Kinetics of Color Change in Squash (Cucurbita maxima) During Frying by Immersion at Atmospheric Pressure and Vacuum Pressure

The goal of this study was to determine the kinetics of the change of color in squash (Cucurbita maxima) during frying by immersion under conditions of atmospheric pressure and vacuum. Methodologically, the color of the rind of the external surface of the product conditioning in geometry of cylinders circulars, was evaluated in terms of the parameters CIELAB concerning L*, a* and b* post-process of frying under conditions of temperature of 150, 170 and 190°C, pressure of 40 and 80 kPa and during the time of processing time of 30 to 270 sec in intervals of 60 sec. The darkening of the surface of the product by effect of the process of frying in both procedures was evident in the decrease of the parameter L* as well as the parameters a* and b*, being more severe effect of darkening of the frying atmospheric higher temperature and experiencing changes of zero order for L*, zero for a* and first order for b*. The unit of the temperature and the speed of the reaction is explained by the Arrhenius equation. The activation energy obtained for the parameters of L*, a* and b* were 58.050, 13.709 and 53.545 kJ/mol and 32.082, 13.336 and 63.768 kJ/mol for the process of frying to the vacuum and frying in atmospheric conditions respectively.