Proximate, Anthocyanin and Oligomeric Proanthocyanidin Compositions of Cowpeas [Vigna unguiculata (L.) Walp] Cultivated in Southwest Japan

Cowpea (Vigna unguiculata) is one of the traditional ingredients of Japan. The objective of this study was to investigate the nutritional and chemical composition, and the biological activities of cowpea grown in Okinawa region, a subtropical area located in south west Japan. This study demonstrated that the protein and dietary fiber content of cowpea grown in the Okinawa region was similar to that of cowpeas grown in other countries. In addition, it was found that the sodium content and anthocyanin composition of cowpeas grown in the Okinawa region was different from that grown in other regions of Japan; however, no significant differences were observed in proanthocyanidin composition and content among the cowpeas grown in different cultivation areas in Japan.