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Presscakes & Biproducts

Upcycling Protein- and Fiber-Rich Food Byproducts

The world’s largest food industries create excesses of plant material – byproducts – during their production processes. The macronutrient profile of many of these byproducts is similar and ripe for valorization: primarily fiber and protein. Take the oil industry as an example. Canola/rapeseed and sunflower oil production alone are projected to generate about 78 million tonnes of presscake globally in 2026/2027.1 The brewing industry, likewise, produces about 37.8 million tonnes of spent grain annually.2 Soy okara alone – a byproduct of soymilk and tofu production – is estimated at about 14 million tonnes per year.3 Many such examples exist, but these three industries alone produce byproducts which contain roughly 34-35 million tonnes of pure protein annually.4 Not taking into account projected growth – as newly industrializing countries increase consumption of refined products – the opportunity for upcycling these byproducts is enormous.

To focus only on protein, let’s reframe the opportunity in terms of per capita consumption. Using a simple estimate of 50 grams of protein per person per day, or 18.25 kg per year, that amount of protein generated as waste by just these three industries could theoretically cover the baseline annual protein needs of about 1.8–2.0 billion adults.5 A rough market comparison makes the point even clearer. If this same amount of protein were replaced with a low-cost commodity protein such as soybean meal, it would be worth roughly $22 billion at recent global prices.6 This does not mean all of these by-products can immediately become human food. Processing losses, food safety, digestibility, and regulations are important. But of utmost importance is consumer acceptability, that is, deliciousness. To underscore this point, take the equivalent economic impact of replacing protein for which there is additional demand. If replaced with chicken meat protein, the equivalent protein value would be closer to $600 billion.7 If replaced with beef protein, it could exceed $1.4 trillion.8

If we can efficiently process these byproducts into delicious consumer products, the gains are profound both environmentally and economically. Life-cycle research on food waste management shows that conventional waste pathways can create significant environmental burdens, including greenhouse gas emissions, while circular reuse and valorization can recover nutrients and reduce the need for new raw materials.910 Reviews of waste-to-protein systems also argue that food-safe and feed-safe side streams from food and drink industries can become a meaningful part of future protein supply, provided that they are transformed into products people actually want to eat.11 The economic case is also clear: the global protein ingredients market is estimated at about $58–72 billion in 2026 and is projected to keep growing, meaning these byproducts sit next to a large and expanding market for functional protein ingredients.1213

Let’s take a brief look at these three byproducts, which we believe can be made exceptionally delicious:

1. Brewers’ Spent Grain, or BSG

Brewers’ spent grain is the leftover malt and grain produced after beer is brewed. During brewing, sugars are extracted from malted grains for fermentation, and the wet grain that remains becomes BSG. It is often fairly neutral, malty, and grain-like in flavor, though some streams can be darker, roasted, or bitter depending on the brewing process and whether hop residues are mixed in.2

BSG is the largest solid by-product of brewing, representing about 85% of beer-specific waste by weight. About 20 kg of wet BSG is produced for every 100 liters of beer. It is usually 70–80% water, which makes it heavy, perishable, and difficult to transport. On a dry basis, it contains roughly 20–22% protein, along with a large amount of fiber.2

Most BSG is currently used as animal feed, with smaller amounts going to biogas or landfill. That is useful, but it is often still a low-value use.14

2. Presscakes from Oil Production

Oilseed presscakes are the solid materials left after oil is removed from seeds. The main examples here are canola/rapeseed presscake and sunflower presscake, though peanut, camelina, sesame, flax, coconut, and other oilseed cakes are also important in different regions. Once much of the oil is removed, the remaining material is mostly protein, dietary fiber, carbohydrates, minerals, and plant compounds.15

Canola/rapeseed and sunflower are especially important because they are produced at huge scale. USDA data project about 53.26 million tonnes of rapeseed meal and 24.76 million tonnes of sunflower seed meal globally in 2026/27.1 Rapeseed oil cake can contain around 42.8% crude protein, while sunflower oilseed cake can contain around 35.6% crude protein.15 Together, those two meals alone contain roughly 31.6 million tonnes of protein per year, enough in theory to meet the baseline annual protein needs of about 1.7 billion adults.45

The challenge is that these presscakes are not automatically delicious or easy to use. Canola and rapeseed can contain bitter or pungent compounds, especially glucosinolates, along with other compounds that affect flavor and digestibility. Sunflower presscake can be more approachable, but its valorization is non-trivial.1516

3. Lees from Plant-Based Milk and Similar Products

Plant-based milk and tofu production also create leftover pulp, often called lees, okara, or plant-based milk residue. This happens when soybeans, oats, almonds, rice, peas, or other plant materials are soaked, ground, and filtered. The liquid becomes the milk or tofu base, while the leftover pulp still contains protein, fiber, fat, minerals, and carbohydrates.3

Soy okara is the best-studied example. Fresh okara is about 70–80% water, but on a dry basis it contains around 25–30% protein and 40–60% dietary fiber. About 1.1 kg of okara can be produced for every 1 kg of soymilk or tofu, with global production estimated at about 14 million tonnes per year. In protein-equivalent terms, soy okara alone may contain enough protein to meet the baseline annual needs of about 40–70 million adults.345

These residues vary depending on the crop. Soy okara is different from oat lees, almond pulp, pea residue, or rice residue, because each has its own proteins, carbohydrates, flavors, textures, and processing behavior. But they share the same basic opportunity: they are wet, perishable, protein- and fiber-rich side-streams that could become useful food ingredients instead of being treated as waste or a low rung product such as animal feed.311

How We Are Experimenting with Upcycling These Products

One promising direction is garum, shoyu, and miso production. Through fermentation with koji, these byproducts can be transformed into savory products without the need for highly intensive processing. In shoyu- and garum-style fermentations, the byproducts can often be used in relatively whole forms. Koji organisms such as Aspergillus oryzae produce proteases and other enzymes that break proteins into smaller peptides and amino acids, including glutamates, which are central to the taste of umami.17 This makes fermentation especially useful for materials such as brewers’ spent grain, canola presscake, sunflower presscake, and okara, because it can transform bland, bitter, or fibrous side-streams into deeply savory ingredients. For miso-style products, minimal physical processing may still be useful; for example, wet grinding can reduce graininess and create a smoother texture. As examples of this work, see Canola Presscake Garum and (ONG) Sunflower Presscake Miso.

A second direction is solid-state fermentation, including koji, tempeh-style fermentation, oncom-style fermentation, and basidiomycete cultivation. These methods are promising because they can act directly on moist, fibrous substrates and can change both nutrition and texture. Fungal fermentation can improve flavor, bind particles together, modify fiber structure, and create meatier textures.18 Some fungal and yeast processes can also increase savory nucleotide compounds such as IMP and GMP, which work with glutamate to intensify umami.19 This makes solid-state fermentation especially relevant for turning BSG, okara, and oilseed presscakes into meat alternatives or savory bases rather than simply extracting protein from them.

A third direction is enzymatic processing for protein and fiber flavor upcycling. Instead of trying to hide the flavors of these byproducts, enzymes can be used to unlock roasted, savory, nutty, malty, cocoa-like, or coffee-like notes. This is especially relevant for chocolate and coffee alternatives, where the goal is not just nutrition but flavor creation. Enzymatic and fermentation-based processing can release amino acids, sugars, peptides, and aroma precursors that later contribute to browning, roasted flavors, and complex aroma development.20 For some of our work in this direction, see Coffee & Chocolate Substitutes.

Bibliography

Footnotes

  1. USDA Foreign Agricultural Service. Oilseeds: World Markets and Trade. July 2026. https://apps.fas.usda.gov/psdonline/circulars/oilseeds.pdf ↩ ↩2

  2. Dancker, P., Glas, K., and Gastl, M. “Potential Utilisation Methods for Brewer’s Spent Grain: A Review.” International Journal of Food Science & Technology, vol. 60, no. 1, 2025, article vvae022. https://academic.oup.com/ijfst/article/60/1/vvae022/7943327 ↩ ↩2 ↩3

  3. Rohrer, K., Whitfield, F., Aussanasuwannakul, A., Ningrum, A., Hugi, C., and Breitenmoser, L. “Comparative Screening Life Cycle Assessments of Okara Valorisation Scenarios.” Environments, vol. 12, no. 3, 2025, article 93. https://www.mdpi.com/2076-3298/12/3/93 ↩ ↩2 ↩3 ↩4

  4. Author calculation from cited production and composition figures. BSG protein estimate: 37.8 Mt wet BSG × 20–30% dry matter × 20–22% protein ≈ 1.5–2.5 Mt protein/year. Rapeseed/sunflower estimate: roughly 53 Mt rapeseed meal × 42.8% protein + roughly 25 Mt sunflower meal × 35.6% protein ≈ 31.6 Mt protein/year. Soy okara estimate: 14 Mt wet okara × 20–30% dry matter × 25–30% protein ≈ 0.7–1.3 Mt protein/year. Total ≈ 34–35 Mt protein/year. ↩ ↩2 ↩3

  5. U.S. Food and Drug Administration. 21 CFR §101.9(c)(7)(iii). Protein Daily Value: 50 g for adults and children 4 years and older. https://www.law.cornell.edu/cfr/text/21/101.9 ↩ ↩2 ↩3

  6. Federal Reserve Bank of St. Louis / International Monetary Fund. “Global price of Soybean Meal.” FRED series PSMEAUSDM. June 2026 observation: $296.15939 per metric tonne. https://fred.stlouisfed.org/series/PSMEAUSDM/ ↩

  7. Federal Reserve Bank of St. Louis / International Monetary Fund. “Global price of Poultry.” FRED series PPOULTUSDM. June 2026 observation: 167.12391 U.S. cents per pound. https://fred.stlouisfed.org/series/PPOULTUSDM ↩

  8. Federal Reserve Bank of St. Louis / International Monetary Fund. “Global price of Beef.” FRED series PBEEFUSDM. June 2026 observation: 341.60227 U.S. cents per pound. https://fred.stlouisfed.org/series/PBEEFUSDM ↩

  9. Roy, P., and Mohanty, A. K. “A Review on the Challenges and Choices for Food Waste Valorization: Environmental and Economic Impacts.” ACS Environmental Au, vol. 3, no. 2, 2023, pp. 58–75. DOI: 10.1021/acsenvironau.2c00050. https://pmc.ncbi.nlm.nih.gov/articles/PMC10021016/ ↩

  10. U.S. Environmental Protection Agency. From Field to Bin: The Environmental Impacts of U.S. Food Waste Management Pathways. https://www.epa.gov/land-research/field-bin-environmental-impacts-us-food-waste-management-pathways ↩

  11. Piercy, E., Verstraete, W., Ellis, P. R., Banks, M., Rockström, J., Smith, P., Witard, O. C., Hallett, J., Hogstrand, C., Knott, G., Karwati, A., Rasoarahona, H. F., Leslie, A., He, Y., and Guo, M. “A Sustainable Waste-to-Protein System to Maximise Waste Resource Utilisation for Developing Food- and Feed-Grade Protein Solutions.” Green Chemistry, vol. 25, 2023, pp. 808–832. DOI: 10.1039/D2GC03095K. https://pubs.rsc.org/en/content/articlehtml/2023/gc/d2gc03095k ↩ ↩2

  12. Grand View Research. “Protein Ingredients Market Size, Share & Trends Analysis Report.” https://www.grandviewresearch.com/industry-analysis/protein-ingredients-market ↩

  13. Fortune Business Insights. “Protein Ingredients Market Size, Share & Industry Analysis, 2026–2034.” https://www.fortunebusinessinsights.com/protein-ingredients-market-115863 ↩

  14. Terefe, G. “Preservation Techniques and Their Effect on Nutritional Values and Microbial Population of Brewer’s Spent Grain: A Review.” CABI Agriculture and Bioscience, vol. 3, 2022, article 51. https://link.springer.com/article/10.1186/s43170-022-00120-8 ↩

  15. Vichare, S. A., and Morya, S. M. “Exploring Waste Utilization Potential: Nutritional, Functional and Medicinal Properties of Oilseed Cakes.” Frontiers in Food Science and Technology, vol. 4, 2024, article 1441029. https://www.frontiersin.org/journals/food-science-and-technology/articles/10.3389/frfst.2024.1441029/full ↩ ↩2 ↩3

  16. Tan, S. H., Mailer, R. J., Blanchard, C. L., and Agboola, S. O. “Canola Proteins for Human Consumption: Extraction, Profile, and Functional Properties.” Journal of Food Science, vol. 76, no. 1, 2011, pp. R16–R28. DOI: 10.1111/j.1750-3841.2010.01930.x. https://ift.onlinelibrary.wiley.com/doi/10.1111/j.1750-3841.2010.01930.x ↩

  17. Kitamoto, K. “Molecular Biology of the Koji Molds.” Advances in Applied Microbiology, vol. 51, 2002, pp. 129–153. DOI: 10.1016/S0065-2164(02)51004-2. ↩

  18. Nout, M. J. R., and Kiers, J. L. “Tempe Fermentation, Innovation and Functionality: Update into the Third Millennium.” Journal of Applied Microbiology, vol. 98, no. 4, 2005, pp. 789–805. DOI: 10.1111/j.1365-2672.2004.02471.x. ↩

  19. Ninomiya, K. “Natural Occurrence.” Food Reviews International, vol. 14, no. 2–3, 1998, pp. 177–211. DOI: 10.1080/87559129809541157. ↩

  20. Wösten, H. A. B. “Filamentous Fungi for the Production of Enzymes, Chemicals and Materials.” Current Opinion in Biotechnology, vol. 59, 2019, pp. 65–70. DOI: 10.1016/j.copbio.2019.02.010. ↩