Compared digestibility of plant protein isolates by using the INFOGEST digestion protocol. (November 2020)

• Record Type: Journal Article
• Authors: Santos-Hernández, Marta; Alfieri, Fabio; Gallo, Veronica; Miralles, Beatriz; Masi, Paolo; Romano, Annalisa; Ferranti, Pasquale; Recio, Isidra
• Is Part Of: Food research international. Volume 137(2020)
• Publication Date: 2020-11
• Subjects: Protein isolate -- Garden pea -- Grass pea -- Soybean -- Lentil -- Casein -- Whey protein -- Gastrointestinal digestion -- Epitopes; Food -- Analysis -- Periodicals; Food industry and trade -- Periodicals; Food industry and trade -- Canada -- Periodicals; Food Technology -- Periodicals; Food -- Periodicals; Food-Processing Industry -- Periodicals; Aliments -- Industrie et commerce -- Périodiques; Aliments -- Industrie et commerce -- Canada -- Périodiques; Aliments -- Recherche -- Périodiques; Food industry and trade; Canada; Periodicals; Electronic journals; 664.005
• DOI: 10.1016/j.foodres.2020.109708
• Languages: English
• ISSNs: 0963-9969

Abstract

Graphical abstract: Highlights: Digested pea and lentil isolates showed similar soluble nitrogen to milk proteins. After digestion 70–76% of the nitrogen fraction corresponds to peptides. Leu, Lys, Arg and Phe were abundant free amino acids in plant protein digests. Some plant proteins are resistant to pepsin but degraded by intestinal enzymes. Resistant peptides to digestion matched with reported epitopes. Abstract: The use of ingredients based on plant protein isolates is being promoted due to sustainability and health reasons. However, it is necessary to explore the behaviour of plant protein isolates during gastrointestinal digestion including the profile of released free amino acids and the characterization of resistant domains to gastrointestinal digestion. The aim of the present study was to monitor protein degradation of four legume protein isolates: garden pea, grass pea, soybean and lentil, using the harmonized Infogest in vitro digestion protocol. In vitro digests were characterized regarding protein, peptide and free amino acid content. Soybean was the protein isolate with the highest percentage of insoluble nitrogen at the end of the digestion (12%), being this fraction rich in hydrophobic amino acids. Free amino acids were mainly released during the intestinal digestion, comprising 21–24% of the total nitrogen content, while the percentage of nitrogen corresponding to peptides ranged from 66 to 76%. Legume globulins were resistant to gastric digestion whereas they were hydrolysed into peptides and amino acids during the intestinal phase. However, the molecular weight (MW) distribution demonstrated that all intestinal digests, except those from soybean, contained peptides with MW > 4 kDa at the end of gastrointestinal digestion. The profile of free amino acids released during digestion supports legume protein isolates as an excellent source of essential amino acids to be used in protein-rich food products. Peptides released during digestion matched with previously reported epitopes from the same plant species or others, explaining the ability to induce allergic reactions and cross-linked reactivity.