Location: Plant Polymer Research2010 Annual Report
1a. Objectives (from AD-416)
Whereas the work published previously has been useful, we seek to look beyond what has been done in order to bring fresh perspectives and to open up new opportunities. We propose to take advantage of what is known about edible beans and explore three areas of application: energy, materials, and specialty chemicals.
1b. Approach (from AD-416)
We propose to carry out the initial work with neat, unextracted edible beans, because this is the fastest way to produce results. The next step is to carry out extractions. Some work is needed to determine the optimal extraction procedures. Thirdly, the different extracts will be studied for their commercial potential. Currently we plan to look at starch first, but the order of investigation may be changed during the study to optimize the efforts. Additional physical and/or chemical modifications may be needed to increase value of the extracts. In addition, some efforts will be expended to look at commercial potential of these various materials.
3. Progress Report
a. Study of total phenolics of eight beans We employed microwave-assisted extraction and found this method to be very effective for extracting phenolic constituents from eight bean types. Total phenolic contents determined by this method with water at 100oC were 2-3 times those determined by conventional extraction with water at the same temperature. This work has been published. b. Study of antioxidant content of eight beans Since beans are known to have good antioxidant properties, we carried out an analysis of antioxidants in both conventional heat and microwave-assisted extractions. In this case, microwave-assisted extraction gave results that depend strongly on extraction temperature, and correlation between total phenolics and antioxidant behavior was not found. On the other hand, conventional heat extraction gave more reasonable results with a fair correlation between total phenolics and antioxidant levels. We are submitting a manuscript for publication. c. Oils from beans Because of the much lower amount of oil in common beans, the bean oils and their nutritional benefits have often been overlooked. We evaluated the oils in four beans, determined their chemical composition including fatty acid profile, tocopherol content, oxidative stability, and other physical properties. Beside the high level of polyunsaturated fatty acid responsible for high iodine value, we found these beans oils to contain very high levels of tocopherols (and other antioxidants) which may be responsible for their unusually high oxidative stability. d. Extrusion of beans The common extrusion equipment (Brabender) in our facility at NCAUR was successfully used to provide a combination of high-temperature, pressure, and shearing-stress for processing defatted whole beans. Relatively fewer investigations have been done on the whole seeds of common beans due to the difficulty of extrusion. Yet in this study, we managed to determine their physicochemical and functional properties (e.g., color, water solubility, oil absorption capacity, total starch, starch digestibility) of extrudates of four defatted-whole common beans and the effects of variables such as extrusion temperature, feed moisture and screw speed. e. Ethanol production from bean Most of the work has been done. A manuscript is being prepared. The Authorized Departmental Officer's Designated Representative monitored progress through the annual progress report.
Sutivisedsak, N., Cheng, H.N., Willett, J.L., Tangsrud, R., Lesch, W.C., Biswas, A. 2009. Effect of Microwave Extraction on Phenolic Content of Beans. Food Research International. Available online at: http://dx.doi.org/10.1016/j.foodres.2009.09.014.