30D-24 |
Kinetics of color development in crust of donuts during deep-fat frying |
M. E. SOSA-MORALES and J. F. Vélez-Ruiz. Chemical and Food Engineering, Universidad de las Américas - Puebla, Ex-Hda. Sta. Catarina Mártir, Cholula, Puebla, 72820, Mexico
Frying of foods is a common and antique method in food preparation. There are reports that explain the complexity of the process of some fried products. Physical properties and sensory attributes of fried snacks and potatoes have been reported, being color an important parameter for acceptability. Donuts are baking products highly consumed around the world, they are generated by frying, and information about the process and the product is limited. The objective of this study was to know the evolution of color in the crust during deep-fat frying of donuts. Yeast-leavened donuts were prepared in deep-fat fryer at 180, 190 and 200°C, using sunflower oil. Color crust was measured by reflactance with Hunter parameters L, a and b. Samples were taked each 15 sec. Luminosity (L) was the most significative paarameter, a and b did not any tendency. L decreased when frying time (t) and oil temperature (T) increased. Applying theory of kinetics of reaction, the L change adjusted to kinetic of order zero (r’s>0.90), and the velocity of the reaction, k, was obtained. k increased when T raised: 0.0026, 0.0031 and 0.0032 min-1 for 180, 190 and 200° C, respectively. Activation energy was calculated for the process, being 4.44 kcal/mol. Evolution of color in crust of donuts during frying adjusted to kinetic of order zero. The evaluated small activation energy show that the frying of donuts is a very fast process (refered to reach the color and crust formation) in the food process engineering.
Session 30D, Food Engineering: Physical and chemical properties
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