بررسي اثرات دما و ضخامت محلول بر فرآيند خشك شدن پسته در خشك كن هاي صندوقي

Influence of temperature and thickness on pistachio drying in batch dryers

Batch dryer is one of the most common dryers in Rafsanjan. The temperature and thickness changes have great effects on drying time and pistachio quality. In this study using the randomize complete block design, influence of temperature in two levels (60 and 75°C) and thickness of product layer in two levels (10 and 20cm) on drying time were studied for two varieties of Iranian pistachios as Kalehghouchi and Fandoghi. Using consumer votes, appearance and color changes were studied for two varieties. Also using t-test, changes in flavor of two varieties were evaluated. In addition, drying process was studied for different product layers (each 5cm) in 20cm thickness and results evaluated by using of randomized complete block design. Experiments and statistical analysis showed that the temperature and product thickness have significant effects on drying time in two varieties. Pistachio appearance (color and shape) has no change in the experiments. Different temperatures have significant effects on dried pistachio flavor. The results indicated that at two temperature levels, pattern of moisture content variation in layers was significantly different. Hence use of agitators in dryers with pistachio thickness above 10 cm is advisable. With the consideration of suitable moisture for storage and pistachio quality, enough time recommended to dry each variety.