Vacuum frying versus conventional frying - An overview Academic Article uri icon

abstract

  • Deep-fat frying of foods usually is carried out under atmospheric conditions at temperatures near 190C. The problem that arises most often is excessive darkening or scorching of the product, even before the product is completely cooked. In addition, some of the oil decomposition products have been implicated in producing adverse health effects when fried oils degraded with continued use. Vacuum frying is a process that is carried out under pressures well below atmospheric levels (below 6.65kPa). Vacuum-fried products have higher retention of nutritional quality (phytochemicals), color is enhanced (less oxidation), and oil degradation is reduced compared to atmospheric frying. However, a de-oiling mechanism is necessary to remove the excessive oil absorption at the surface of the product. The main objectives of this paper are to review the literature on vacuum frying specifically on the effect of vacuum frying operating conditions such as pressurization and de-oiling mechanisms on the final product oil content. Product quality attributes as affected by atmospheric and vacuum pressures and fundamental modeling of the process are also discussed in this article. Vacuum frying is an efficient method to produce fruit and vegetable snacks with the necessary degree of dehydration without excessive darkening or scorching. While traditional frying (atmospheric pressure) can be used for a variety of products, delicate products like mango, apple, and pineapple chips can only be produced under vacuum frying. A vacuum frying process consists of the frying vessel, the vacuum pump, the de-oiling mechanism, and the condenser. Oil content, texture, flavor, and color are the most important fried product quality attributes. Oil uptake takes place during the pressurization step, when the vacuum is broken, and during cooling, when the product is removed from the fryer. Because of the high pressure differential during pressurization, the product must be de-oiled prior to this step. 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

published proceedings

  • EUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY

author list (cited authors)

  • Moreira, R. G.

citation count

  • 45

publication date

  • June 2014

publisher