The mainstream dehydrated onion products in industrial production adopt a staged hot air drying process, and the details can be adjusted according to the product form. The core process is as follows:

1、 Standard Industrial Processing Flow

Raw material selection: Priority should be given to onions that are 80% mature, have a tight structure, and are free from pests and diseases. The dry matter content requirement should not be less than 14%, and white skinned varieties are more suitable for industrial dehydration processing.

Preprocessing: Cleaning and cutting: Peel off the outer skin, remove the head and tail, rinse with water and drain, then cut into slices, shreds, blocks or cubes according to product requirements. The thickness of the slices is generally controlled at 3-5 millimeters.

Blanching and pre cooking: Cut onions are blanched in boiling water above 150 ℃ for 2-4 minutes to help kill bacteria and soften tissues. Some processes may use water soaking for 10-15 minutes to remove some tear inducing components and reduce the spiciness.

Cooling and draining: After blanching, immediately rinse with cold water to cool down to room temperature, then shake the water with a centrifuge or manually press and drain. After draining the surface moisture, spread it out and air dry for later use.

Staged drying: The mainstream process dries in stages in an environment of 65 ℃~85 ℃, with an overall drying time of about 5-6 hours; There are also three temperature control schemes: initial drying at 93 ℃ for 1-1.5 hours → cooling down to 53 ℃ and dehydrating to a moisture content of 6%~7% → finally drying at 45 ℃ to a finished product moisture content of less than 3.5%. Gradual cooling can avoid burning.

Finished product packaging: After drying, natural heat dissipation is achieved, and non-conforming products are removed through sorting and inspection. The products are sealed and stored in a dry and sterile environment. The finished products should be stored in a cool, dry warehouse with a relative humidity below 70%.

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2、 Special process differences

Freeze dried onion powder process: First, the sliced onions are frozen at -15 ℃, then placed in a vacuum freeze dryer (vacuum degree 50-70Pa) for 5-7 hours to dehydrate, and finally crushed into 300-500 mesh fine powder. This process preserves more complete nutrients but has a processing cost three times higher than hot air drying.

Homemade dehydration process: It is recommended to control the temperature below 60 ℃. Cut the onions and lay them flat on a baking tray. Dry them with hot air circulation for 6-12 hours until the moisture content is below 10%. Then, put them in a sealed jar and store them at room temperature for six months.

3、 Production Reference

1 kilogram of fresh onion with skin can be processed to obtain 80-120 grams of dehydrated onion products. The yield fluctuation is mainly affected by onion variety, moisture content, and processing technology.

Linyi Yunpeng Food Co., Ltd. is located in Linyi City, Shandong Province. The company mainly engages in the production, research and sales of various dehydrated vegetable products for the Japanese market, including dehydrated garlic, ginger, onions, onions, horseradish, etc.