Abstract: The hot water tank temperature, thickness of material loading and freeze-dried wharf pressure on freeze-dried time and freeze-dried quality of red onions were studied. The single factor test and the orthogonal test were drawn red onions. The better vacuum freeze-drying process parameters: water tank temperature setting of 55 ℃, material loading thickness of 30 mm, freeze-drying warehouses pressure 150 Pa. In this process parameters, the freeze-dried red onions yield of 6.9%, better sensory quality, the water-back was better, the color was green, fresh tissues like the oil rich flavor.

Key words: shui-li red onions, vacuum freeze-drying, process parameters