Although fruit drying may seem simple, improper operation can easily cause the finished product to turn black, moldy, dry and hard in taste, or lose nutrients. The following are the most common mistakes and pit avoidance guidelines during fruit drying: 1 Improper preprocessing and uneven slice thickness: This is the most common error. If the thickness of the same batch of fruit slices is not the same, it will cause the thin ones to be burnt and crispy, while the thick ones still contain moisture inside, making them prone to mold later on. It is recommended to maintain a cutting thickness of around 3-5 millimeters and try to make it as uniform as possible. Neglecting color protection and antioxidant properties: Fruits such as apples, pears, and peaches are rich in polyphenol oxidase, which can quickly turn brown and black when exposed to air after cutting. If not treated with color protection (such as soaking in light salt water, lemon water, or vitamin C solution), the color after drying will be very dull, affecting appetite. Without withering/blanching: For some fruits with a hard texture or bitter taste (such as persimmons, certain varieties of apples), direct drying can result in the finished product being stiff or having a poor taste. Proper use of hot water blanching (withering) can disrupt enzyme activity, maintain color, and improve the taste of dried fruits. two Drying parameter setting error: Initial temperature too high: Using high temperature (such as 70 ℃ or above) for drying from the beginning can cause the fruit surface to quickly crust (i.e. "surface hardening"). This will seal off the channel for internal moisture to evaporate outward, resulting in "dry outside and wet inside", which is not only difficult to completely dry, but also prone to deterioration from the inside. The correct approach is to first cool down (about 45 ℃ -50 ℃) to remove moisture, and then gradually raise the temperature (to around 60 ℃). Poor dehumidification: Drying is not only about "heating", but more importantly, "dehumidification". If the exhaust vent of the dryer or oven is blocked, or if the environmental humidity is too high and moisture cannot be discharged, the fruit is actually being "steamed" rather than "dried", which can easily become sour or moldy. Excessive drying time: Excessive drying can cause the sugar in the fruit to become burnt, the color to darken and turn black, the taste to become as hard as stone, and the heat sensitive nutrients such as vitamins to be almost completely lost. three Placement and operation errors: Stacking too tightly: Overlapping fruit slices or laying them too thick can seriously hinder the circulation of hot air, resulting in uneven heating. It is necessary to ensure sufficient gaps between the fruit slices and lay them flat on the grill. Frequent opening of doors/lids: Frequent inspection during the drying process can result in a significant loss of heat and dry air, as well as drastic temperature fluctuations. This not only prolongs the drying time but also affects the texture of the dried fruit. four The error in the storage process was not completely cooled before sealing: there may still be residual temperature inside the fruit slices just after drying. If immediately packaged and sealed, the emitted heat will condense into water droplets inside the packaging bag, causing the dried fruit to mold within a few days. It must be thoroughly cooled at room temperature before packaging. Lack of moisture regain treatment: If the "moisture regain" treatment is not carried out after drying, the moisture content at the edges and center of the dried fruit may not be consistent. Dried fruit can be placed in a sealed container for 1-2 days to allow the moisture to redistribute evenly, and then undergo long-term sealed storage.

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