Evaluation of Effective Parameters on Enzymatic Hydrolysis at Low Starch Concentrations

Enzymatic hydrolysis of starch is one of the most important enzymatic technologies nowadays, leading to important amounts of sweeteners in food industry. It is accomplished at industrial scale using high starch concentrations; the present study deals with a less explored pathway, the one of low starch concentrations, originating from the residual starch in waste waters. The effective parameters of enzymatic starch hydrolysis were studied at laboratory scale, using a commercial enzymatic product (Dextrozyme® GA); experiments were carried out using low concentration starch systems, which were hydrolyzed monitoring the influence of pH, temperature, starch concentration and mixing rate on the reaction rate. Enzymatic reactions were monitored using high performance liquid chromatography, with a system enabling the quantification of glucose, fructose, saccharose and maltose. A complete factorial design at two levels was applied, the measured system’s response being the reaction rate. The obtained data demonstrated that the most important effect on saccharification is due to the pH, this being followed by starch concentration, temperature and mixing rate. Temperature, starch concentration and mixing rate are positively related with the reaction rate, while pH is inversely related with this. Analysis on the parameters’ interactions revealed that the most important interaction is the one between temperature and pH, followed by concentration-temperature and concentration-pH, while the combined interaction concentration-temperature-pH-mixing rate can be considered negligible