Examination of the functional properties, protein quality, and iron bioavailability of low phytate pea protein ingredients

Authors: CHIGWEDERE, CLAIRE - University Of Saskatchewan; STONE, ANDREA - University Of Saskatchewan; KONIECZNY, DELLANEY - University Of Saskatchewan; LINDSAY, DONNA - University Of Saskatchewan; HUAN, SHAOMING - University Of Saskatchewan; Glahn, Raymond; HOUSE, JAMES - University Of Manitoba; WARKENTIN, THOMASA - University Of Saskatchewan; NICKERSON, MICHAEL - University Of Saskatchewan

Submitted to: European Food Research and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/25/2023
Publication Date: 3/22/2023
Citation: Chigwedere, C., Stone, A., Konieczny, D., Lindsay, D., Huan, S., Glahn, R.P., House, J., Warkentin, T., Nickerson, M. 2023. Examination of the functional properties, protein quality, and iron bioavailability of low phytate pea protein ingredients. European Food Research and Technology. 249:1517-1529. https://doi.org/10.1007/s00217-023-04232-x.
DOI: https://doi.org/10.1007/s00217-023-04232-x

Interpretive Summary: Pea products represent an emerging and highly profitable component for pea growers. Consumers, food scientists and nutritionists are keenly interested in the nutritional quality of peas and pea products. Therefore, The effect of seed phytate content (regular and low) on the composition (protein and mineral content), protein quality (in vitro protein digestibility corrected amino acid score (IVPDCAAS)), iron bioavailability, and functionality (solubility, oil/water holding capacity, foaming capacity and stability, emulsion stability) of pea flours and extracted protein isolates was investigated. There was 37-45% less phytate in the flours of the low phytate varieties compared to the regular varieties and approximately 39% less for the isolates. Upon extraction of protein, phytate increased over three-fold, but for the mineral ions this was selective in that Fe2+ ions increased more than three-fold whilst Ca2+ content halved. The phytate content did not influence the IVPDCAAS of the flours or isolates. The functional properties of the isolates and flours were largely similar between the low and regular phytate varieties. For each variety, iron was more bioavailable in the flours (10.5-22.0 ng ferritin/mg protein) than in the isolates (2.9-16.5 ng/mg). The low phytate flours (20.6 ng/mg) had overall higher iron bioavailability than the regular phytate pea flours (10.7 ng/mg). For the isolates this trend was not significant, possibly due to high intra-variety variation and the limited number of samples; however, the mean iron bioavailability value of the three low phytate isolates was three times greater than that of the two regular phytate isolates. In conclusion, protein isolates extracted from low phytate varieties did not show deleterious or positive impacts on the functional characteristics or protein quality; more evidence is required for iron bioavailability

Technical Abstract: The effect of seed phytate content (regular and low) on the composition (protein and mineral content), protein quality (in vitro protein digestibility corrected amino acid score (IVPDCAAS)), iron bioavailability, and functionality (solubility, oil/water holding capacity, foaming capacity and stability, emulsion stability) of pea flours and extracted protein isolates was investigated. There was 37-45% less phytate in the flours of the low phytate varieties compared to the regular varieties and approximately 39% less for the isolates. Upon extraction of protein, phytate increased over three-fold, but for the mineral ions this was selective in that Fe2+ ions increased more than three-fold whilst Ca2+ content halved. The phytate content did not influence the IVPDCAAS of the flours or isolates. The functional properties of the isolates and flours were largely similar between the low and regular phytate varieties. For each variety, iron was more bioavailable in the flours (10.5-22.0 ng ferritin/mg protein) than in the isolates (2.9-16.5 ng/mg). The low phytate flours (20.6 ng/mg) had overall higher iron bioavailability than the regular phytate pea flours (10.7 ng/mg). For the isolates this trend was not significant, possibly due to high intra-variety variation and the limited number of samples; however, the mean iron bioavailability value of the three low phytate isolates was three times greater than that of the two regular phytate isolates. In conclusion, protein isolates extracted from low phytate varieties did not show deleterious or positive impacts on the functional characteristics or protein quality; more evidence is required for iron bioavailability.