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 α-glucosidase inhibition activity of water extracts were evaluated. All the adzuki beans possessed strong ABTS.+ free-radical-scavenging capacity and α-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.