White chocolate has in its basic formulation, sugar, cocoa butter, milk solids, whey, soya lecithin and aroma [1]. Quality loss caused by loss of white color (browning), during its storage is considered the main reaction which limits the shelf-life of this product [2]. Sugar, fat and milk are susceptible to browning reactions, mainly the Maillard reaction. The reaction also depends on the conditions of humidity and temperature, as well as on changes to these conditions, during chocolate storage. The main objective of this research was to determine the kinetic data (constant and order of reaction, activation energy, Q_(10)) of transformations that entail loss of quality in white chocolate. The parameters provide information about the degradation of products over time. For the kinetic study the samples were stored at approximately 82% RH to accelerate the reaction, at 10, 20 and 30 °C. Three formulations of chocolate were made: with whey (Formulation 1), with skim milk (Formulation 2) and another with one ingredient supposed to maintain the color (Globe? Chocosystem) (Formulation 3). White chocolate samples were produced in the pilot-plant: mixing, refining, conching and tempering. To determine the kinetic values, the samples were monitored for the variation of color (CIELAB values L*, a*, b*) over time. For kinetic parameters first was determined the order of reaction, by charts of the constant k reaction. The values of ln k were plotted as a function of inverse temperature (Arrhenius chart). Through the values of the slope of the straight line it was calculated the Ea (Ea). The calculation of Q_(10) was done according to the Ea, as shown in Q_(10)=10((Ea/(0.46xT^2)). The values of Ea (kcal/ gmol.K), and Q_(10) obtained for Formulations 1, 2 and 3 were: 25.43 and 4.0; 38.27 and 9.39; 25.00 and 2.0, respectively.
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