Characterization of starch-rich fraction obtained from wet protein isolation process in pea (Pisum sativum L.)

Authors: Daba, Sintayehu; McGee, Rebecca; Kiszonas, Alecia; Finnie, Sean

Submitted to: Legume Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/1/2024
Publication Date: 8/12/2024
Citation: Daba, S.D., Mcgee, R.J., Kiszonas, A., Finnie, S.M. 2024. Characterization of starch-rich fraction obtained from wet protein isolation process in pea (Pisum sativum L.). Legume Science. 6:e242. https://doi.org/10.1002/leg3.242.
DOI: https://doi.org/10.1002/leg3.242

Interpretive Summary: Pea seed mainly composed of starch (37-49%) and protein (21-33%) making it an important human diet, and these seed compositions can be fractionated using different approaches, mainly classified as dry and wet processes. Understanding properties of native starch from a particular biological source and modifying it can be important to facilitate its use in food processing. Starch modifications provide appropriate texture, quality, and shelf life as well as improved tolerance to processing conditions. This study provided valuable insights into properties of wet-pea starch fraction obtained though wet process, which can help the industry seeking value added processing for pea starch. The study also indicated that environmental conditions such as precipitation and temperature can play a role in determining starch properties and further studies are needed in this respect.

Technical Abstract: Protein isolation process yields protein and starch fractions. This article mainly focused on characterizing the starch fraction from five yellow pea entries grown at two locations (Pullman and Fairfield) over three seasons (2020-2022) for compositions, pasting properties, and gel firmness. Protein isolation yielded 17% and 60% protein and starch fractions, respectively, with starch purity of 71.5–79.9% for starch fractions. Pea starch exhibited a flat peak and high final viscosities compared to starches from cereals (corn and wheat). It also exhibited strong gel forming property. Pasting temperatures of starch fraction for the five pea entries were 74.9-75.6°C. Viscosity parameters for the 2020 and 2022 seasons were significantly higher than the 2021 season, which is reflected in the differences in weather conditions. The 2021 season saw remarkably low rainfall (April, May, and June) and high temperature (June and July). Multivariate analysis of 344 viscosity measurements during the RVA test clearly separated the 2021 samples from those of 2020 and 2022. In conclusion, weather affected starch properties, possibly because temperature and rainfall might affect starch biosynthesis genes in peas. This hypothesis requires further investigation.