Submitted to: Cereal Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/9/2021
Publication Date: N/A
Interpretive Summary: Pea protein content and composition are regulated by a complex genetic mechanism involving multigene families. Protein content is reported to have negative correlations with starch content and seed yield. These factors may complicate breeding for quality in peas. Breeding for both protein and starch content together could be difficult. One of the most feasible breeding strategies could be to breed for specific end-uses (developing protein-specific and starch-specific varieties). As environmental variation are the major contributors to pea protein variation, breeders need to conduct multi-environment trials to develop cultivar for protein isolation. It seems also crucial, on growers’ side, to apply appropriate agronomic practices and select suitable environments to grow pea for protein extraction. Some genes involved in starch biosynthesis such as those determining wrinkled phenotype affected legumin composition. This affected protein composition and some of the functional properties like solubility and emulsifying property. Composition and functional properties of pea protein is significantly affected by protein isolation techniques. Research reports on functional properties of pea protein are limited to small number entries, which may indicate the need for including a wider range of germplasm from breeding programs and other genetic resources. Determination of quality of pea protein isolates involves measurement of several parameters, which may be impractical to do regularly in the breeding materials. Thus, it is crucial to integrate molecular breeding strategies such as marker-assisted selection (MAS) and genomic selection (GS) for pea protein and their functional properties.
Technical Abstract: Background and objectives Pea is cultivated in over millions of hectares worldwide and is one of the first-runner crops for plant-based proteins. Expanded market demand for pea proteins may necessitate targeted breeding to develop cultivars for plant-based protein. This, in turn, requires an understanding of the level of variation and the factors affecting the pea protein. Findings Reports indicated a wider variation for protein content in pea that primarily ranged from 20 to 30% and influenced by environmental and genetic factors. Protein-regulating genes per se directly and genes for starch biosynthesis indirectly play key roles in determine pea protein content and composition. Protein content is commonly reported to be negatively correlated with starch content and seed yield. Most research, even with a small number of entries, have demonstrated a broader variability for functional properties of pea protein. However, this was not close enough to identify the potential variation in the functional properties of protein in peas. Conclusions Because multiple genes and environmental variables are involved in influencing pea protein, critical designing of a breeding scheme is essential to improve pea for protein isolation. The economics of protein isolation necessitates a high-value use of the starch-rich by-product but improving protein and starch contents together may be complicated due to negative association of these two traits. Research reports suggested two strategies to improve pea seed quality, which are improving protein and starch together or targeting varieties for specific end-uses. Large-scale evaluation of the functional properties of protein in broader germplasm and the inclusion of molecular breeding approaches for pea protein may also be relevant. Significance and novelty This review discusses the variation in protein content, composition, and functional properties as well as the contributing environmental and genetic factors. It also explores the influence of starch biosynthesis genes to pea protein and a brief overview of protein fractionation methods. Potential research needs and breeding strategies are finally suggested for pea protein.