MODELING THE KINETICS OF HYDROXYMETHYLFURFURAL (HMF) FORMATION IN POMEGRANATE SOUR PRODUCED BY DIFFERENT EVAPORATION METHODS

Pomegranate sour is a traditional functional food that is widely consumed in Türkiye. The aim of this study is to determine the most convenient evaporation method to keep the amount of HMF, a carcinogenic substance formed as a result of high temperatures in the production of pomegranate sour, at low levels. The pomegranate sours were produced using five different evaporation methods (atmospheric pressure (AP), freeze-drying (FD), open air (OA), vacuum assisted (VA) and fan assisted (FA)) and the amount of HMF formed during the process was determined. Kinetic calculations showed that VA and FA methods followed first-order reaction kinetics at 60, 70 and 80 °C, while OA, FD and AP methods followed zero-order reaction kinetics at 80, 90 and 100 °C. The mean Q10 value was 1.0006, while the activation energy (Ea) ranged from 72.56 to 126.38 kJ/mol. It was found that the amount of HMF formed varied according to the method, temperature and production time and that the reaction rates increased with increasing temperature, especially for the OA method. In addition, pH, titratable acidity, invert and total sugar content, color, Brix and browning index were analyzed and a kinetic model including all these factors was developed.