VITAMIN-C DESTRUCTION DURING THE COOKING OF A POTATO DISH

The kinetics of vitamin C destruction during the cooking of a potato d ish were measured. Five domestic cooking apparatuses, including a supe rheated steam oven, a free convection oven, a forced convection oven, a microwave oven and a pressure cooker, were compared. Whatever the co oking condition, when the residence time was equal to the cooking time the reduced quantity of vitamin C remaining in the potato dish was ap proximately 0.7. A model considering the thermal and the enzymatic des truction of vitamin C and the thermal deactivation of enzymes was prop osed. The parameters of the model were identified using the results of the cooking experiments and isothermal kinetics of vitamin C destruct ion in potato extracts. The simulations showed that the loss of vitami n C at the cooking time was mainly due to the enzymatic destruction. A prolonging of the residence time resulted in additional losses by the rmal destruction. A low water content and the presence of air in the c ooking atmosphere further increased the destruction rate. (C) 1995 Aca demic Press Limited