Frying process transfer during

Mass transfer during frying is not only characterized by the movement of water in the form of vapor from the food into the oil, but also by the movement of oil into the food. Frying is a dehydration process where water escape leaves empty spaces within the crust structure, which in turn determines the volume available for oil absorption. In fact, the amount of oil uptake has been shown to be directly proportional to... 

Moreira, R. G., Palau, J., and Sun, X. (1995b). Simultaneous heat and mass transfer during the deep fat frying of tortilla chips. J. Food Process Eng. 18,307-320. 

Factors which affect heat and mass transfer during frying are the thermal and physical-chemical properties of the food and oil, the food geometry, and the oil temperature. Many variables are involved in the traditional flying process of potatoes ... 

Oil acts as a heat transfer medium during the frying process which rapidly heats, cooks, and sometimes puffs, dehydrates, or forms a crust around the product. The mechanics of deep fat frying are shown in Fig. 34.32.173 The entering material carries oxygen that temporarily aerates the hot oil, and water that forms steam, with both rapidly swept out... 

In the models described above, a constant convective heat transfer coefficient was assumed during the hole frying process, or two independent values were considered (1) one for the initial frying stage... 

Hubbard, L. J. and Farkas, B. E. (1999). A method for determining the convective heat transfer coefficient during immersion frying. ]. Food Process Eng. 22, 201-214. 

This complex unit operation involves significant microstructural changes in fact, most of the desirable characteristics of fried foods are derived from the formation of a composite structure a dry, porous, crispy and oily outer layer or crust, and a moist cooked interior or core, whose microstructures form during the process (Bouchon et al., 2001). The high temperatures (around 160 and 180°C) cause water evaporation, which is transferred from the food towards the surrounding oil, whereas oil is absorbed by the food replacing part of the released water. This process results in products with a unique flavor-texture combination (Mellema, 2003). 

The food undergoes a simultaneous process of heat and mass transfer as well as many chemical reactions during frying. This is a complex process as summarized below ... 

Kalogeropoulos N, Chiou A, Mylona A, loaimou MS, Andrikopoulos NK (2007) Recovery and distribution of natural antioxidants (a-tocopherol, polyphenols and terpenic acids) after pan-frying of Mediterranean finfish in virgin olive oil. Food Chem 100 509-517 Cacace JE, Mazza G (2003) Mass transfer process during extraction of phenolic compounds from milled berries. J Food Eng 59 379-389... 

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