Application of heat pump dryer in drying walnuts
Overview of walnut drying: Walnuts, which are native to the Near East, are also known as walnuts, citrons, and almonds, cashews, and hazelnuts. They are also called the "four major dried fruits" in the world. It can be eaten raw, fried, or squeezed with oil, prepared pastry, candy, etc., not only delicious, but also has high nutritional value. Its footprint spans almost all parts of the world, mainly in many parts of the Americas, Europe and Asia. In addition to the United States, its output is pushed to China. Walnuts are called "Hercules Food", "nutrient-rich nuts", and "educational fruits" abroad; they enjoy the reputations of "Long live", "Longevity Fruit", and "Treasures of Treasure" in China. Its superior brain-building effect and rich nutritional value have been respected by more and more people. In 1972, the Cishan cultural site was discovered. In the gray pits excavated at the Cishan site, tree seed piles were found at the bottom of the two pits, and hazelnuts, Xiaoyepu and walnuts can be identified. Walnuts are today's walnuts. In the past, walnuts were thought to have been introduced to the mainland when Zhangye of the Han Dynasty passed through the Western Regions. The unearthed walnuts at the Cishan site have confirmed that the area was planted more than 7,000 years ago. The nutritional value of walnuts: 1. Walnuts are rich in unsaturated fatty acids. Frequent consumption of walnuts will not only raise blood sugar, but also reduce the absorption of cholesterol in the intestine. It is suitable for patients with hyperlipidemia, hypertension and coronary heart disease. Walnuts contain A large amount of fat can moisturize the intestines, treat constipation, and make people who lose weight gain weight. 2. As long as the fatty acid in walnut is linoleic acid, it is an essential fatty acid for the human body and an ideal skin cosmetic agent for the human body. 3. Walnuts are rich in vitamin B and vitamin E, which can age cells, have brain health, enhance memory and delay aging. 4. Walnut kernel contains linoleic acid, calcium, phosphorus, and iron. It is an ideal skin cosmetic for the human body. It is often used to moisturize the skin and beard hair, and has the function of preventing premature whitening and hair loss. 5. Walnut kernel also contains a variety of trace elements needed by the human body. It is an important adjunct to proprietary Chinese medicines. When you feel tired, chew some walnut kernels. There is a walnut drying process that is commonly used to reduce fatigue and stress. The walnut drying process is mainly divided into intelligent or semi-only mechanical baking equipment and self-built walnut drying. Craft walnut drying craft walnut baking kiln two categories. The mechanical automatic baking equipment adopts the smokeless baking design; the self-built baking kiln is divided into two types: smoked baking kiln and smokeless baking kiln. No matter what kind of equipment is used for baking, the changes in the baking temperature are: low → high → low. The temperature and time of each stage are roughly as follows: Low temperature ———————— -------------------— High temperature ——————————— —----— Low temperature holding temperature: 35-40 ° C; 40-50 ° C; 30-35 ° C; Baking time: 0-5 hours 5-30 hours 35-50 hours Introduce several kinds of baking walnut baking Dry process walnut drying process: 1. The baking method of the smoke-free self-built baking kiln adopts the heating method of roasting dragon to heat, and each time, about 1.5 tons of fresh stone fruits can be baked. First, check if the grilled dragon has leaked air or smoke. If you find that the leaked air or smoke is leaking, you must deal with it before baking. The peeled walnuts should be promptly put into a kiln (furnace) and stacked on the grill (the pile of stone fruit should not exceed 50 centimeters in thickness), and immediately start a fire. 0 to 5 hours after entering the furnace, the furnace temperature is controlled at 35 ° C to 40 ° C; the furnace temperature is controlled at 40 ° C to 45 ° C at the 5th to 15th hour; the furnace temperature is controlled to 40 ° C to 50 ° C at the 15th to 30th hour; －50 hours furnace temperature is controlled at 30 ℃ —35 ℃, until the walnut is dry and comes out. When baking, if the oven temperature is too high, the fire should be controlled in time to reduce the temperature of the oven; 5 to 15 hours after entering the oven, all the dehumidification equipment should be turned on and the moisture should be drained as soon as possible; walnut drying process walnut drying process walnut drying process to avoid The fire is too intense in the early stage, and the stone fruit should be heated gradually and simultaneously at the same time, so that the internal drainage of walnut kernels will be uniform and thorough, preventing walnut kernels from yellowing. Walnut drying process In the early stages of the walnut baking process, in order to ensure a balanced discharge of water from walnut kernels, it should not be turned. 2. Baking method of household walnut oven “New household walnut smoke-free baking room” is a new type of walnut drying equipment with intelligent temperature control and smoke-free pollution. Walnut drying technology. Walnut baking equipment. The amount is about 300kg. For the convenience of farmers, the baking temperature is set to about 45 ° C. During the entire baking process, you only need to manually add fuel such as firewood and coal, automatically control the temperature, and dehumidify in time. About 10 minutes before baking, fire and start to preheat the baking room. After that, the freshly peeled nuclei are evenly loaded on each layer of iron sieve in the baking room and continuously heated. Close the oven door, open the cold air window and the moisture exhaust window during the baking process. The baking time is about 36 hours. Walnut dryer drying process: The first stage-timely entering the warehouse to dehumidify (30-35 ℃ → 12-15 hours) 8 hours after peeling the green skin, put it in the warehouse and dehumidify and bake, the dehumidification temperature is 30-35 ℃ , The baking time is 12-15 hours, water is lost on the surface of the husk, and the moisture is removed when the color changes from dark brown to brown. The second stage-fixed color initial roasting (50 ℃ → 12 hours) After the dehumidification is completed, the fixed color initial roasting is started, the temperature is raised to 50 ℃, the baking time is 12 hours, and the drying is completed. Ren has fixed his color, and is 70% dry, but he can still take off his clothes. The third stage-Wenhuo dried kernels (30 ℃ → 16 hours) After the fixed color drying period ends, the dried kernels enter into the dried kernel phase. The temperature is controlled at 30 ℃ for about 16 hours. At this time, the water content of stone fruits reaches about 10%. After the dried kernel phase, the fire can be discarded, and the stone fruit on the oven can be satisfactorily covered with a sackcloth bag, and kept warm for several hours, so that the moisture in the upper stone fruit will continue to volatilize, and the upper and lower stone fruit will dry relatively evenly.