Real ileal amino acid digestibility of pea protein compared to casein in healthy humans: a randomized trial

Abstract

Background It is necessary to propose plant alternatives to animal proteins that are of good nutritional quality. Pea is a good candidate owing to its high protein content and its well-balanced amino acid (AA) profile. Objectives This study aimed to assess the real ileal AA and nitrogen digestibility (RIDAA and RIDN) of pea protein isolate as compared to milk casein in humans. It also aimed to evaluate their nutritional quality through calculation of the digestible indispensable amino acid score (DIAAS) and to determine the net postprandial protein utilization (NPPU). Methods Fifteen healthy volunteers were included in a randomized, single-blinded, 2-arm, parallel-design trial. They were equipped with a naso-ileal tube. They ingested the test meals, which consisted of 9 successive portions of mashed potatoes containing either pea protein or casein, intrinsically labeled with nitrogen 15. Ileal content, plasma, and urine samples were collected regularly over an 8-h postprandial period. Results The mean RIDAA values were 93.6% ± 2.9% for pea protein and 96.8% ± 1.0% for casein, with no difference between the sources (P = 0.22). Leucine, valine, lysine, and phenylalanine were significantly less digestible in pea than in casein. The RIDN values were 92.0% ± 2.7% and 94.0% ± 1.7% for pea protein and casein, respectively, and were not different (P = 0.11). The DIAAS was 1.00 for pea protein and 1.45 for casein. The NPPU was 71.6% ± 6.2% and 71.2% ± 4.9% for pea protein and casein, respectively (P = 0.88). Conclusions Although some AAs are less digestible in pea protein than in casein, the real ileal digestibility and the NPPU were not different. The DIAAS of 1.00 obtained for pea protein demonstrated its ability to meet all AA requirements. This study shows the potential of pea isolate as a high-quality protein. This study was registered at clinicaltrials.gov as NCT04072770.

Protein Quality in Perspective: A Review of Protein Quality Metrics and Their Applications

“…Overall, ileal digesta from humans are thus most preferred for assessment of protein quality. Some studies have indeed been conducted in humans to determine the ileal digestibility of proteins [ 64 , 65 , 66 ]. However, ileal digesta collection in human is complicated [ 67 ], and most data available to date on ileal digestibility of dietary proteins has come from animal models [ 68 ].…”

Evaluation of structure, quality, physicochemical properties, and phenolics content of pea proteins: A novel strategy through the incorporation of fermentation

“…In addition, Guillin et al. (2022) demonstrated that the water solubility of chickpeas noticed a significant increase from 10.5% to 17% following a 24‐h fermentation process supported by LAB.…”

“…In a recent study by Gantumur et al (2023), the authors demonstrated that the solubility of proteins in water can increase from ∼89% to ∼95% by employing protein breakdown treatment using Saccharomyces cerevisiae yeast during fermentation. In addition, Guillin et al (2022) demonstrated that the water solubility of chickpeas noticed a significant increase from 10.5% to 17% following a 24-h fermentation process supported by LAB.…”

“…No significant (p > 0.05) changes were observed in the digestibility after 48 h of fermentation (Table 1). Alrosan et al (2023a) and Guillin et al (2022) reported that fermentation by LAB releases protein hydrolysis enzymes during the fermentation process, resulting in smaller protein fragments, including peptides and amino acids, which subsequently enhances the protein digestibility. Researchers have discovered that Lactobacillus can hydrolyse proteins into oligopeptides, which the body can absorb more readily (Azi et al, 2020;Randazzo et al, 2016).…”

The role of dietary plant and animal protein intakes on mitigating sarcopenia risk

“…As an example, consuming pea protein isolate for16 weeks elicited similar digestibility, utilization, and effects on nitrogen balance as casein and whey in aged rats [ 10 ]. In healthy women and men receiving naso-ileal tube feedings, the digestibility and indispensable amino acid availability of pea protein extract was comparable to casein, with certain limitations for leucine, lysine, valine, and phenylalanine [ 11 ▪ ]. Similarly, 30 g milk protein ingestion resulted in quicker and overall greater increases in plasma leucine, lysine, methionine, and total amino acid concentrations over 5 h post ingestion, compared to ingesting 30 g potato-derived protein [ 12 ▪ ].…”