Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 4/1/2004
Publication Date: 4/10/2004
Citation: Johnston, D., Singh, V. Starch production from an enzymatic maize wet milling process: enzyme and process optimization. Meeting Abstract.55th Annual Starch Conference, Detmold Germany, April 20-24, 2004. Paper #3.1.
Technical Abstract: Enzymatic milling (E-Milling) is a modified wet milling process for the fractionation of maize. The E-Milling process incorporates proteases to significantly reduce the total processing time during maize wet milling and eliminates the need for sulfur dioxide as a processing agent. To optimize the overall E-Milling procedure and minimize the amount of enzyme required, a series of experiments were done to determine the best first grind parameters and the optimal enzyme addition. 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 (speed and time). Following the 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 from pH 3.5 to 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 loading varied from 0 to 1.9 g enzyme (based on protein) per kg of maize. Results showed that by using the optimized milling conditions, the minimum addition of bromelain to reach starch yields equivalent to conventional yields was approximately 0.4 g protein per kg of maize. This amount is significantly less (5 fold reduction) than what was previously used and reported. In addition to results for the processing optimization, a comparison of coproduct composition and pasting properties will be presented.