FOOD. Science. Technology. Quality

Food. SCIENCE. Technology. Quality

Food. Science. TECHNOLOGY. Quality

Food. Science. Technology. QUALITY




The influence of stabilising addivives on the thermal inactivation kinetics of Aspergillus oryzae α-amylase


The aim of this study was to investigate the thermal stability of Aspergillus oryzae α-amylase in presence of different sugars (sucrose and trehalose) and polyols (mannitol, sorbitol, lactitol and glycerol). Additional hypothesis was tested – if it is possible to estimate the heat stability of the enzyme based on the amount of hydroxyl (OH) groups provided in a buffer solution (by different compounds). Additives used in all concentrations caused the extension of the decimal reduction time of enzyme activity at 68°C and shows its stabilizing treatment on enzyme. The differences of effectiveness of stabilization were observed on dependence of the type of substance and its concentration. The usage of saccharides was more profitable than usage of multi hydroxyl alcohol, but the most effective additive was sucrose. Stabilizing compounds can be classified, in terms of their protective effect on α-amylase heat stability, as follows: mannitol < lactitol < sorbitol < glycerol < trehalose < sucrose, sugars being more favorable than polyols. Among all stabilising compounds investigated, sucrose exhibited the largest protective effect. The number of hydroxyl groups per molecule and the total amount of hydroxyl groups provided by additives to the system were not correlated with the heat stability of Aspergillus oryzae α-amylase. The source of OH groups was found to be more important, sugars (especially sucrose) being more effective than polyols for similar number of OH groups.


thermal inactivation, protective additives, mannitol, lactitol,, sorbitol, glycerol, trehalose, sucrose