New Heating Method Makes Legumes Healthier and Easier To Digest

USask researchers discover radio frequency heating reduces antinutrients in peas and beans and improves energy efficiency.

Legumes such as peas and beans have been consumed by humans for hundreds of years, but at their core, they are the reproductive seeds of plants. To defend themselves from being eaten by animals or insects, these seeds produce natural compounds known as “antinutrients,” which are difficult for both animals – and humans – to digest.

Heating legumes helps break down these antinutritional compounds (including tannins, lectins, trypsin inhibitors, and phytic acid). However, the industrial ovens commonly used by food processors are not particularly effective. These machines often overheat the surface while the inner portion remains too cool to fully neutralize the antinutrients.

Radio frequency waves offer targeted heat

A research team in the Department of Chemical and Biological Engineering at the University of Saskatchewan (USask) has developed a promising alternative to conventional heating used in food processing. Their approach uses radio frequency (RF) waves and has shown greater effectiveness and energy efficiency than standard industrial methods.

PhD student Tolen Moirangthem explains how RF heating functions by drawing a comparison to microwave ovens. “When you put a cup of water in the microwave, the water heats up, but the cup doesn’t. The same is true for the pea—the water inside heats up, but the rest of the pea doesn’t.”

This technique is known as “selective heating” because it targets specific components within a substance rather than heating it evenly. The method appears to preserve important nutrients in peas and beans that are often degraded by traditional heat treatments. It also significantly reduces processing time, taking only a few minutes compared to much longer conventional methods.

Legume structure changed by RF heating

The team hypothesized that during RF heat treatment, the water inside a legume expands and turns into steam, which would cause the pores inside to explode from the pressure. In turn, this would create larger pores in the samples, as well as more pores in total, as the steam looked for ways to escape.

Using the Canadian Light Source at the USask, the research group confirmed that the beans treated with RF heat did in fact have more pores, and the heating method reduced the amount of an antinutrient (proteins called trypsin inhibitors)—by 81 per cent.

“We know that we have big potential with this project,” says Moirangthem. “Animal protein is very expensive in different parts of the world, so we need sustainable plant protein that can be produced at mass volume to feed the world population.”

This new heating method could help make bean and pea crops even more environmentally friendly to process, with the bonus of making legumes easier to digest.

Reference: “Experimental and computational study of synchrotron X-ray micro-computed tomography imaging in peas and pinto beans after radiofrequency heating” by Tolen Tombung Moirangthem, Adedayo B. Oke, Jarvis Stobbs, Micheal Nickerson and Oon-Doo Baik, June 2025, Innovative Food Science & Emerging Technologies.
DOI: 10.1016/j.ifset.2025.104033

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