Trait associations and genetic variability in field pea (Pisum sativum L.): Implications in variety development process

Authors: Daba, Sintayehu; McGee, Rebecca; Morris, Craig

Submitted to: Cereal Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/20/2021
Publication Date: 3/10/2022
Citation: Daba, S.D., McGee, R.J., Morris, C.F. 2022. Trait associations and genetic variability in field pea (Pisum sativum L.): Implications in variety development process. Cereal Chemistry. 99(2):355-367. https://doi.org/10.1002/cche.10496.
DOI: https://doi.org/10.1002/cche.10496

Interpretive Summary: Pea is a leading one of the crops for plant-based protein production, and it has been used in a variety of applications, including food supplements, emulsifiers, fortified beverages, protein blends, and encapsulations. Pea demand has risen in recent years in the United States, thanks in part to Beyond Meat, a plant-based meat company that uses pea protein as its primary ingredient. In 2017, the global market for pea protein was US$32 million, and it is predicted to be worth US$176 million by 2025. Flour, protein concentrate, protein isolate, and texturized protein products are the pea protein ingredients used in food processing. Our findings show that a significant amount of pea seed was lost during the pre-extraction and extraction processes. After losses from dehulling, milling, and protein extraction, only about 14.6% of the original pea seed could end up in the protein isolate. In other words, a considerable amount of the pea seed was lost as hull, starch-rich byproduct, and soluble components in the precipitation step of the protein extraction process. These could have a significant impact on the economics of pea protein isolation. To improve the profitability of pea protein extraction, it is critical to find greater values for hull and starch-rich byproduct. Bioenergy crops (cereals, sugars, and oil crops), agricultural residue (wood and grass), postconsumer waste (municipal solid waste), and forest products (fuelwood, wood processing residue) are all potential biofuel feedstocks. The pea hull and starch-rich byproduct of the protein extraction process can also be used to produce biofuel. Starch production could be another option of using the starch-rich byproduct.

Technical Abstract: Pea research and breeding for protein extraction are likely to play an important role as the demand for pea protein is in the rising. Developing pea cultivars with high protein content could be a top breeding priority. Identification of the traits to select for and understanding of the relationships between traits may be required for optimizing the breeding process. Protein was extracted from 26 green and 30 yellow pea genotypes grown in four and two environments, respectively. Results indicated that about 15.7% of the seed was made comprised of hull for the 56 pea genotypes, with a low of 10.1% and a high of 20.4%. The protein content of split pea flour was varied between 18.9% and 29.3%. Compared to whole pea flour, split-pea flour had a 1.4% higher protein content. Fairfield had the highest mean flour protein content of any of the locations studied. Protein isolate yield ranged from 14.8% to 21.1%, with a mean of 17.8%. Protein recovery from split pea flour ranged from 49.7% to 68.9% across all pea types, with a mean of 58.4%. On average, about 55.9% of the initial sample ended up in the starch-rich byproduct fraction, with the remaining 26.3% lost as a soluble material during the extraction process. The correlation analysis indicated that flour protein content was positively correlated with protein isolate yield and purity while negatively with yield of starch-rich byproduct. These correlations imply that the protein content of flour could be used in the selection process, and that increasing protein content reduces the loss as byproduct during the extraction process. Further studies are required to understand the relationships of protein isolate yield and purity with functional properties of protein.