Honey diastase activity modified by heating

Abstract

Diastase activity is a honey quality parameter used to determine if honey has been extensively heated during processing. Honey heating effect on the diastase activity was studied in two steps. Heating was carried out in the transient heating step, with final temperatures between 60 and 100 °C and 14 s elapsed time, and in the isothermal heating step, in which temperature was held between 60 and 100 °C at heating times between 120 to 1200 s. Six honey samples with initial diastase activity between 25.8 and 11.2 Schade units were tested. During the transient heating, it was observed a decrease in the diastase activity related to an increase in temperature in all assays. The activity becomes zero at 100 °C for both transient and isothermal heating. During isothermal heating, all samples showed a decrease of the diastase activity at short heating times. However, an activity recovery occurs in medium temperature treatments at longer times. The initial activity value, corresponding to the control sample, was not achieved in any case. This changing behaviour makes diastase activity an uncertain parameter to determine if honey has been submitted to heating.