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Stability of Bacterial alpha‐Amylase in the Starch Liquefaction Process
Author(s) -
Rosendal P.,
Nielsen B. H.,
Lange N. K.
Publication year - 1979
Publication title -
starch ‐ stärke
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.62
H-Index - 82
eISSN - 1521-379X
pISSN - 0038-9056
DOI - 10.1002/star.19790311104
Subject(s) - bacillus licheniformis , starch , alpha amylase , amylase , hydrolysis , liquefaction , chemistry , enzyme , process (computing) , cellulase , chemical engineering , chromatography , biochemistry , organic chemistry , computer science , engineering , bacteria , biology , bacillus subtilis , genetics , operating system
Nowadays, starch is normally liquefied by an all enzymatic process at a high temperature. In 1973 a new α‐amylase was introduced which was more heat‐stable than the products so far used. It is produced by a strain of Bacillus licheniformis. Since then, this enzyme has been recommended for use in a single dosagejet cooking process, operating at 105 °C for a few min followed by a 90–95 °C dextrinization period. This process is easy and energywise more economic than earlier processes. This lecture deals with the stability of this enzyme, depending on: Temperature, pH, starch dry substance and salt content. A formula for the calculation of stability is given, as a function of these parameters. The degree of hydrolysis, very often measured as Dextrose Equivalent (DE), can for a given process be estimated also by a formula. Results from pilot plant trials confirming the laboratory investigations are presented. Based on the stability data it is possible to estimate optimum design parameters for the use of this enzyme in individual processes, thus minimizing enzyme cost.