Abstract
An enzymatic corn wet milling process has been developed that replaces or reduces the use of sulfur dioxide (SO2) by using proteolytic enzymes. An acid fungal protease (GC106) was evaluated in this process, and its dose was optimized for starch yield using a laboratory enzymatic wet milling procedure. Starch yields from enzymatic wet milling treatments were compared to a conventional control treatment using 2 000 ppm SO2. To reduce enzyme dose, a treatment with a low level of SO2 (600 ppm), along with enzyme, was evaluated and compared to the control treatment. Starch yields increased from 58.7% to 70.9%, with an increase in GC106 dose from 0 to 10 mL. Enzymatic wet milling treatment with 1 mL of GC106 and a reduced amount of SO2 (600 ppm) resulted in a starch yield similar to that of the conventional control.
A commercial trial of the enzymatic wet milling process was conducted in a 200 tonne/day corn wet milling plant in Prai, Malaysia. Depending upon the amount of enzyme and SO2 used, a 2.1% to 4.6% increase in starch yields was observed for the enzymatic process as compared to the conventional process during the trial.