Abstract This work evaluates the effect of temperature and soluble solids on the degradation rate of phenolic compounds, and antioxidant activity of extracts from Bixa orellana L. leaves. The temperatures were studied in the range of typical food processes (70-90 °C) and food storage (−20-37 °C). The results showed that the thermal degradation of the phenolic compounds follows first-order kinetics, in which the degradation rate depends on the temperature, the amount of soluble solids, and the pH. The loss of antioxidant activity also follows first-order kinetics. Under different storage conditions, the half-life times of the total phenols were in the range 40.72-202.47 days, while for the antioxidant activity, the half-times were from 55.87-68.83 days for the ABTS and from 57.85-107.03 days for the FRAP method. The antioxidant activity of the extracts follows the same pattern of thermal degradation as the phenolic compounds. Therefore, we conclude that antioxidant activity is due to its phenolic compounds.

Se estudió la respiración del mango cortado (Mangifera Indica L.), cv. Tommy Atkins, utilizando el método de sistema cerrado, a tres temperaturas (4, 20 y 35 °C). Se usaron dos modelos para estimar la concentración de gas, los cuales se ajustaron a través de algoritmos de regresión no lineal usando el software Matlab R2011a. Se ajustaron tres modelos matemáticos para predecir la tasa de respiración del sustrato. Un modelo basado en la cinética enzimática de Michaelis-Menten, y dos modelos basados en análisis de regresión, en uno de los cuales se incluyó una ecuación de saturación como una nueva propuesta en este campo. Los resultados evidenciaron el efecto positivo que tiene la temperatura sobre la tasa de respiración del mango. El modelo que mejor ajuste entregó para la velocidad de respiración del mango fue el modelo de Michaelis-Menten con un coeficiente de correlación ajustado de 0.9811 y 0.9747 para CO2 y O2, respectivamente, con un error medio relativo inferior al 10%.

Respiration of cut mango (Mangifera Indica L.) cv. Tommy Atkins was studied using the closed system method at three temperatures (4, 20 and 35 °C). Two models were used to estimate the gas concentration, which were adjusted through non-lineal regression algorisms using Matlab R2011a software. Three mathematic models, a model based on Michaelis-Menten's enzymatic kinetics, and two models based on regression analysis, in one of which a saturation equation was included as a new proposal in this field, were set to predict the substrate respiration rate. Results made evident the positive effect of temperature on mango respiration rate. The model with the best adjustment to mango respiration rate was Michaelis-Menten's with an adjusted correlation coefficient of 0.9811 and 0.9747 for CO2 and O2 respectively, with a relative mean error lower than 10%.