Determination of HMF (Hydroxymethylfurfural) contents of some apple juices on the market by HPLC method

Hydroxymethylfurfural (HMF) were formed when foods that contains sugar stored at improper temperatures or heat treatment applied to high temperature during production. In this research, the conformities of some of the apple juices sold in the Turkish market were estimated according to Food Regulations. For this purpose, 8 different companies essays in markets were collected randomly in order to analysis of pH, hydroxymethylfurfural (HMF) and water soluble dry matter of apple juices. HMF was analysed in the each sample was carried out by using High Performance Liquid Chromatography (HPLC). Result indicated that minimum and maximum values for HMF, pH, water soluble dry matter of apple juices were estimated as 1.77-7.73 mg/L, 2.88-3.83 and 11.3-11.8, respectively. In this study, was also determined the effect of the storage at 15°, 25° and 35°C between 3 and 6 weeks on HMF formation in three different apple juices sold in the market. During storage, HMF content in the apple juices increased by increasing storage time and temperature. HMF concentration at the end of storage time was observed between 4.39-15.89, 1.86-8.24 and 28.55-45.89 mg/L in three different apple juices, respectively. Also, pH and water soluble dry matter analysis were performed on these products. According to kinetic calculations, the formation of HMF in apple juices followed a zero-order kinetic model. Activation energies for three different apple juices were found as 90.92, 153.17 and 62.93 kj/mol, respectively. Q10 values at 15-35°C ranged from 2.06-5.80, 6.06-10.60 and 1.56-3.57, respectively. Keywords: Apple juice, HMF, HPLC, storage, kinetic parameter, activation energy, Q10 value.