| Abstrakt: |
Simple solar dryers with rotary chimney (SDR) and of tunnel type (SDT) with transparent polyethylene cover and black polyethylene cover (SDT-B) were tested in dehydrating tomato, onion, cabbage and spinach. Solar dryer temperatures increased by 5-15°C relative to that in open sun-drying. Tomatoes, onions, cabbage and spinach dried in 47, 44, 27 and 24 hours in SDR, respectively, and 51, 48, 31 and 28 hours in SDT, respectively, or 20-44 hours earlier than sun-drying. SDT-B took a longer time to dry cabbage and spinach than other solar dryers. Solar-dried onion and cabbage had high rehydration ratio. Colour (L*, a* and b*) of dried products was not affected except for SDT-B that maintained the green colour of spinach. However, vitamin C content as nutritional indicator decreased in the dried products. Future studies could look into techniques to minimise nutritional loss during solar drying of vegetables. |
