Effect of shelf life on quality changes of potato dried powder and cubes to select the best usage duration and variety

Drying of foods is one of the most important preserving methods due to reduction of microorganisms’ activities which lead to longer shelf life. In spite of this، some changes may occur in dried food during storage. Our goal was to evaluate effect of pretreatment (blanching)، variety and shelf life on quality of potato dried products (powder and cubes) to select proper usage duration and variety. Three cultivated potatoes of Golestan province of Iran (so-called Agria، Satina and Kenebek) were dried in two different dryer (hot air oven and microwave oven). Changes during shelf life were investigated by measuring ascorbic acid and reducing sugars content plus rehydration ratio (in 100ºC and 25). The factorial complete randomized design was selected as the statistical design. Results revealed that there was significant difference (p<0. 05) between cubes and powders amount of components. Also water absorption of the products and ascorbic acid content، showed a significant (p<0. 05) reduction during three months storage، so it was concluded that it was better to use dried products before this time. Also، products which were dried in hot air oven، had the highest percent of water absorption in 25 ºC water in the first month of storage but after three months، it was changed to 100 ºC water. But the products which were dried in microwave oven had the highest percent of water absorption in 100 ºC during alls storage time. At last، Agria، because of its brilliant yellow color and low amount of reducing sugars، was the most accepted variety and proper usage duration was before three months storage.