73C-33 |
Effectiveness of edible coatings from cellulose derivatives to reduce fat absorption in deep fat frying |
M. A. GARCIA1, C. Ferrero, N. Bertola, M. Martino, and N. Zaritzky. (1) CIDCA, CONICET, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, 47 y 116 (1900), La Plata, Argentina Deep fat frying is a widely used method for preparing foods with a particular taste and texture, providing increased palatability. However the absorption of oil renders the fried food unhealthy because the consumption of excess of fat in the diet has been linked to coronary heart disease. The objectives of the present work were i) to develop edible coatings from cellulose derivatives to reduced oil uptake in fried foods and ii) to analyze the thermal gelation of these hydrocolloids. Aqueous suspensions of 1% Methocel A4M (based on methylcellulose) and of 2% K100LV and E15LV (based on methylcellulose and hydroxypropyl methyl cellulose) were analyzed in a Haake RV2 Viscometer to evaluate thermal gelation. Deformation sweeps to determine the linear viscoelastic range and frequency sweeps to measure the elastic (G'), viscous (G") and complex (G*) moduli were carried out in an Oscillatory Rheometer Haake CV20. A4M suspensions showed the highest G´ and G* values and were used in the coating formulations; to improve coating performance, up to 1% sorbitol was added as plasticizer. The coatings were applied by immersion to french fries and dough discs. Sunflower oil was used for deep frying. The optimum frying conditions (time-temperature) were determined by a sensory panel. The color of the fried samples was measured using a Minolta Colorimeter. Fat content was determined by combining a preliminary batch extraction process with a semi-continuous extraction in Soxhlet. The addition of plasticizer improved the barrier properties of A4M coatings, using 0.5% for potato samples and 0.75% for dough as the optimum sorbitol concentrations. The application of the best coating formulations reduced up to 35.2% oil up-take and retained 25.7% more water for dough samples and 41% and 6.3% for french fries, respectively. The sensory panel showed that coated samples did not differ significantly from uncoated ones.
Session 73C, Food Engineering: Transport Processes and Kinetics
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