Characteristics of soybeans as affected by soaking conditions

The water absorption of soybeans in soaking is directly related to the changes in textural characteristics and grinding properties of soybeans for processing. In this study, we determined the characteristics of water absorption, solid loss, and moisture content, textural characteristics and grinding properties of soybeans at four different soaking temperatures, 10degreesC, 20degreesC, 30degreesC, and 40degreesC, and various soaking times up to 8 h. We found that the solid loss increased significantly when the soaking temperature increased from 30degreesC to 40degreesC. The measured moisture data of soaked soybeans fitted well with the data predicted using Peleg's equation. Rupture force and maximum tangent and secant modulus measured by the compression test decreased as the moisture increased, up to 122%. The grinding property of soaked soybeans was related only to the final moisture content and not to the soaking conditions. High soaking temperature could significantly reduce the required soaking time. Based on these results, we recommend that soybeans be soaked to minimal final moisture content of 120% before grinding. (C) 2003 Swiss Society of Food Science and Technology. Published by Elsevier Science Ltd. All rights reserved.