Extraction Treatments Affect Total Flavonoid and Phenolic Contents of Cowpea [Vigna unguiculata (L.) Walp.]
Eriyanto Yusnawan, Yuliantoro Baliadi

Indonesian Legumes and Tuber Crops Research Institute, Indonesian Agency for Agricultural Research and Development
Jalan Raya Kendalpayak Km 8 Malang East Java Indonesia

Abstract

Plant secondary metabolites exist during normal plant growth. The production increases remarkably when the plants are challenged to environmental stress. Quantification of these metabolites is affected by extraction solvents and preparation treatments. This study aims to select extraction solvents and treatments which are able to extract high total flavonoid and phenolic contents in cowpea seeds. Acetone at concentrations of 70 to 80 percents produced higher total flavonoid and phenolic contents of 10.37 to11.93 mg CE per g and 18.20 to 20.20 mg GAE per g in two cowpea cultivars. Antioxidant activities were in the range from 115.9 to 126.1 umol TE per g. Extraction of cowpea seeds using acidified 70 percent acetone produced similar amount of total phenolic contents to those of 70 to 80 percent acetone. Traditional extraction treatments of shaking and maceration extracted similar amount of the secondary metabolites. These simple extraction methods, therefore, could be suggested to extract flavonoid and phenolic contents as well as antioxidant activity in cowpea where the access to modern equipments is limited.

Keywords: cowpea, extraction, flavonoid, phenolic, secondary metabolite

Topic: AGRICULTURAL PRODUCT TECHNOLOGY