Abstract
A laboratory investigation of corn steeping was performed using several kinds of agents (sodium hydrogen sulfite, sodium thiosulfate, sodium hydrosulfite, sodium carbonate, sulfurous acid, sodium hydroxide and sulphuric acid). 1) No difference between steeping at 30°C and 50°C was found in the water absorption during the steeping and in the yield of starch, but the extraction of protein was increased at 50°C as compared with that at 30°C. On steeping at 50°C, the extraction of protein was in the following order: 0.4% sodium hydrogen sulfite > 0.4 % sulfurous acid >0.2 % sulphuric acid > 0.1 % sodium hydroxide. The yield of starch increased in steeping using sodium hydrogen sulfite and sulfurous acid in comparison with sulphuric acid and sodium hydroxide. 2) The protein contents of starches after steeped at 30°C in sodium hydrogen sulfite and sulfurous acid were 0.40.46/0, but those in sodium hydroxide and sulphuric acid were 0.74-0.84%. 3) The temperatures of gelatinization of starches after steeped at 50°C in 0.2% and 0.4%; sodium hydrogen sulfite were lower than the others, and their maximum viscosities were highest in those starches.
