Studies of vegetable drying process in infrared film dryer
Latvia University of Agriculture, Institute of Agricultural Machinery, Cakstes blvd.5, Jelgava, LV – 3001, Latvia
The research work analyzes the two fresh vegetable (carrot and garlic slices) drying process in the infrared film dryer. The energy of infrared radiation penetrates through the material and is converted into heat, and the temperature gradient within the product is reduced in a short period of time. Infrared drying takes place at low temperatures (up to 35 °C) and it helps keep the maximum product quality and natural color. The vegetable drying rate significantly differs depending on the location of the products in relation to the infrared film and product location at the air inlet and outlet. With dried products in 3 parallel shelves the most rapid removal of moisture occurs in the lower shelf (close to the air inlet and film) and the top shelf (close to the air outlet and film). This difference compared to the middle shelf reaches 10–15%. Using the experimental data and multivariate analysis it has been found that the product moisture removal depends on its placement (at the heating film and air inlet, outlet) and the drying time.