Phenotypic diversity of pea (Pisum sativum L.) varieties and the polyphenols, flavonoids, and antioxidant activity of their seeds

Pea (Pisum sativum L.) is the fourth leading legume crop in the world, and its demand is increasing. In this study, the morphological characteristics (seed shape, seed surface, seed coat color, hilum color, cotyledon color, 100-seed weight and color values), total phenolic content (TPC), total flavonoid content (TFC), 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS) free radical scavenging capacity and ferric reducing antioxidant power (FRAP) of 75 pea cultivars were investigated. Results showed rich genetic diversity and a wide range of phenolic contents and antioxidant activities. Sixteen varieties enriched with phenolic contents and high antioxidant activities were screened out. A significant correlation was reported among color values, TPC, TFC, ABTS and FRAP. Principal component analysis (PCA) extracted four principal components with a total cumulative contribution of 81.29%. Hierarchical cluster analysis based on the four extracted principal components resulted in a dendrogram dividing the peas into three groups. In addition, dark pea seeds have potential as a functional food in addition to their traditional role in providing dietary protein and fibre. This study provided a scientific basis for the breeding of pea varieties, development of new products and improvement of pea resource utilization.