摘要：The effect of temperature on the degradation of anthocyanins in sour cherry and pomegranate juice samples was investigated. The samples of 45° and 15° Bx were prepared from the concentrate of 70 °Bx and stored at -18°, 5°, 20° and 37°C. During storage, the rate of anthocyanin degradation was investigated by determining the loss of anthocyanins in the samples taken at different time intervals depending on storage temperature. According to the experimental results the degradation of anthocyanins was fitted to first order reaction model. As expected, the rate of anthocyanin degradation increased by increasing the temperature. For instance, although the rate constant k= 0,534x10-3 day-1 at-18°C in pomegranate of 15°Bx. It increased to k= 184x10-3 day-1 at 37°C. In the same way, although the rate constant k=0.203x10-3 day-1 at -18°C in sour cherry, it increased to k= 94x10-3 day-1 at 37°C. The Arrhenius equation was used to describe the dependence of reaction on temperature. The degradation rate of anthocyanins in pomegranate juice and concentrates is higher than that of sour cherry samples. Therefore a rapid discoloration occurs in pomegranate juice and concentrates depending on temperature during storage. Moreover, although anthocyanins of sour cherry juice at its natural brix are more stable than those of its concentrates, anthocyanins of pomegranate juice concentrates are more stable as compared to those of pomegranate juice.
