Effect of anti browning agents and slice thickness on drying and quality of apple slices var. Red Chief

Apples of Red Chief variety after stabilization at room temperature (20±2 °C) were initially washed with chlorinated water (100 ppm sodium hypochlorite) to prevent surface contamination. After manual peeling, apples were cut in to disc shaped slices of 2 and 3 mm thickness (having uniform diameter of 20 mm) and treated with 1% ascorbic acid and 1% citric acid (anti browning agents) for studying their effect on drying time and quality of apple slices. Slice size and pre-drying treatments of ascorbic acid and citric acid has resulted in significant (P<0.05) variation for drying time, rehydration, dry matter contents, firmness, quality and total colour change. Significantly minimum time (300 minutes) for drying of apple slices, maximum rehydration ratio (4.9), and maximum firmness (11.9 RI) was recorded in case of 2 mm slices treated with 1% ascorbic acid and 1% citric acid. Maximum TSS (18.9° Brix) was recorded in 2 mm slices and 3 mm slices (18.7° Brix) treated with citric acid and ascorbic acid. Ascorbic acid and citric acid were effective to stabilize the ascorbic acid content and maximum (18.0 mg/100g) was recorded in case of slices of 2 mm thickness treated with 1 % ascorbic acid and 1% citric acid. Similarly size of slices and anti browning agents were significantly effective to reduce the total colour change in apple slices and minimum colour change was observed in 2 mm slices (10.0) treated with 1 % ascorbic acid and citric acid and 3 mm slices (12.25) treated with 1% ascorbic acid and 1% citric acid. It can be concluded that apple slices of 2 mm thickness and pre drying treated with 1% citric acid and 1% ascorbic acid as anti browning agents took minimum time for dehydration with minimum changes in colour, firmness, quality, and retained maximum compositional attributes with minimum browning.