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United States Department of Agriculture

Agricultural Research Service

Research Project: Postharvest Quality and Processing of Sugarcane and Sweet Sorghum for Sugar and Ethanol Production

Location: Commodity Utilization Research

Title: General Subject 1. Report to ICUMSA on the determination of commercial alpha-amylase activity by a spectrophotometric method

Author
item Eggleston, Gillian

Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: September 24, 2012
Publication Date: September 1, 2013
Citation: Eggleston, G. 2013. General Subject 1. Report to ICUMSA on the determination of commercial alpha-amylase activity by a spectrophotometric method, September 1, 2013, Cambridge, UK. p. 36-44.

Interpretive Summary: The activities or strengths of commercial amylases used at sugarcane factories and refineries could not be directly compared because there was no uniform method used by vendors to measure the activity. A report is given on a new industrial method for the determination of the activity of commercial amylase (an enzyme that is used to break down and control starch in sugarcane factories). The method uses Phadebas® blue starch, which is highly specific for amylase activity. The reactions conditions were chosen to simulate industrial conditions, and single laboratory validation results are described.

Technical Abstract: A report is given on a new industrial method for the determination of the activity or strength of commercial alpha-amylase at a sugarcane factory or refinery, as well as a recommendation. At the present time, the activities or strengths of commercial alpha-amylases cannot be directly compared because there is no uniform method used by vendors to measure the activity. Furthermore, the alpha-amylase market is very dynamic – activities and prices can and do change regularly. This is all further compounded by the world-wide trend of increased amounts of starch being delivered to sugarcane factories which has meant that alpha-amylases are in even greater demand. As a consequence, there was an urgent need for a sugar industry international method to measure the relative activity of commercial alpha-amylases used at the factory or refinery to: (1) directly compare the activities of commercial alpha-amylases, (2) check and monitor the activity of alpha-amylase batches delivered to the factory/refinery, and (3) monitor the change in alpha-amylase activity on storage. A method was developed using Phadebas® blue starch, which is highly specific for alpha-amylase activity and based on reaction conditions in factory last evaporators where most (but not all) alpha-amylases are applied, i.e., 65ºC and pH 6.4. Results from a single laboratory validation study following IUPAC harmonized guidelines are reported. The method is written up in ICUMSA format and attached at the end of the report.

Last Modified: 8/27/2014
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