Color retention: Using a commercial vacuum fryer, the frying temperature is greatly reduced, and the oxygen concentration in the fryer is greatly reduced. Fried foods are not easily faded, discolored, browned. The color of the raw material itself can be maintained. For example, kiwifruit is highly susceptible to hot brown, but if vacuum fried, green color can be maintained. However, in the case of oil-soluble pigments such as carotenoid pigments and chlorophyll pigments, the pigments are easily dissolved during frying, so the raw materials should be pretreated before frying to keep the pigments stable.
Aroma preservation: vacuum frying, the raw material is heated in a sealed state. Most of the flavoring ingredients in the raw materials are water-soluble, do not dissolve in the fats and oils, and these flavoring components are further concentrated as the raw materials are dehydrated. Therefore, the vacuum frying technique can well preserve the aroma of the raw material itself.
Reduce the deterioration of oil: Deterioration of fried oil includes oxidation, polymerization, thermal decomposition, and water or steam is contacted with oil to produce hydrolysis. In the vacuum frying process, when the oil is under a negative pressure state, the gas dissolved in the grease quickly escapes a lot, the generated water vapor pressure is small, and the frying temperature is low, so the degree of deterioration of the grease is greatly reduced.
Preservation characteristics: crispy feeling is an important sensory index of vacuum fried products. To maintain the crisp state of the product, the moisture content should be controlled within 5%, preferably about 1%. Therefore, the problem of moisture absorption during storage must be carefully considered.
Oxidation of oils in vacuum frying products: Vacuum frying products have a porous structure and adsorb a layer of grease on the surface of the pores. This layer of grease cannot be removed by centrifugal de-oiling. Therefore, vacuum fried products have a certain oil content. Oxidation reactions occur when grease and oxygen are in contact. Therefore, when packaging vacuum-fried products, the air should be excluded as much as possible, or filled with inert gas for packaging. For products with long shelf life, some antioxidants can also be added.
Liuyi Machinery's industrial vacuum fryer is a continuous field study and research conducted by food production enterprises. It is heart-to-heart communication, taking long and short, adopting international advanced technology concepts. It combines with the actual situation of food production enterprises. We will continuously explore and improve to better meet the needs of customers. If you have any questions for the processing of fruits and vegetables, please contact us!