Submitted to: International Journal of Food, Agriculture, and the Environment
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/6/2012
Publication Date: 1/15/2012
Publication URL: http://handle.nal.usda.gov/10113/55057
Citation: Biswas, A., Sutivisedsak, N., Cheng, H.N., Willett, J.L., Lesch, W.C., Tangsrud, R.R. 2012. Extraction and analysis of antioxidant capacity in eight edible beans. International Journal of Food, Agriculture, and the Environment. 10(1):89-96. Interpretive Summary: In this work, we discovered that extraction with microwave irradiation is an effective method for the determination of extractable antioxidant capacity of beans which is associated with many health benefits of beans. In general, higher extraction temperature resulted in higher antioxidant activity of the extracts. Eight beans were chosen that are important for North Dakota and Minnesota. This discovery will benefit bean growers from North Dakota and Minnesota who funded this research.
Technical Abstract: In this work we explored the use of microwave as a fast method for the extraction of antioxidants from beans. Antioxidant capacity of the extracts from meat and the hull of eight common beans was determined, using the ß-carotene bleaching method. Microwave-assisted extraction was achieved using two solvents: 50:50 ethanol/water or 100% ethanol. In general, higher extraction temperature resulted in higher antioxidant activity of the extracts. The hull extracts exhibited more antioxidant activity than the meat extracts. In most cases, the 50:50 ethanol: water extraction tended to produce more antioxidants than 100% ethanol. The most effective microwave-assisted extraction system was found for 50:50 ethanol:water at 150ºC. Across the eight beans, there was no correlation between the total phenolic content and antioxidant activity because different phenolics in different beans contributed differently to antioxidant activity. However, within the data of each bean type, the total phenolic content did correlate with antioxidant activity. The correlations were strongest for hull data and for 50:50 ethanol:water as the extraction solvent. The weakest correlations were found for navy and great northern beans probably because these two beans had low levels of flavonoids and anthocyanins.