Comprehensive evaluation of nutritional components and antioxidant activity of buckwheat germplasm resources

【Objective】This study aimed to comprehensively evaluate the nutritional components and antioxidant acti-vity of different buckwheat germplasm resources， providing theoretical basis for identifying specialized buckwheat varie-ties and their processing and utilization.【Method】A total of 10 tartary buckwheat and 27 common buckwheat germplasms were taken as materials to determine their total protein content， total phenolic content， total flavonoid content， total starch content， 1,1-diphenyl-2-picrylhydrazyl （DPPH） radical scavenging capability， 2,2'-azino-bis（3-ethylbenzothiazoline-6-sulfonic acid） diammonium salt （ABTS） radical scavenging capability， and total antioxidant capability. The genetic variation analysis， correlation analysis， principal component analysis， and cluster analysis were performed.【Result】Diversity analysis results showed that the total protein content， total phenolic content， total flavonoid content， total starch content， DPPH radical scavenging capability， ABTS radical scavenging capability， and total antioxidant capability of tartary buckwheat were all higher than those of common buckwheat. The coefficient of variation of tartary buckwheat germplasms ranged from 2.27% to 49.36%， among which the ABTS radical scavenging capability exhibited the highest coefficient of variation， while the total protein content showed the lowest coefficient of variation. The coefficient of variation of common buckwheat germplasms ranged from 4.62% to 35.19%， with relatively high values for total flavonoid content and DPPH radical scavenging capability （>30%）， and the lowest value for total protein content. Correlation analysis revealed that， in tartary buckwheat and common buckwheat， total phenolic content was significantly positively correlated with total flavonoid content， and DPPH radical scavenging capability was significantly positively correlated with ABTS radical scavenging capability（P<0.01）； no significant correlations were observed between total protein content or total starch content and other traits （P>0.05）. Principal component analysis （PCA） and cluster analysis showed that the cumulative variance contribution rates of the first three principal components were 83.9% for tartary buckwheat and 78.6% for common buckwheat. In tartary buckwheat， Group Ⅰ could serve as candidate materials for breeding varieties of high total protein content and high total starch content， Group Ⅱ could serve as hybrid parents for genetic analysis of total protein， total phenolic， and total starch traits， and Group Ⅲ could serve as candidate materials for breeding varieties of high total phenolic content， high total flavonoid content， and high antioxidant activity. In common buckwheat， Group Ⅰ could serve as candidate materials for breeding varieties of high total protein content and high total flavonoid content， Group Ⅱ could serve as candidate materials for breeding varieties of high total antioxidant capability， and Group Ⅲ could serve as candidate materials for breeding varieties of high total phenolic content， high total starch content， and high DPPH and ABTS radical scavenging capabilities.【Conclusion】The ABTS radical scavenging capability in tartary buckwheat， as well as the total flavonoid content and DPPH radical scavenging capability in common buckwheat exhibit rich genetic variation and can serve as target traits for specialized excellent germplasms. The phenolic and radical scavenging capability factor， total antioxidant factor， and nutritional component factor in tartary buckwheat， along with the phenolic and antioxidant activity factor， and total protein factor in common buckwheat， extracted by principal component analysis， can be used as core indicators for the comprehensive evaluation of buckwheat quality. Buckwheat germplasms from different groups can be utilized for the screening and application of specialized varieties with high protein content， high starch content， high phenolic content， and high antioxidant capability.