Raisins are food made from fresh grapes. High-quality raisins are full and elastic in shape and have a glutinous and sweet taste. High-quality raisins are not crystallized or sour.

During the drying process of grapes, the optimum temperature for the conversion of sugar into monosaccharides in grapes is 55-60 degrees. The processing of raisins includes natural drying and heat pump air drying. Natural drying takes a long time, and the temperature cannot be controlled and cannot be satisfied. In large-scale production needs, the air energy heat pump grape dryer can accurately control the drying temperature and humidity during the drying process, which can achieve zero pollution, low operating cost, and high efficiency. It is an indispensable machine for modern production.

Choose seedless grapes with bright color, thin skin and thick flesh, suitable maturity, and sugar content of more than 20%. Wash them and put them in the dryer tray. Put the tray on the drying rack and push it into the drying room.

1. The initial temperature is between 40-50 degrees Celsius, and 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 drop is controlled at 55 degrees Celsius, and the baking time is 5 hours. At this time, the moisture content of the grapes is less than 12%.

At this time, the raisins do not change color, the flesh is soft, the raisins are dry in the hand, and no juice oozes out. After pinching them tightly, release them, and the particles quickly spread out and the dryness is suitable. The taste is neither sour nor astringent, waxy, and sweet. The surface of the white raisins is slightly frosted, and the color is crystal green and transparent after removing the frosting. The red raisins are frosted on the outside, translucent, and purple-red when the frosting is removed. The moisture content is less than 15%.

The water content of grapes is relatively large. Usually, 1 catties of raisins can be obtained after drying every 4 catties of grapes, and the dehydration rate is about 70%. Because the skin of the grapefruit is very easy to damage, it is necessary to be careful when loading the plate, and not squeeze too much.

The host is an intelligent integrated device controlled by PLC. After pushing the grapes to be dried into the drying room, touch the host panel to set the grape drying temperature, humidity requirements, continuous drying time, moisture removal mode, and other parameters. , click on the control panel to start the host, after 18 hours of the continuous drying operation, the host automatically