The introduction of red dates
As a well know traditional healthy food, red dates contain plenty of nutrients. Most of them are dried up and are directly eaten by consumers as dried cleaning-free fruit. In addition, the growing areas of red dates are relatively centralized, and most fresh red dates are harvested in autumn almost at the same time and serve the whole market.
How to dry jujube?
The core of red dates processing is drying. The drying process is composed of evaporation of water and sugar conversion on the premise of maintaining the original quality of jujube as far as possible. For the sake of storage, transport, selling, the fresh red dates have to be cleaned, dried, cooled, softened, sterilized, packed.
Red dates abound in sugars. Among them, the polysaccharide is not sweet and only becomes sweet after inverted into simple sugars by the function of the biological enzymes. It is the reason why cured jujube is sweet. If we want to invert sugars fully, we need to strengthen the activity of the biological enzymes. After a long time of practice in our drying oven, we have found the most suitable temperature for completely sugar conversion is about 60°C.
Drying process of red dates
In the process of drying red dates, there are many details that need to be clear. Generally speaking, the drying process is divided into four steps, preheating, evaporation, drying, cooling. The following is about some precautions and process introduction during the drying process.
Preheating: If we directly put red dates in the environment where the temperature is suitable for sugar conversion, the extreme temperature difference will make red dates set off the protective reaction. The cell orifice in the skin will shrink and the crust will become hard to prevent water from evaporating. Therefore, sufficient preheating is required in the early drying to prepare for the evaporation. First, the red dates need to be dried at 35°C for 6-10 hours. When the temperature of red dates reaches 45°C, your finger will feel hot when touching it. After drying them for 7-8 hours, use your finger to press the red date and wrinkles will appear on the surface. When the temperature is at 45°C-48°C, there will be some small water drops on their skin.
Evaporation: Raise the temperature to 65°C (Note: the temperature shall not be higher than 70°C) within 8-12 hours to evaporate most of the free water. Keep the indoor temperature stable for constant evaporation. The drying process goes well when the wrinkles appear on the surface.
Drying up: When the temperature in the red date is uniform, this step will end within 6 hours. In this phase, the moisture content of red dates is not high, and thus more attention shall be paid to temperature control. It is best to keep the temperature at 50°C. At this moment, relative humanity has been declined. As the water in the red dates is gradually balanced, the drying process is completed. Note that the dried red dates shall be taken out in time.
Cooling: Keep good ventilation and heat dissipation for dried red dates. Pile them up until being cooled. If the dried red dates are just taken out from the cabinet, and directly piled up in the warehouse, their sugars will ferment and go bad, and the pectose will be broken down into pectin and pectic acid due to high heat. Therefore, it is necessary to wait for the completely cold zone before piling up.
The benefits of dried jujube
- Delicious flavor food
- Rich in a variety of vitamins
- Contains nutrients such as calcium, phosphorus and iron, which is conducive to promoting bone growth
- Nourish the spleen, nourish qi and nourish blood