Effect of drying conditions on the quality of pears

Drying is one of the most common processes used in food preservation. In this study, the effects of the different temperature (60-70-80 ºC) and air velocities (0.8-1.6 m / s) on the quality Deveci pear were investigated. The drying process was carried out in a laboratory scale cabinet dryer. Dry matter, water activity, pH and color values (L *, a *, b *) were determined in fresh and dried pears. Kinetic data with respect to moisture ratio vs time were collected. Besides, sensory analysis and rehydration capacity analyzes were performed in dried pears. When the effects of drynig temperature (60-70-80 ºC) and air velocities (0.8-1.6 m / s) were investigated; the water activity values (aw) were found 0,998 and for the fresh pear samples and were found 0,370-0,254-0,123 in terms of increasing drying tmeperatures (60-70-80 ºC), respectively. It was found that the decrease in moisture ratio was slower at low temperature and lower air velocity. In terms of color, the L * (brightness) value decreased with the increase in temperature values. The + a * (redness) and + b * (yellowness) values increase with increasing temperature and air velocity. Rehydration was performed at two temperatures, 35-55 ºC. As a result of these processes, as the temperature at which rehydration increases, the time to reach the saturation point of water holding capacity is decreased. As a result of rehydration process, the sample which has the best water retention capacity in plain and ascorbic acid treated pears was found to be the sample dried at 70 ºC and 1,6 m / s air speed. The sample that recovered the lost water at the highest rate (83.45%) was the sample which was treated with ascorbic acid; rehydrated at 35 ºC and dried at 70 ºC temperature 1,6 m / s air speed. According to the sensory evaluations, the most appreciated pears in terms of color and taste were the samples which were dried at low temperature and high air velocity (60 ºC 1.6 m / s). In terms of texture, high temperature and high air velocity (80 ºC 1.6 m / s) dry samples had the highest scores. 18.