415.

13. Guyomarc’h, F., et al., Mixing milk, egg and plant resources to obtain safe and tasty foods with environmental and health benefits. Trends in Food Science & Technology, 2021. 108: p. 119-132.

Ms Woojeong Kim is a PhD candidate in the School of Chemical Engineering at UNSW Sydney. Her PhD research is on encapsulating bioactive compounds using food ingredients such as protein, polysaccharide and their combinations. She primarily investigates improving the functionality of plant protein using dairy/plant protein blends, focusing on protein interaction, structural modification and food application, including spray dried powder.

Mr Rishi Naik is a PhD candidate from the School of Chemical Engineering, UNSW Sydney. His research involves utilisation of Maillard conjugation and other novel techniques for improving the functional properties of emerging plant proteins. He is also keen on implementing different simulations and modelling-based strategies in food science and engineering.

Dr Yong Wang is Senior Research Associate with the School of Chemical Engineering, UNSW Sydney. Prior to joining UNSW, he had eight years of R&D experience in the food industry. His research area includes food processing technology and food rheology.

Professor Cordelia Selomulya joined UNSW Sydney in late 2019 as a Professor in the School of Chemical Engineering and as the Research and Commercialisation Director of the Future Food Systems CRC. She is leading a research group with an internationally recognised reputation in drying technology research, particularly for food and dairy applications. She is a Fellow of the Australian Academy of Technology and Engineering (ATSE) and Institution of Chemical Engineers (IChemE). f