From Oil Mill Waste to Superfood: The Hidden Protein Goldmine in Seed Byproducts

Every year, the world’s vegetable oil industry grinds through millions of tonnes of soybeans, rapeseed, sunflower seeds, sesame, peanuts, flaxseed, hempseed, pumpkin seed and cottonseed. After the oil is pressed out, what remains—defatted cakes and meals—has long been treated as low-value animal feed or, worse, waste. A new review published in Food Science and Biotechnology argues that this mountain of byproducts is one of the most underappreciated resources in modern food science: a rich reservoir of functional proteins and bioactive peptides that could reshape how we formulate plant-based foods, nutraceuticals and even biomedical ingredients. The authors, led by Yvonne Yve Wen Thoe of the Analytical Biochemistry Research Centre at Universiti Sains Malaysia, together with colleagues at Universitas Brawijaya in Indonesia, systematically map the technologies, enzymatic tools and food applications that are turning oil mill leftovers into high-value ingredients.

The core of the review’s argument rests on two protein families that dominate oilseed meals: globulins and albumins. Globulins, the salt-soluble storage proteins that include the well-characterized 7S and 11S fractions of soybean, and albumins, the water-soluble fraction, possess exactly the technofunctional properties that food formulators crave. They stabilize emulsions, whip into foams and form gels—the three pillars of texture in everything from plant-based yogurts to meat analogues. Recent work highlighted in the review shows that the ratio between these fractions matters enormously: soybean varieties with different 11S/7S globulin ratios display markedly different structural and functional behavior, meaning breeders and processors can, in principle, tune raw material quality at the source. Similar fraction-specific behavior has been documented in rice bran, where enzymatic hydrolysis of albumin and globulin fractions alters their emulsification performance in distinct ways.

Getting those proteins out of the meal, however, is where the engineering gets interesting. Traditional alkaline extraction followed by isoelectric precipitation works, but it can damage protein structure and leave behind antinutritional compounds. The review identifies a clear trend toward non-conventional extraction technologies that are gentler, faster and often more scalable. Ultrasound-assisted extraction uses cavitation bubbles to rupture cell walls and loosen protein matrices, boosting yields from pumpkin seed press cake and chickpea flour alike. Microwave pretreatment accelerates solvent penetration and has been optimized for perilla meal protein using response surface methodology. Pulsed electric fields permeabilize seed tissue through electroporation, improving the alkaline extraction of valuable compounds from perilla seed meal, while high-pressure homogenization and dynamic high-pressure microfluidization physically shear protein aggregates—flaxseed protein isolates treated this way show reduced aggregation and enhanced functional properties.

Perhaps the most chemically inventive approaches involve alternative solvent systems. Reverse micelle extraction, in which proteins are solubilized inside surfactant-stabilized nanodroplets within an organic phase, has been applied to hemp protein isolate, with the defatting process itself influencing protein structure, functionality and aromatic profile. Deep eutectic solvents—designer mixtures of hydrogen bond donors and acceptors that behave like ionic liquids but are far less toxic—have emerged as green media for protein extraction, and molecular dynamics simulations are now revealing exactly how natural deep eutectic solvents act on rapeseed proteins at the atomic level. In cottonseed processing, deep eutectic solvents have even been used to integrate protein extraction with detoxification, simultaneously pulling out protein and removing gossypol, the toxic phenolic pigment that has historically limited cottonseed’s food use. Ultrasonic-aided extraction combined with degossypolization has similarly produced cottonseed meal protein with improved functional traits and modified molecular structure.

Once extracted, whole proteins are only half the story. The second act of the review concerns bioactive peptides: short amino acid chains, typically two to twenty residues, released when proteins are cleaved by enzymes. Enzymatic hydrolysis with proteases such as alcalase and pepsin liberates sequences that can do far more than nourish. The catalogue of activities reported for oilseed-derived peptides is striking: antioxidant effects that protect cells from oxidative damage, inhibition of angiotensin-converting enzyme (ACE) linked to blood pressure reduction, blockade of dipeptidyl peptidase-IV (DPP-IV) and α-glucosidase relevant to diabetes management, anti-inflammatory signaling in human cell lines, cholesterol-lowering effects, and antimicrobial action. Cottonseed protein hydrolysates, for example, have demonstrated antioxidant, antimicrobial and ACE-inhibitory activity, while peanut protein hydrolyzed by alcalase inhibits both ACE and renin. Pumpkin seed meal hydrolysates have yielded novel ACE-inhibitory peptides that also upregulate ACE2, and sunflower seed peptide fractions separated by ultrafiltration show hypocholesterolemic and antidiabetic potential.

Some of the most compelling evidence comes from precisely identified peptide sequences. Hempseed peptides WVSPLAGRT and IGFLIIWV have been shown to exert anti-inflammatory activity in LPS-stimulated human hepatic cells, and the same IGFLIIWV sequence—dubbed peptide H3—lowers cholesterol in a human hepatic cell line. A flaxseed-derived peptide called IPPF inhibits intestinal cholesterol absorption in Caco-2 cells and hepatic cholesterol synthesis in HepG2 cells. Novel antioxidant peptides purified from peanut meal protect liver cells against hydrogen peroxide-induced oxidative damage, and a soybean meal peptide has been shown to alleviate oxidative stress through the Keap1-Nrf2-HO-1 signaling pathway. Sunflower seed-derived peptides have progressed all the way from in silico simulation to animal models, showing antioxidant and anti-inflammatory activity in vivo—a critical step beyond test-tube chemistry.

What makes the current moment different, the authors emphasize, is the arrival of computational discovery. Rather than hydrolyzing proteins and screening the resulting soup laboriously, researchers now combine enzymatic hydrolysis with artificial intelligence-assisted peptide screening tools, molecular docking and machine learning classifiers. Deep learning frameworks for antioxidant peptide discovery, updated machine learning tools for predicting anticancer peptides, and improved toxicity predictors such as ToxinPred 3.0 allow scientists to mine protein sequences in silico, rank candidate peptides by likely activity and safety, and then validate only the most promising ones experimentally. Machine learning is also transforming antimicrobial peptide identification and design, a field where rational design has long been hampered by the complexity of structure–activity relationships. This computational pipeline dramatically compresses the discovery timeline, turning oilseed proteomes into searchable databases of therapeutic potential.

The food applications flowing from this research are already tangible. Rapeseed meal protein isolate has been tested as a supplement in texture-modified foods for the elderly, addressing a genuine clinical need for protein-dense, easy-to-swallow nutrition. Sesame seed press cake protein has been formulated into meatball analogues, and hydrolyzed sesame meal protein, free and encapsulated, has been incorporated into chitosan-based coatings that extend the shelf life of ostrich fillets. Pumpkin seed protein-based hydrogels are being used as gelatin mimics and edible inks in 3D-printed foods, while pumpkin seed protein serves as a carrier that stabilizes astaxanthin, a notoriously unstable carotenoid. Plant proteins are fortifying oat yogurt with improved storage stability and bioactivity, and hempseed protein emulsions are being stabilized through carefully chosen enzymatic treatments that modify the interfacial adsorption layer. Even the residual fiber left after rapeseed protein extraction is being characterized as a functional ingredient, and flaxseed oil cake hydrolysates have found a surprising second life as media supplements in CHO cell culture for biopharmaceutical manufacturing.

The review is candid about the obstacles standing between laboratory promise and supermarket shelves. Bioavailability remains the central question: a peptide that inhibits ACE in a assay must survive stomach acid, digestive enzymes and the intestinal barrier to have any chance of acting in the body, and simulated digestion studies show that activity can change substantially along the way. Bitterness is a persistent sensory problem, since hydrophobic peptides—the very sequences often responsible for bioactivity—also activate bitter taste receptors, and bioinformatics is increasingly deployed to understand and predict peptide bitterness. Storage stability within real food matrices, the effects of processing and fortification on peptide integrity, allergenicity concerns that hydrolysis can either mitigate or complicate, regulatory pathways for novel food ingredients, and the sheer economics of commercialization all demand attention before oilseed peptides become mainstream functional ingredients.

Still, the trajectory is unmistakable. With the global population projected to approach nearly ten billion by mid-century and demand for sustainable protein intensifying, the review positions oilseed byproducts as a resource the food industry can no longer afford to discard. The convergence of green extraction technologies, precision enzymology, AI-driven peptide discovery and a growing body of in vivo validation suggests that the defatted cake sitting in an oil mill today could become tomorrow’s emulsifier in a plant-based cheese, the antihypertensive ingredient in a functional beverage, or the bioactive payload in a nutraceutical capsule. What was once waste, the authors argue, is now a strategic raw material—and the science of unlocking it is advancing on every front at once.

Subject of Research: Functional proteins and bioactive peptides from oilseed processing byproducts

Article Title: Oilseed processing byproducts as sources of functional proteins and bioactive peptides: extraction technologies, enzymatic hydrolysis, and food applications

Article References: Thoe, Y. Y. W., Yap, P.-G., Gan, C.-Y., Setyawan, H. Y., & Huda, N. (2026). Oilseed processing byproducts as sources of functional proteins and bioactive peptides: extraction technologies, enzymatic hydrolysis, and food applications. Food Science and Biotechnology. https://doi.org/10.1007/s10068-026-02333-3

Image Credits: AI Generated

DOI: 10.1007/s10068-026-02333-3

Keywords: oilseed byproducts, bioactive peptides, functional proteins, protein extraction, enzymatic hydrolysis, ultrasound-assisted extraction, deep eutectic solvents, ACE-inhibitory peptides, plant-based foods, food science, artificial intelligence, sustainability