Nutritional composition and biological activities of 17 Chinese adzuki bean (Vigna angularis) varieties

Seventeen Chinese adzuki (Vignaumbellata.) bean varieties were collected and milled. The nutritional compositions including starch, fat, protein and phytochemicals were analyzed. Results obtained showed that these adzuki beans have a high content of resistant starch which accounts for about 23.57% of total starch, and have suitable amino acid constitutions. Palmitic acid (27.68%), linoleic acid (33.11%) and linolenic acid (26.61%) were the dominant fatty acids. Besides, four bound phenolic acid and two free phenolic acids were identified by HPLC. The antioxidant activity of 70% ethanol extracts and a-glucosidase inhibition activity of water extracts were evaluated. All the adzuki beans possessed strong ABTS(.+) free-radical-scavenging capacity and a-glucosidase inhibition activity. Significant positive correlations (P < .01) of the antioxidant activity with total phenolic acids, total flavonoids and free caffeic acid contents were observed. These results are anticipated to providing useful information on the development of adzuki bean-based functional food.