Drying of Fruits and Vegetables in a Developed Multimode Drying Unit and Comparison with Commercially Available Systems

A multimode fruits and vegetables drying unit and laboratory dryer were used for drying of different fruits and vegetables, i.e., red onion, Indian gooseberry, papaya, carrot and sweet potato. Drying time, color, antioxidant activity and total phenolic content of the dried fruits and vegetables for vacuum and hot air drying mode were compared for adjudging the performance. The drying time was observed in increasing order as NiftEMA-DU (vacuum drying, i.e., VD), NiftEMA-DU (hot air drying, i.e., HAD), laboratory dryer (HAD) and laboratory dryer (VD). Differences in lightness, redness and yellowness were found a little when compared for both of the drying systems. It was found that differences in retention of antioxidant and total phenolic compound of red onion, Indian gooseberry, papaya and carrot were not high in NiftEMA-DU (VD) and laboratory vacuum dryer. But, in HAD process, retention was higher in all the samples using NiftEMA-DU (HAD). In case of sweet potato, neither dryer type nor drying mode affected the quality properties even though drying time was observed on higher side in laboratory dryers. © 2019, The Institution of Engineers (India).