Legume Seed Protein Digestibility as Influenced by Traditional and Emerging Physical Processing Technologies

Abstract

The increased consumption of legume seeds as a strategy for enhancing food security, reducing malnutrition, and improving health outcomes on a global scale remains an ongoing subject of profound research interest. Legume seed proteins are rich in their dietary protein contents. However, coexisting with these proteins in the seed matrix are other components that inhibit protein digestibility. Thus, improving access to legume proteins often depends on the neutralisation of these inhibitors, which are collectively described as antinutrients or antinutritional factors. The determination of protein quality, which typically involves evaluating protein digestibility and essential amino acid content, is assessed using various methods, such as in vitro simulated gastrointestinal digestibility, protein digestibility-corrected amino acid score (IV-PDCAAS), and digestible indispensable amino acid score (DIAAS). Since most edible legumes are mainly available in their processed forms, an interrogation of these processing methods, which could be traditional (e.g., cooking, milling, extrusion, germination, and fermentation) or based on emerging technologies (e.g., high-pressure processing (HPP), ultrasound, irradiation, pulsed electric field (PEF), and microwave), is not only critical but also necessary given the capacity of processing methods to influence protein digestibility. Therefore, this timely and important review discusses how each of these processing methods affects legume seed digestibility, examines the potential for improvements, highlights the challenges posed by antinutritional factors, and suggests areas of focus for future research.

Protein Quality of Extruded Ready-to-Eat Baby Foods from Orange-Fleshed Sweet Potato, Amaranth Seeds, and Soybean Flour Blends

“…Thermal treatment boosts structural changes. Thermal treatment, however, has a considerable impact on non-polar interactions and intramolecular hydrogen bonds, changing the native structure (Ohanenye et al, 2022).…”

“…In a study carried out by Ohanenye et al (2022), it was found that after extrusion at 142°C, the tryptophan content dropped while the contents of valine, phenylalanine, and lysine dropped in peas. In a reversible reaction known as the early Maillard reaction, extrusion at high temperatures can lead to the condensation of the free amino groups of amino acids (or proteins/peptides) with the carbonyl group of reducing carbohydrates.…”

“…In a reversible reaction known as the early Maillard reaction, extrusion at high temperatures can lead to the condensation of the free amino groups of amino acids (or proteins/peptides) with the carbonyl group of reducing carbohydrates. The advanced Maillard reaction is irreversible, though, once the condensation has progressed to cyclization and the aldose produced in the early stages is converted to ketone in an irreversible reaction (Ohanenye et al, 2022).…”

Production, health‐promoting properties and characterization of bioactive peptides from cereal and legume grains

“…In order to ensure a more closely related digestion to that of the humans, which is dynamic, some modifications have been made to the method. These modifications include incorporation of different steps of digestion (mon‐, di‐, and multi‐step), addition of bile, consideration of transit and gastric emptying time, etc 36 . A common model of the method, which is recognized internationally due to its simplicity, reproducibility and low cost assessment is the INFOGEST method 36,37 .…”

“…The observed increase in peptide content thereafter may be due to production of peptides not suitable as a nitrogen source for the microorganisms. 56,57 On the contrary, 58 who evaluated the effect of fermentation time (12,24,36,48,60, and 72 h) on the peptide content of defatted wheat germ reported continual increase in peptide content till the 48 h before gradual decrease sets in. Therefore, the protein type and microorganisms involved may influence the degree of hydrolysis and hence the peptide content.…”