Effect of pre-treatment on drying characteristics and colour dehydrated green chillis

Effect of selected pre-treatments on drying characteristics and colour of g reen chilli (Capsicum annuum) was investigated. Blanching was carried out i n hot water at 95 degreesC for 5 min. The pre-treatments were: blanching fo llowed by dipping for 15 min at room temperature in (i) cold water, control , (T1); 1000 ppm sulfur dioxide solution (T2); 1 % lye solution (T3); 1 % l ye solution containing copper sulphate and magnesium sulphate each at 500 p pm (T4); and 1 % lye solution containing 0.25 % magnesium carbonate (T5) re spectively. Pre-treatments resulted in increasing the drying rate, while pr e-treating blanched chillis in 1 % lye solution containing 0.25 % magnesium carbonate (T5) retained maximum colour of the product (in terms of Hunter colour-'a' value). The drying kinetics revealed that for the entire duratio n, drying took place under the failing rate period and Page's model fitted well the drying behaviour of green chilli.