Vacuum Frying: An Alternative to Obtain High-Quality Dried Products

Vacuum frying is an alternative way to improve the quality of the fried food and could reduce the final oil uptake in the product. The product is heated at low pressure thus decreasing the boiling points of the frying oil and the water in the product. Moreover, the absence of air during vacuum frying may inhibit lipid oxidation and enzymatic browning, and therefore, the color and nutrients of samples can be largely preserved. Many food research projects involving snack food industries therefore attempt to understand oil uptake during the vacuum-frying process in order to control and reduce the fat content of fried products without deteriorating their desirable organoleptic characteristics. This article is an update of the state-of-the-art in vacuum-frying technology, showing the effect of pretreatments and frying conditions on quality characteristics of the products. Facts pertaining to equipment and operation conditions are included. On the other hand, mathematical models to describe oil uptake and water loss are also mentioned. The effect of this treatment on color, texture, and nutritional value of the final products is also discussed.