Abstract
Black soybeans were soaked in distilled water for 8 hours or in seasoned distilled water for 14 hours, and cooked in the same solution for 2 hours until they become tender. These two kinds of cooked soybeans were stored frozen at -18° for up to 4 weeks. Before freezing, the breaking strength was higher in the seasoned water cooked soybean than that in water only by Rheometer. This breaking strength of both samples decreased when stored frozen and thawed. The z-value obtained from the stress-deformation curve by a Rheometer increased after thawing. Optical and scanning electron micrography revealed that the intercellular space and the following deformation of cell wall could be seen after 2 weeks of freezing both in the seasoned water and water cooked soybean. These changes of cell structure were thought to cause tenderizing and stickiness after stored frozen. Change in texture was confirmed by sensory analysis. Panel members judged that the two weeks frozen soybeans cooked in water and in seasoned water were more tender, sticky and easy to peel. Cooked black soybean stored frozen and thawed until use is a useful way for home cooking.
