Delicious persimmon is a food that we all love to eat. How are delicious persimmons dried? Today, the supplier of the heat pump drying project will take you to understand the drying of persimmons!
The traditional dried persimmons drying process is complex and the drying cycle is long, causing serious microbial contamination. Today I want to share with you the heat pump drying of dried persimmons!
Persimmons contain a lot of water, tannin, protopectin and other substances. Fresh persimmons are crisp, hard, juicy and have an astringent taste. To make soft and sweet persimmons, four changes must be completed!
(1) The tannin changes from soluble to insoluble, so that the persimmon has no astringency;
(2) The original pectin is changed into pectin to make the dried persimmon soft;
(3) The water evaporates to concentrate the contents;
(4) The sugar inside the fruit penetrates outside and condenses into persimmon frost. Artificially baked persimmons are cleaner and more hygienic than natural sun-dried persimmons, and are not affected by weather changes. Here is a brief introduction to the operation points of the artificial drying technology of dried persimmons for your reference:
1. Fruit selection. Select fully mature and timely harvested fruits of excellent cake-making varieties as raw materials, remove diseased and insect fruits and soft fruits, and stack them separately according to size and maturity.
2. Peel the skin. Before peeling the same type of fruit, remove the sepals, cut off the fruit stalk, clean the dust on the pedicle, and use a peeler to thinly peel off the peel. Peel off the skin, do not leave the top skin and flower skin, only keep the 0.5cm wide skin around the persimmon pedicle without peeling.
3. Drying. The temperature of the oven during baking affects the drying speed and quality of persimmon fruit. The variable temperature interval baking should be carried out according to low → high → low. That is, the initial furnace temperature is controlled at about 40°C. After the fruit is deastringent and softened, the furnace temperature is raised to about 50°C, so that the water evaporates rapidly, the fruit loses water to 50%, and the temperature is lowered to 40°C until it is baked. The standard of baked persimmons is that the inside and outside are soft and hard, the flesh is full of elasticity, and the water loss rate is 65%-70%. The furnace temperature in the early stage should not be too high, otherwise the activity of alcohol dehydrogenase will be inhibited, soluble tannins will not precipitate, and the baked persimmons will still have an astringent taste; During the whole roasting process, the temperature should not be lower than 30°C, otherwise it is easy to grow mold or ferment; and it should not exceed 70°C, otherwise the persimmon fruit will be steamed and turn yellowish brown, with jelly exuding from the fruit surface, and the flavor will be bad.
The drying process should also pay attention to ventilation, and the furnace must be well ventilated. When the ventilation is poor, the moisture in the furnace cannot be discharged, and it is easy to mold and ferment. Although the furnace temperature will be lowered after ventilation, low temperature ventilation is better than high temperature airtight.
4. Turn over. Due to the uneven temperature in the drying room and the different speed of water evaporation, it is necessary to change the position of the baking sieve every certain period of time to make each plate dry evenly and be baked in the same batch. In order to improve the utilization rate of the oven and improve the quality of dried persimmons, it can be baked in two or three batches in rotation.
5. Mildew proof. Penicillium, Rhizopus, Mucor and Aspergillus cause mold on persimmons. Persimmons are prone to mold in high temperature and high humidity, so be careful. In addition to clean and hygienic utensils, the fruit arrangement should be loose when baking, and pay attention to turning over, because the water vapor is not easy to escape from the place where the fruit is attached or in contact with the baking sieve, and it is easy to mold; combined with kneading to smooth wrinkles, the humidity in the wrinkles is high, It is also prone to mold after a long time.
6. Frost. Put the baked persimmons in a clean container and cover them. After the fruit surface softens, put it in a cool place to let it air out. After the fruit surface is dry, put it in the pile and cover it again. Then dry it every 2-3 days. Repeat this many times to get out early. Frost.