Abstract
Investigations have been carried out to determine the influence of dry treatment after harvest on soybean seed qualities, i.e. physical property (percentages of perfect, break, wrinkled, and hard seed, weight of 1OO seeds, volume weight, and size of seed), chemical composition (protein, oil, carbohydrate, and ash content) and suitability for food processing (water absorption, germination, solid matter and protein in soaked water, protein extractability from ground seeds by hot water, increasing weight ratio by steaming, moisture content of steamed seeds, and softness and colour of steamed seeds). The samples were obtained at 2 different moisture stages (high moisture: 28-33% and low moisture: 20-21%). The high moisture non-threshed or threshed seeds were dried in natural air condition, and the high and low moisturc threshed seeds were dried in force air oven at 40°C and 60°C until the seeds moisture content became approximately 15%. On the physical properties, the more wrinkled seeds, lower volume-weight, and longer size of seed were observed in the heated-air dried seeds. However, the wrinkled seed was disappeared by soaking. On the chemical composition, the protein, oil, carbohydrate, and ash content was not affected by the heated-air drying. On the suitability for food processing, the ratio of water absorption was no change among the samples. On the other hand, remarkable reduction of the germination percentage was observed in the heated-air dried seeds, especially the high moisture seeds at harvesting. The solid matter and protein in soaked water were increased in heated-air dried seeds. The protein extractability was no change among the samples. On the steamed seeds, slight increase of the weight ratio and remarkable increase of the softness were observed in the heated-air dried seeds, and the softness remained at 30 minutes after steaming. On the color tone of the samples, differences were not observed among the color by naked eye and among the values of Y% and x, except y, by colorimeter.
