The effect of drying conditions on the stability of ascorbic acid and total polyphenolic compound in galanga / Norazua Mohd Norrizan

Moisture content by the dried galanga sam le was between 10% to 10.5% at 50 C and 70°C. Ascorbic acid content in fresh galanga was 12.64 mg/lOOg. Oven drying of galanga at 50°C and 70°C incun-ed loss of ascorbic acid content. The losses of ascorbic acid in dried galanga treated with 300 m (10.78 mg/lOOg) and 600 m (11.46 mg/lOOg) and dried at 50°C were 14% and 9.3 % while for ascorbic acid in dried galanga treated with 300 m (8.98 mg/lOOg) and 600 m (9.20 mg/lOOg) and dried at 70°C were 28% and 27 %. In general, ascorbic acid content was affected by drying tem erature. Higher retention of ascorbic acid was observed using lower drying tem erature 50°C com ared to 70°C. Ascorbic acid losses in untreated dried galanga at drying tem erature of 50°C (8.46 mg/lOOg) and 70°C (6.08 mg/lOOg) were higher (33.1% and 51.9%) com ared to treated sam le. oly henolic content in fresh galanga was 61.02 mg/lOOg. Dried galanga treated with 300 m (37.10 mg/lOOg) and 600 m (45.98 mg/lOOg) sodium metabisul hite and subjected to drying at 70°C, incurred higher losses of oly henolic content of 39% and 24.6% were observed. In com arison, using 50°C drying tem erature incurred lower losses of oly henolic content which were 28% and 21% for dried galanga treated with 300 m (43.90 mg/lOOg) and 600 m (48.28 mg/lOOg) sodium metabisul hite. oly henolic losses in untreated dried galanga at drying tem erature 50°C (30.99 mg/lOOg) and 70°C (21.11 mg/lOOg) were 49.2% and 65.4% which were higher than treated sam le at the same tem erature (50°C and 70°C). From the colour measurement higher L (56.13) and b values (17.45) for sam le treated with 600 m sodium metabisul hite at 50°C. There is significant difference ( <0.05) sam le treated with 600 m sodium metabisul hite in L and b values with sam le treated with 300 m sodium metabisul hite and untreated sam le.