Study on the stability of red pigment from waxberry

The effects of pH value, temperature, light, metal ions and additives on the stability of red pigments from waxberry were studied.The results showed that the pigments were very sensible to acidity and alkalinity, and had a poor thermal stability, and oxidants (hydrogen peroxide),reductants (sulfite sodium) and the preservative (sodium benzoate) obviously degraded the tone of pigment.Citric acid, sodium chloride and vitamin C had influences on improving the pigments and sucrose had little influence on the pigment stability.The existence of Fe2+ and Cu2+ could increase the absorbance of the juice and make the color of juice darker,and K+,Ca2+,Na+and Zn2+ had little effects on the pigments.Exposure to indoor natural radiation and ultraviolet degraded the tone of pigments and dark room storage was good for the juice stability.