Thermal degradation kinetics of anthocyanins in Myrica rubra juice and concentrate

Thermal stability of anthocyanins in Myrica rubra juice is susceptible for degradation by factors like temperature and pH values. The degradation of anthocyanins led to the change of color, and the product quality is therefore influenced. This paper studied the thermal stability of Myrica rubra juice and concentrate under different temperatures and pH values. Results of kinetic study of the degradation process of anthocyanins in Myrica rubra juice suggeste that the degradation process is a first order degradation kinetic process. As the increase of temperature and pH value, the half-life degradation of anthocyanins and activation energy for the thermal degradation decrease significantly. Under the same condition, the half-life of concentrate is significantly lower than that of the juice. And the k and Ea values of concentrate are higher than that of the juice. The result indicate that anthocyanins are more stable in juice than in concentrate.