Effect of drying methods on quality of Indian gooseberry (<i>Emblica officinalis </i>Gaertn.) powder during storage

Abstract

Indian gooseberry or aonla is a very rich source of ascorbic acid. Its ascorbic acid lost during the process of drying. Therefore effect of 4 different drying methods investigated on ascorbic acid and other quality factors under storage. Drying methods <i>viz</i>., sun drying, oven drying, microwave drying and fluidized bed drying, significantly affect the quality and ascorbic acid content of dried aonla powder. Among 4 drying methods, fluidized bed drying found best. At the start of experiment dried powder with fluidized bed drying had highest ascorbic acid content (272.74 mg / 100 g), total sugars (39.41 g / 100g), reducing sugar (33.69 g / 100g), and lowest content of tannin (8.8 g / 100g), browning index (0.02 OD at 440 nm) and acidity (9.94 g / 100g). The quality parameters

deteriorated under storage irrespective of the drying method and ascorbic acid steadily lost during 90 days of storage. However, powder making with fluidized bed drying was acceptable even after 90 days of storage and contains 205.5 mg / 100g ascorbic acid. It is recommended that aonla can be dried with fluidized bed drying at a temperature of 65^oC with air velocity of 90 m/min.