Application of vacuum freeze drying technology in food (2)
Characteristics of vacuum freeze-dried food
Food freeze-drying has many characteristics, and the technology is currently in the leading position of food preservation technology.
The color, aroma, taste and nutrients of the food itself can be preserved. The sensitive and highly oxidizable foods are usually difficult to preserve and are susceptible to microorganisms and enzymes. Freeze-drying can be used at low temperatures (-40 ° C). And the high degree of anoxic state preserves the color, aroma, taste and nutrients of the food, and minimizes the loss. Taking banana products as an example, the products obtained by vacuum freeze-drying have the best flavor compared with the three methods of hot air drying, microwave drying and vacuum freeze drying.
At the same time, the loss of protein and other fat-soluble vitamins (VA, VD) in foods such as meat, eggs, vegetables and sweet corn treated by vacuum freeze-drying technology is 0%, and the loss of water-soluble vitamins such as VC and β-carotene Only 5%. Taking spinach as an example, the vitamin retention rates after vacuum freeze-drying, hot air drying, dry drying and drying were 93%, 59%, 7% and 4%, respectively. According to foreign research reports, after one or two years of freeze-dried food, the nutritional level can still match fresh food.
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