Determination of rehydration amounts and texture properties of dried squash (Cucurbita pepo) at different temperatures and agitator speeds

In this research, squash (Cucurbita pepo) fruits were cut into 0.4 cm thick and 4 cm diameter slices. After blanching, squash slices were dehydrated in a hot air dryer, under air temperature of 60±0.5°C until moisture content of 0.1065 kgw/ kgdm Dehydrated samples were stored at 4°C until their use in the rehydration process. Squash slices with specified weight were rehydrated by immersion in distilled water at different temperatures (25, 50, and 75°C), which was agitated at different speeds (0,100, and 200 rpm). For all experiments, solid to water ratio was kept at 1:25. At specified time intervals, namely, 1, 3, 5, 10, 20, 40, 60, 120, 180, and 300 min the squash sample was removed from the water, and the weight, moisture content and rehydration indices of the sample were determined. The texture characteristics were examined over a 180 min period. The results showed that moisture content, WAC and RA of squash slices increased, whereas DHC and texture firmness decreased with rehydration time. In general, for all rehydration conditions of squash slices, the highest water absorption rate occurred during the first minuts of process, then this rate decreased. The maximum of moisture content, WAC and RA and the minimum of DHC, force and stress, were observed in squash slices rehydrated into 75°C water which was agitated at 200 rpm.