Effect of drier type, cultivar, product and water temperature on major components and rehydration ratio of dried potato products

Potato is one of the most important agricultural crops and there is remarkable loss of this produce because of unfavorable storage conditions. Therefore, it is vital to convert raw potatoes into some processed products such as dried ones. Our aim was to evaluate three cultivated potatoes of Golestan province of Iran (so-called Agria, Satina and Kenebek) to find the best cultivar for dehydration. Also, we investigated the influence of drier type (Microwave oven and Hot air oven) and shelf life on the rehydration behavior of processed potatoes (powder and cubes). Total sugars, reducing sugars and ascorbic acid contents were analysed to evaluate the processing effect on product components. The factorial completely randomized design was selected as the statistical design and three replications were conducted for each treatment. In order to examine the quality and shelf life of products during storage, the analyses were continued until three months. Results revealed that there is significant difference (P<0.05) between microwave processed potatoes and hot air ones, due to different heat transfer mechanisms. For instance, ascorbic acid content in the former products was about 8.3 mg/ 100gr dry matter which was significantly (P<0.05) higher than hot air dried potatoes. Also water absorption of the cubes which were dried in microwave oven, was about 12% more than hot air ones. It was concluded that all the three cultivars were suitable for producing dehydrated products. Agria had the lowest amount of reducing sugars and the best color accepted by the panelists and Kenebek had the highest rehydration ratio but from from theoveral point of acceptability, Satina received the highest score amongst three cultivars.