Raisin is the dried fruit after the grapes are dried. High-quality raisin fructose does not crystallize, does not become sour, and has a waxy and sweet taste. How to produce high-quality raisins in the process of processing dried grapes? The fruits used to make raisins must be mature fruits. The water content in raisins is only 15-25%, and the fructose content is as high as 60%. Therefore, raisins can be stored for a long time. The traditional drying method is to dry in the sun. , the color is not good, the drying is uneven, and the sugar is easy to distribute, what should I do? At present, heat pump dryers are mostly used to dry grapes instead of traditional drying methods.



The Introduction of raisin dryer process:
1. The initial temperature is between 40-50 degrees Celsius, the time is 2 hours, and the epidermal water evaporates.
2. In the mid-term, a large amount of moisture is removed and the temperature is raised to 55 degrees Celsius for 10 hours. At this time, the dehydration rate of the grapes is about 70%.
3. Deep drying, heating up to 60 degrees Celsius, strengthening dehumidification, humidity is 55%, time is 10 hours,
4. The grapes are evenly dehumidified, the temperature cooling is controlled at 55 degrees Celsius, and the baking time is 5 hours. At this time, the moisture content of the grapes is lower than 12%.



The Precautions for raisin dryer:
After drying, the grapes must be ventilated and dissipated, and can be stacked together after cooling. If the raisins that have just been removed from the drying room are stacked in the warehouse, because the grapes themselves contain a lot of sugar, under the action of heat, the sugar is easily fermented and deteriorated, and the protopectin in the raisins will also decompose into pectin and pectic acid. It will inevitably make the grapes a mess, all sticking together, and the sugar in the raisins will change, sour filaments will appear, and the raisins will be damaged. Therefore, after drying, it must be completely cooled before storage. The heat pump dryer can precisely control the drying temperature and humidity in the process of drying raisins, which can achieve zero pollution, low operating cost, high efficiency, and save the cost of manual drying. It is an indispensable machine for modern production.