Modeling of Heat and Mass Transfer During Deep Frying Process. Chapter 12

CAMPAÑONE L; GARCIA M. A. ; ZARITZKY NOEMI

Mathematical Modeling of Food Processing (Contemporary Food Engineering)

CRC Press -Taylor and Francis Book

Lugar: New York- London; Año: 2010; p. 316 - 338

The frying process is considered one of the oldest cooking methods. It is used to cook food inoil and to confer unique textures and tastes; the organoleptic characteristics depend on the fryingconditions. Frying is usually done by the immersion of the product in oil at a temperature of150?200ºC, where a simultaneous heat and mass transfer takes place .Heat conduction occurs in the core of solid food and it is strongly influenced by the physical properties of the food that change continuously during the frying process  Simultaneously, heat transfer by convection takes place between the oil and the surface of the food. When the formation of bubbles begins, the heat transfer is accelerated because bubbles contribute to the turbulence in the frying medium. However, the formation of foam in the oil produces a significant decreasein the heat transfer rate . Convection heat transfer decreases as the amount of vapor decreases due to the depletion of water in the core of the food. The rate of heat transfer toward the food core is influenced by the thermal properties and viscosity of the frying medium and the agitation conditions. During the production of bubbles on the surface, forced convection becomes the main regimen.In the present chapter the following objectives are proposed:1. To model heat and moisture transfer during the deep-fat frying of food by solving numericallythe partial differential equations of heat conduction and mass transfer within thefood, which allows the prediction of temperature profiles and moisture concentrations, asa function of operating conditions.2. To validate experimentally the mathematical model with regard to the temperature profilesand the water losses from the food product.3. To relate OU measurements after the frying process with the effects of frying time onsample microstructural changes as well as on the growth of the dehydrated zone.4. To analyze the performance of applying an edible coating based on MC on a food modeldough system by measuring moisture content and OU in deep-frying process.5. To analyze quality attributes such as texture and color and to observe using scanning electronmicroscopy (SEM), the surface microstructure of coated and uncoated fried productsat different processing times