Color stability and change in bioactive compounds of red beet juice concentrate stored at different temperatures.

In the present study, effect of storage temperature (25°, 35° and 45 C) and light (with/without aluminum foil) on betalain content, color stability and bioactive compounds of concentrated red beet juice were investigated. Degradation of betalains and change in total phenolics content followed first-order kinetics while changes of L*, a*, b* and C* values and antioxidant capacity fitted zero-order kinetic. It was determined that the reaction rate constants of betacyanin and betaxanthin degradations in red beet juice concentrates increased with increasing storage temperature and time.