Modern nutritional studies have found that tomatoes have extremely high nutritional value, low calories, anti-oxidation, and anti-cancer; they can remove freckles, beautify, prevent aging, and lose weight. Tomato powder is suitable for both internal and external use. It is suitable for low-fat meals, weight loss and beauty.
Dried tomatoes have a unique sweetness and last longer than fresh tomatoes. Aside from some vitamin C loss, drying tomatoes doesn't alter any of the fruit's nutritional benefits, and the added flavor and ease of storing dried tomatoes are benefits of the preservation process.
It is worth mentioning that tomatoes contain lycopene, which is a powerful antioxidant that helps delay aging and resist stress. And can balance moisture and oil secretion. Tomato powder is slightly changed to make different facial masks such as cleansing, repairing, spot removal and whitening. At this point, tomato drying technology is needed.
Drying is an important link in the production of dehydrated vegetables. In general, fresh vegetables are 75%-95% water, while dehydrated or dried vegetables are about 5% to 15% water.
At present, there are two main drying methods for tomatoes: natural drying and artificial drying and dehydration. Natural drying is a traditional drying method, and it does not need to spend money. It only needs to be air-dried on site. It is an economical and environmentally friendly drying method.
But the weather conditions have a serious impact on it. In rainy weather, it cannot be dried, and even a large number of vegetables will become moldy and deteriorated due to not being dried in time. On windy days, tomatoes are not only easily blown away by the wind, but are also easily contaminated with dust and particulate matter, which affects their appearance. Sun exposure is simple and economical, but there is no guarantee of drying quality, especially the color of vegetables, and it is also prone to moth-eaten in later storage.
Dehydrated vegetable drying equipment is a new type of environmentally friendly and energy-saving food dryer. The whole drying process requires no coal, no wood, no charcoal burner, no boiler, no steam, and only a small amount of energy to drive the compressor can obtain the required Heat, automatic operation of drying process, automatic thermal dehumidification, and automatic dehumidification of humidity, avoiding production pollution and other problems; closed baking environment, not affected by external weather, products do not need to be turned over, saving time and effort, greatly shortening the drying time cycle and improve product quality.
There are many drying methods for tomatoes, mainly freeze drying, puff drying, drum drying, foam layer drying and spray drying.
1. Freeze Drying
This method uses low temperature to freeze the tomato concentrate, and then sublimates the water in a high vacuum state for drying. The resulting tomatoes still retain their original structure without compromising its original shape and size. Thus, freeze-dried particles have a porous structure that retains the space originally occupied by moisture without collapsing, thereby facilitating rapid rehydration of the product. However, this method consumes a lot of energy, and the freeze-drying equipment is relatively expensive, so the cost of the obtained product is high.
2. Spray Drying Method
Tomato concentrate slurry should be homogenized prior to spray drying. The homogenization pressure is generally 150 to 200 kg/cm 2 . Generally, a centrifugal or two-fluid spray dryer with a cooling jacket on the tower wall (double-layer tower wall, the temperature of the inner wall of the drying chamber can be cooled by air) is used for drying; if the heating medium is pre-dehumidified dry air, Then the inlet air temperature during drying is generally about 150-160°C, the outlet air temperature is 77-85°C, and the feed concentration is generally 20%-30%.
There are already some modified spray drying equipment on the market that can be used to process fruit and vegetable powder. Some use air as drying gas, and use a medium inlet air temperature of 75-95 °C for drying, which can improve the production speed; others use dehydrated air as drying gas, and at a lower inlet air temperature (25-50 °C) °C) for drying. So this method is the best choice for drying tomatoes.
Tomato Spray Drying Principle:
The working principle of the system: the air is filtered and heated, and enters the air distributor at the top of the dryer, and the hot air enters the drying chamber uniformly in a spiral shape. The feed liquid passes through the high-speed centrifugal atomizer at the top of the tower body, and is sprayed (rotating) into extremely fine mist-like liquid droplets, which can be dried into finished products in a very short period of time in co-current contact with hot air. The finished product is continuously output from the bottom of the drying tower and the cyclone separator, and the exhaust gas is evacuated by the fan.
The working principle of the atomizer: when the material liquid is sent to the feeding pipe of the atomizer, it is quickly sent to the high-speed rotating atomizing plate after one or two distributions of the material and liquid. The surface of the rotating atomizing disk stretches into a thin film, and moves to the edge of the disk at an increasing speed. When it leaves the edge of the disk, the material liquid is atomized, with drop-shaped, filamentous and film-shaped splits. The splitting is mainly related to the rotating speed of the atomizer, the feeding amount, the properties of the material and liquid, and the shape and diameter of the atomizing disc, and the size of the droplet mainly depends on the peripheral speed of the atomizing disc.
Tomato Spray Drying Features:
The drying speed is fast, and the surface area of the material liquid is greatly increased after being atomized by the high-speed centrifugal atomizer. In the hot air flow, 95%-98% of the water can be evaporated in an instant, and the drying time is only a few seconds. It is especially suitable for heat-sensitive materials. dry.
The product has good uniformity, fluidity and solubility, high product purity and good quality. The production process is simplified and the operation control is convenient. For liquids with a moisture content of 40-60% (special materials can reach 90%), it can be dried into powder products at one time. After drying, there is no need to pulverize and screen, reducing production processes and improving product purity. The particle size, bulk density and water content of the product can be adjusted by changing the operating conditions within a certain range, and the control and management are very convenient.
Food Dryer/Vegetable Drying Equipment Drying Process Of Tomatoes:
Tomato raw materials, screening, sorting, cleaning, cutting, blanching, drying, drying products, soft, packaging.
Raw Material Selection:
Tomatoes are selected, with a moderate size of 4.0-4.8cm in diameter, smooth surface without scars, bright red peel, and similar maturity.
Rinse, blanch, peel, then quarter or thinly slice tomatoes and soak in colorant for 20 minutes.
Drying Of Tomatoes:
Spread the tomatoes on the pan, put them in the vegetable dryer and start drying.
The drying temperature is controlled at 40 ~ 70 ℃, and the moisture is continued to be dried, and the tomatoes are dried to 20%.
The drying oven produced by ZZKD has stable performance and easy operation. In addition, we also have vacuum drying ovens, blast drying ovens, hot air drying ovens, etc. and drying production equipment. 13 years of production and export experience and a series of ISO9001 and CE certificates, with warehouses in the United States, Spain and Thailand.
If you want to know about our products, or want to buy our equipment, please feel free to contact us, ZZKD will provide you with the best price for drying ovens.