INFLUENCE OF DRYING CONDITIONS ON THE HAZELNUT QUALITY .3. BROWNING

The influence of drying conditions on browning in hazelnut (Corylus av ellana L.) has been studied by means of color measurement. Samples of unshelled and shelled hazelnuts were dried under six air temperatures (30, 40, 50, 60, 70 and 80 degrees C). The drying experiments were don e with forced air circulation, and two varieties of hazelnut were inve stigated, Negret and Pauetet. CIELab system was used to evaluate chang es in total color (Delta E), lightness (L*), chroma (C*) and hue angl e (H) on dried hazelnuts. Browning of hazelnut was observed to occur at all temperatures studied. The rate of pigment formation was determi ned from the Delta E values with zero-order kinetic model, and temper ature dependence was described by the Arrhenius equation with an activ ation energy (E-a) varying from 28 to 39 kJ/mol. Negret variety showed the highest rate of browning.