Drying and ripening of soybeans for benefication of soybean products
The object of this investigation was to ripen and dry soybeans in such a way as to prevent the formation of bad taste and odor in the oil.
Field run soybeans were treated in specially constructed gas-tight silos through which mixtures of air, carbon dioxide, and ethylene in varying concentrations were recirculated for the purpose of maturing and stabilizing the beans and to prevent peroxidases action, the latter being credited with imparting the offensive odor and taste to the oil and meal obtained by processing the bean.
Nine silos were run simultaneously with nine different mixes of gases varying between 90 to 35% ethylene and 10 to 65% carbon dioxide and air.
Whole beans were treated for 24 and 48 hours at 24, 37, and 50°C., rolled flat in a roll mill and expressed at 45-60°C. in a Carver hydraulic press at 10,000 lb. per sq. inch.
From each sample of beans pressed was taken two samples of oil. One sample was left exposed to the air while the other one was sealed by means of a cap.
From the taste and odor tests it was found that whole beans treated with ethylene at 24°C. Gave the best oil, being only slightly better than the oil from the whole beans treated at 37°C.
Soybeans, when treated with ethylene and carbon dioxide, absorb varying amounts of the gases, depending on the gas concentration and the water removed.
The drying rate of the soybeans by air was considerably less than the drying rate when ethylene and carbon dioxide were used.