Desulphiting dried apricots by exposure to hot air flow

Sulphited dried apricots were exposed to hot air flows at 40, 50 and 60 °C and the removal of SO2 was investigated as their moisture content fell from an initial value of 193.2 g kg−1 to a final value of 80–90 g kg−1. A first-order kinetic model was found for the removal of SO2 between 40 and 60 °C. Temperature quotients (Q10) for the removal of SO2 were 2.84 between 40 and 50 °C and 4.93 between 50 and 60 °C; the activation energy (Ea) was 114.40 kJ mol−1 between 40 and 60 °C. Analysis of the kinetic data also suggested a first-order reaction for non-enzymatic browning, with Q10 values of 2.34 between 40 and 50 °C and 5.36 between 50 and 60 °C and an Ea value of 109.36 kJ mol−1 between 40 and 60 °C. Exposure of dried apricots to a 60 °C air flow resulted in a rate constant for brown pigment formation that was 12 and 5 times higher than those at 40 and 50 °C respectively.