Rice milling byproducts offer new protein sources for plant-based cheesemaking
A peer-reviewed study published in Future Foods has characterised proteins extracted from three rice milling fractions – brown rice, broken kernels and rice bran – derived from a single cultivar, and assessed their performance in plant-based cheese prototypes. The research establishes clear links between protein subunit composition, functional properties and cheesemaking outcomes, pointing to new applications for rice processing byproducts.
Mahfuzur Rahman is an assistant professor of food science with the Arkansas Agricultural Experiment Station and the Dale Bumpers College of Agricultural, Food and Life Sciences at the University of Arkansas.
© UADA photo
Researchers at the Arkansas Agricultural Experiment Station have demonstrated that proteins isolated from three distinct fractions of a single rice cultivar exhibit sufficiently different functional properties to warrant consideration as individual ingredients in plant-based food formulations. The study, led by assistant professor Mahfuzur Rahman and graduate student Ruslan Mehadi Galib at the University of Arkansas, compares brown rice, broken kernel and rice bran proteins – all byproducts of white rice milling – and evaluates their performance in standardised cheese prototypes.
The work examines protein quality not across cultivars, but within a single one. As Rahman noted: “In a single rice grain, we have three different types of protein – from brown rice, white rice and bran. That’s the fundamental understanding we wanted to develop. When you say, ‘rice protein,’ what does that mean? Is it brown rice protein? Bran protein? Broken kernel protein?”
Subunit composition drives functional differences
Proteins were extracted via alkali-acid precipitation from cultivar RT3202, with subunit profiles characterised using Osborne fractionation, SDS-PAGE and size-exclusion chromatography. Rice bran showed the highest albumin content at 25.78%, whilst broken kernel protein was dominated by glutelin at 66.64%. Brown rice protein presented the most balanced subunit distribution, with albumin at 14.11% and glutelin at 47.29%.
These compositional differences translated directly into divergent functional profiles. Brown rice protein demonstrated the highest solubility (18.37%), emulsifying activity (81%) and oil-holding capacity (163.79 g/100 g dry basis), attributed to its balanced subunit profile and higher hydrophilic amino acid content. Rice bran protein exhibited the highest surface hydrophobicity (43.18) and water-holding capacity (68.27 g/100 g), with
elevated β-sheet content (26.98%) driving an inverse relationship between hydrophobicity and solubility through protein aggregation. Brown rice protein also achieved the highest in vitro gastric digestibility at 67.61%, whilst rice bran protein scored lowest at 60.42% – linked to its elevated insoluble fibre content impeding enzymatic access during pancreatic digestion. All three fractions contain the nine essential amino acids, classifying them as complete proteins.
Cheese prototype performance
Cheese prototypes were formulated using 12% protein, 22.5% organic coconut oil, 12.5% waxy corn starch and 53% water, with chickpea protein as a control. Broken kernel protein produced the softest cheese with the highest meltability (38.32%) but also the greatest oil separation (104.48%). The authors note that although it formed a stable initial emulsion, the protein “fails to retain fat during thermal processing, leading to fat migration and a softer melt.” Brown rice protein yielded a firmer texture and intermediate meltability (24.95%), whilst rice bran protein delivered the lowest oil separation (69.43%) and enhanced water retention, attributed to its protein–fibre matrix. All rice-based prototypes contained approximately 12% protein – notable given that plant-based cheese commonly lacks meaningful protein content.
Commercial and sustainability implications
The research carries implications for domestic protein sourcing within US rice processing. Arkansas harvested a record 1.43 million acres in 2024, accounting for nearly 50% of national production. The US generates approximately 12.2 million metric tonnes of rice bran and 22.5 million metric tonnes of broken kernels annually – a potential yield of around 3 million metric tonnes of protein. Currently, companies import and distribute rice protein for the domestic market, and the researchers argue that utilising milling byproducts presents “a significant opportunity to expand the US-based rice protein market while promoting a sustainable circular economy.” The hypo-allergenic nature of rice protein – free from dairy, nuts and gluten – adds further commercial relevance.
Limitations
Proteins were extracted using hexane-based defatting, and Rahman is currently developing ultrasound-based non-chemical extraction methods. The authors state that “subsequent study ought to concentrate on refining cheese compositions and assessing their sensory characteristics, customer acceptance, and shelf-life stability,” with “current research in progress to tackle these issues, facilitating the transition from laboratory development to practical use.”
Reference
Galib, R. M., & Rahman, M. M. (2026). Three shades of plant protein from a single rice cultivar: Insights into subunit profiles, molecular structures, functional and nutritional properties, and cheesemaking performance. Future Foods, 13, 100875. https://doi.org/10.1016/j.fufo.2025.100875
Food scientists with the Arkansas Agricultural Experiment Station investigated proteins from three parts of a single rice cultivar for plant-based cheesemaking and discovered each source offered different qualities.
© UADA photo
