Dried fruit production methods vary, with common ones including air drying, oven drying,vacuum freeze dried, vacuum frying, and stir-frying. The following describes each method:
Air drying:
This is a traditional method in which fruits and other ingredients are exposed to direct sunlight or a well-ventilated area to allow them to naturally dehydrate and dry. Examples include raisins and dried longans, which are often produced using this method. This method retains most of the dietary fiber and sugar, but with a small loss of vitamin C and antioxidants.
Advantages: It requires no special equipment, is simple and easy to operate, and has low production costs. However, the drying process requires relatively extensive management.
Disadvantages: The drying process is slow and time-consuming, and the drying process cannot be manually controlled. Product quality is relatively poor and is significantly affected by climate.
High-temperature drying:
Heating equipment raises the ambient temperature, accelerating the evaporation of water from fruits and other ingredients, thereby achieving the desired drying effect. For example, dried kiwifruit is typically baked at high temperatures, resulting in a soft and elastic texture. However, high temperatures can lead to a significant loss of nutrients such as vitamin C.
Advantages: Rapid drying and high efficiency, allowing dried fruit to be produced in a short time.
Disadvantages: High temperatures can cause a significant loss of nutrients, such as vitamin C, and may also alter the color and taste of the dried fruit.
Low-temperature drying:
Generally, an oven or dedicated dryer is used, maintaining a low temperature range (e.g., 50-80°C) for a long time to bake ingredients such as sliced fruit. This method is suitable for homemade dried apples and dried strawberries, as low-temperature drying effectively preserves the fruit's nutrients and flavor.
Advantages: Effectively preserves the fruit's nutrients, color, and flavor, resulting in high-quality dried fruit.
Disadvantages: Long drying times, the need for specialized equipment, and relatively high production costs.
Vacuum freeze-drying:
Fresh fruit is frozen directly in a cold storage after harvest. Then, under a vacuum, the ice is sublimated into water vapor, achieving dehydration and drying. Dried fruit produced using this method, such as dried strawberries, are oil-free, low in fat, retain most nutrients, such as vitamin C, and have a crispy texture. Advantages: It can retain the nutrients, color and taste of dried fruits to the maximum extent, making the dried fruits loose and spongy, crispy, non-fried and low in fat.
Disadvantages: Large equipment investment, high production cost, complex drying process, and high energy consumption.
Vacuum frying:
Put fruits and other raw materials into oil under vacuum environment for frying. Since the vacuum environment reduces the boiling point of the oil, the water in the raw materials can be evaporated quickly at a lower temperature to achieve the drying effect. For example, dried bananas are often made by vacuum frying, which tastes dry, oily and crispy, but the dried fruits made by this method will lose a lot of vitamins and bring additional fat intake.
Advantages: Short heating time, good nutrition retention, oil oxidation is inhibited in an oxygen-deficient environment, and puffing occurs during the vaporization of water, which can improve the taste and flavor of food.
Disadvantages: The high fat content of dried fruits will bring additional health burden to the human body, and trans fatty acids and carcinogens may be produced during the frying process.
Stir-frying:
For some nuts, such as walnuts, peanuts, melon seeds, etc., stir-frying is often used. Put the nuts, salt, sand, etc. into the pot, stir-fry over medium or low heat until the nuts are cooked and have a fragrant and crispy taste.
Advantages: It can make nuts have a fragrant and crispy taste, increase appetite, and the production process is relatively simple and time-consuming.
Disadvantages: It is easy to have uneven frying, which causes some dried fruits to burn, affecting the taste and quality. At the same time, more salt, sugar and other seasonings may be added during the frying process, increasing the calories and sodium content of dried fruits.
Honey-made:
Soak fruits and other raw materials in honey or syrup, and after a period of soaking, take them out and dry them in the sun or bake them. For example, to make honey-made green plums, first soak the green plums in honey, then take them out and dry them after one to two weeks, or put the soaked green plums and syrup into the pot together and boil them, then boil for 10 minutes, put them in the jar with the soup and candied for 24 hours, boil them continuously for 3-4 times, and take them out when the green plums become translucent, drain the syrup, and then dry them.
Advantages: It can increase the sweetness and flavor of dried fruits, making the dried fruits taste richer. At the same time, sugar has a certain preservative effect during the honey-making process, which helps to extend the shelf life of dried fruits.
Disadvantages: Dried fruits have a high sugar content and a significant increase in calories. They are not suitable for diabetics, obese people, etc., and the vitamin C contained in fresh fruits is basically completely destroyed during the long cooking process.
Vacuum freeze-dried fruits have unique advantages over dried fruits made by other methods:
Maximum nutrient retention: Low-temperature vacuum environment avoids high-temperature damage, completely retains vitamins (such as vitamin C, A, E), antioxidant ingredients (anthocyanins, flavonoids, etc.), and there is no problem of water-soluble or fat-soluble nutrient loss.
Unique and crispy taste: After the water molecules sublimate, a porous structure is left, which brings a crisp taste, which is in sharp contrast to the soft, tough or greasy taste of other methods.
Outstanding health friendliness: No additional fat is added, no preservatives are required, and it is natural and healthy; it has little irritation to the gastrointestinal tract, is easy to digest, and has a low blood sugar fluctuation range, which is suitable for diabetic patients.
More practical: After dehydration, it is light in weight and small in size, easy to store and carry for a long time, and can replenish nutrition anytime and anywhere.
