S.Aruna, Dr. A. Nishadh
The effect of thermal processing on pink coloured radish were determined using antray and freeze dryer at different temperatures (600C, 700C and 800C) and (-400C, -500C,-600C). The ascorbic acid content, polyphenol content and anthocyanin content were also measured from the fresh and dried radish. Thick slices (5mm) were made for tray dryer and thin slices (3mm) were made for freeze dryer. The moisture content (MC) decreased with drying temperature for both the thick and thin slices in each dryer. The retention of nutrient content was found decreased in the samples dried at higher temperature. The nutrient loss can be reduced by selection of proper temperature for drying. The antioxidant constituents in dried radish were decreased with higher temperature as compared with fresh sample. There was nohuge change on the ascorbic acid, polyphenol and anthocyanin contents of dried radish when dried at (600C ) in tray dryer and (- 500C) in freeze dryer. But there was about slight decrease in the ascorbic acid, polyphenol and anthocyanin content in radish after drying at different temperatures.