Abstract:

In order to improve corn wet-milling, L-cysteine was used to replace SO2 in traditional steeping process for
reducing the pollution of SO2. L-Cysteine was added to a sour liquid, corn juice fermented by Lactobacillus paracasei
subsp. paracasei L1. Crushed corn samples were steeped in the steeping liquid and milled with water after a certain time
of steeping and sieved to remove impurities such as fiber. Starch was sedimented quickly under the action of Lactobacillus
paracasei subsp. paracasei L1 which has high flocculating activity. The effects of various factors on the increment of
soluble protein in steeping liquid and starch extraction yield were studied by changing the amounts of fermented corn juice
and L-cysteine, steeping time, steeping temperature, pH and inoculum size. The optimum conditions for corn wet-milling
were determined by response surface methodology as follows: a ratio of solid to liquid (fermented corn juice) of 1:4 (m/V),
an L-cysteine concentration of 1.5 g/100 mL, pH 7, a steeping temperature of 30 ℃, and a steeping duration of 48 h. Under
these conditions, the maximum extraction yield of starch was 93.21%.