How to use a belt dryer to dry peppers?
1.Pretreatment stage
Picking and transportation: Choose peppers that are ripe, normal in color and have intact fruits. Good ventilation is required during transportation and stacking, and the stacking height should not exceed 1 meter and the time should not exceed 36 hours to prevent mildew.
Removal of impurities: Remove stems, leaves, dust and other debris.
Initial drying (stepping on the pile to sweat):
The initial moisture content of the pepper is high (75%~85%). First, dry it for the first time until the moisture content is about 50%, and then step on the pile to sweat. This step helps the chili oil penetrate to the surface, making the color of the dried peppers uniform, ruddy and smooth.
2.Drying stage
Temperature control:
The first stage (before the moisture content is 50%): Use low temperature and slow baking (46~50℃) to avoid high temperature from damaging the quality of the peppers.
The second stage (below 50% moisture content): heat up to 50~55℃ to accelerate drying.
Overall temperature range: generally controlled at 60~70℃, too high will affect the color and capsaicin.
Paving thickness:
The pepper is laid at a thickness of 20~30 cm. If it is too thin, the heat utilization rate is low, and if it is too thick, the hot air is difficult to penetrate, which affects the drying effect.
Ventilation and dehumidification:
The moisture content of fresh peppers is high (about 80%), so ventilation and dehumidification need to be strengthened. The wet bulb temperature is maintained at 38~39℃, and the dry-wet bulb temperature difference is maintained above 6℃.
Multi-layer mesh belt drying:
The peppers are laid evenly from the feed port, falling layer by layer with the mesh belt, and each layer is turned over to make the drying more uniform.
Hot air penetrates the mesh belt from the bottom, takes away moisture, and improves drying efficiency.
3.Post-processing stage
Rehumidification: After drying, the peppers have a low moisture content (about 14%) and a brittle and hard texture. They need to be rehumidified indoors to absorb a small amount of moisture to soften them for easy packaging.
Selection and packaging: Screening after rehumidification to remove unqualified products. Pay attention to moisture-proof during packaging to avoid mildew.
4.Equipment selection and optimization
Mesh belt material: 304 stainless steel mesh belt is recommended, which is corrosion-resistant and hygienic.
Heat source selection: Electric heating, steam, hot air furnace or air energy heat pump can be used, the latter is energy-saving and temperature-stable.
Automation control: Modern mesh belt dryers are equipped with temperature and humidity sensors and automatic adjustment systems to ensure uniform drying.
5.Precautions
Avoid excessive turning: Reduce turning during secondary drying to avoid affecting the appearance and quality of the peppers.
Prevent moisture and mildew: After drying, it needs to be properly stored and the warehouse should be kept dry and ventilated.
Through the above steps, the mesh belt dryer can achieve efficient and high-quality pepper drying, which is suitable for a variety of pepper varieties such as chili peppers, line peppers, and lantern peppers.