Studies on Extraction of Soybeans by Liquid Butane. IV.

Abstract

Soybean proteins are liable to undergo denaturation by heating. Particularly, when the moisture content of soybeans is high, protein denaturation takes place readily even at relatively low temperature levels. Even in the case of butane extraction, the occurrence of protein denaturation is conceivable when extracted flakes from soybeans of a high moisture content is subjected to a local overheating in the commercial desolventizer. Extracted flakes from raw soybeans without preliminary drying also have invariably too high moisture content to be accepted normally in the market. It is therefore necessary to reduce the moisture content of soybean flakes by drying without causing any denaturation of their proteins.In this paper, results of studies on drying soybean flakes using a through circulation dryer were reported. This dryer operated under the optimum condition has been found very effective, giving dried flakes of a moisture content of about 8% or less. The decrease of soluble proteins during drying is only 1% or less (on the basis of total proteins). Also the data on the design of a 200 tons per day dryer are presented.