The changes in protein solubility and residual urease activity of soybean grains were studied under combined near-infrared radiation (NIR) and fluidized-bed drying at near-infrared radiation powers of 4-8 kW, air temperature of 40oC and air velocity of 4.5 m/s, soybean grains bed depth of 6 cm and initial moisture content of soybean grains of 20 % dry basis. The experimental results showed that raw soybean samples contained the protein solubility in the range of 90-92%. In drying process, the protein solubility was decreased with the increase of near-infrared radiation power and drying time. The final protein solubility of soybean samples in all drying conditions was in a range of 77-82%, which was above the standard requirement of 73% for the feed meal. In the case of residual urease activity, it was rapidly decreased in the early period and then remained steadily at 70, 52 and 39% of the initial activity under near-infrared radiation powers of 4, 6 and 8 kW, respectively. Additionally, the reduction of residual urease activity was correlated with the decrease in the moisture content of soybean grains. Keywords: fluidized-bed, near-infrared radiation, nutritional quality, soybean
Authors : Dondee, S.,Siriamornpun, S.,Meeso, N.
Book /Journal Title : Agricultural Sci. J. ;2010 / 41 / 281-284