Whole-bean soymilk has been prepared by using media-milling. Some characteristics of media-milled soymilk have been determined and compared with filtered soymilk (similar to commercial ones) and whole-bean soymilk prepared by blending. There existed particles in the nano/submicrometer scale in both media-milled and filtered soymilk. The particles in blended soymilk were greater than 1 μm. Media-milled soymilk was the most stable among three samples, even after autoclaving. Solid recovery (98.44 ± 0.16%), viscosity (160.59 ± 4.26 cps), dietary fiber (22.68 ± 0.97% on dry basis), total polyphenol recovery (95.15 ± 7.09%), and isoflavone content (4.42 ± 0.03 mg/g dry solid) of media-milled samples were greater than those of filtered ones. Aglycones, the most bioactive form of isoflavone, in autoclaved media-milled soymilk were more than 2-fold those in autoclaved filtered soymilk. With almost no okara generated, the media-milled soymilk retained fiber in soybeans which would be beneficial to human health.
Keywords: isoflavone; media milling; soymilk; whole bean.