Abstract
The physical property, chemical composition, and suitability for food processing of soybean seeds were investigated on the seeds by dry treatment after harvest, i.e. natural drying and air drying by non-heated and heated at 20°C, 30°C, and 40°C. The seeds stored at 15°C with R.H. 65% and 75%, at 30°C with R.H. 65% and 75%, and room storage with paper bag for 30, 60, 120, 130, 270, and 360 days, respectively, were further investigated on suitability for food processing. The moisture contents of seeds under the storage were as follows: R.H. 65%: 10.7% to 11.4% at 15°C and 9.6% to 10.5% at 30°C, R.H. 75%: 14.5% to 14.9% at 15°C and 13.8% to 15.1% at 30°C, and room storage: 8.3% to 12.7%, respectively. On the changes of suitability for food proccssing by storage, absorbability of water in seeds, germinability, extractability of protein by hot water from soaked seeds, pH of soybean milk, and increasing weight ratio of steamed seeds to raw seeds were decreased, while soluble matter and protein in soaked water, and moisture content, hardness and coloration of steamed seeds were increased. Among the stored conditions, the seeds at 15°C with R.H. 65%, 75%, and room storage well retained the suitability for food processing, whereas remarkable deteriorations were observed at 30°C with R.H. 75%. Among the heated-air drying seeds, the influence of storage for food processing was significantly observed in the seeds dried at 40°C. From the results, the undesirable influence of storage was observed on Miso, Natto, or cooked beans making as compared with Tofu making.
