Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 1/22/2009
Publication Date: 5/10/2009
Citation: Eggleston, G., Montes, B. 2009. Optimization of Amylase Applications in Raw Sugar Manufacture that Directly Concern Refiners (abstract). Sugar Industry Technologists. (973):243-252.
Technical Abstract: In recent years there have been warnings by some U.S. refineries that there may be a penalty for high starch concentrations in raw sugar if starch control is not improved. Most commercial alpha-amylases used by the U.S. sugar industry to control starch have intermediate temperature stability (up to 85 degrees C with an optimum ~70 degrees C), and are produced from Bacillus subtilis. A method incorporating PhadebusTM blue starch tablets was modified to simulate conditions in typical last evaporators, i.e., pH 6.4 and 65.5 degrees C, where alpha-amylases are mostly currently applied. A wide range of activity existed for alpha-amylases (59.0 to 545.3 KNU/ml) that did not reflect their comparative unit costs, i.e., activity per U.S. dollar only differed 4-fold from 40.7 to 161.8 KNU/ml/$. Concern about the use of engineered high temperature stability (up to 115 degrees C) alpha-amylases from Bacillus licheniformis and stearothermophilus, developed for much larger markets than the sugar industry, and possible carry-over activity into raw and refined sugars, molasses, and food products are discussed. Customers of U.S. refineries have requested that no amylases are added in the refinery process and U.S. refinery staff have requested raw sugar factories not to add high temperature stable alpha-amylases at the factory. Optimization of the application of intermediate temperature alpha-amylases to the next-to-the-last evaporator in factories increases starch break down.