Modelling of Starch Gelatinisation and Liquefaction with the Enzyme Liquozyme

Abstract

In this paper the influence of the enzyme Liquozyme Supra concentration (0.4-1.2 kg/t dry substance DS) and gelatinisation time (3-11 min.) on the liquefied starch quality is investigated. The composition in sugars with different Degrees of Polymerisation (DP) as DP1 (glucose), DP2 (maltose), DP3 (maltotriose), DP4 (maltotetrose) and oligosaccharides with DP≥5 is analysed by using HPLC with RI detector. The products obtained have different DP, the main components being oligosaccharides with DP≥5, followed by small amount of DP3+DP4 and much smaller concentrations of DP1; no DP2 is produced by this enzyme. Two quality criteria: the percent of oligosaccharides with DP≥5 and the percent of DP1 are proposed, in order to appreciate gelatinisation + liquefaction for the obtaining of various syrups in the next step of starch hydrolysis, the saccharification. For the production of maltose syrups, the optimal conditions at gelatinisation + liquefaction in the domains tested are 0.4 Kg/t DS enzyme and 11 min. gelatinisation time; no conditions are imposed for the production of glucose syrups; at the obtaining of dextrose syrups, gelatinisation and liquefaction are to be realised with maximal enzyme concentration (1.2 kg/t DS) and maximal gelatinisation time (11 min.).