Enzymatic Milling of Corn: Optimization of Soaking,Grinding, and Enzyme Incubation Steps |
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| Authors: | David B Johnston Vijay Singh |
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| Abstract: | Enzymatic milling is a modified wet‐milling process that uses proteases to significantly reduce the total processing time during corn wet milling and eliminates the need for sulfur dioxide as a processing agent. To optimize the overall enzymatic milling procedure and minimize the amount of enzyme, a series of experiments were done to determine the best first grind parameters and the optimal enzyme additions. The yields for germ, germ quality, and starch recovery were used for evaluation of first grind and enzyme addition, respectively. The specific processing conditions evaluated were the soaking time and first grind parameters. After soaking and first grind optimization, enzyme concentration and pH determinations were evaluated using bromelain as an example. The first grind procedure was optimized by evaluating a combination of different soaking and grinding conditions followed by a fixed enzyme addition and incubation step. The pH profile of bromelain for enzymatic milling was evaluated for pH 3.5–6.5 and the optimum was determined to be pH 5.0. Enzyme addition was then evaluated using the optimized first grind conditions and bromelain additions with 0–1.9 g of enzyme (based on protein)/kg of corn. Results showed that the minimum addition of bromelain to reach starch yields equivalent to conventional yields were ≈0.4 g of protein/kg of corn. This amount is significantly less than what was previously used and reported. |
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