Color Changes Kinetics and Heat Transfer during Deep Fat Frying of Garlic Slice

Abstract

Heat and mass transfer phenomena that take place during frying cause physicochemical changes, which affect the colour and surface of the fried products. The effect of frying temperature on the colour changes and heat transfer during deep fat frying of garlic has been investigated. The colour scale parameters redness (a*), yellowness (b*) and lightness (L*), and color change intensity (∆E) were used to estimate colour changes during frying as a function of oil temperature and time. L* value of fried garlic decreased during frying but a* and b* values were increased. A first-order kinetic equation was used for each one of the three colour parameters, in which the rate constant is a function of oil temperatures. The results showed that oil temperature have a significant effect on the colour parameters. Different kinetic models were used to fit the experimental data and the results revealed that the power model was the most suitable to describe the color change intensity (∆E). Center temperature of garlic slice increased with increase in oil temperature and time during frying.