Studuy Of Stability And Application Of The Anthocyanin Extracted From Kyoho Grape

Owing to the frequent occurrence of synthetic pigment safety accidents, such as tainted steamed buns, excessive addition of imported black chocolate with sunset yellow etc, nutrient, safe and healthy natural pigment had been attracted more and more concern by scientists. Anthocyanin, a natural common water soluble plant pigment, is beneficial to human health due to its physiological activity of prevention of cancer, antiaging, curing of cardiovascular disease, and so on. However, it is vulnerable to the external condition, resulting to low stability and degradation. Herein, the extraction process, stability, antioxidant activity and application of anthocyanin, extracting from Kyoho grape(KGA), had been studied. Which would provide reference for wide application of anthocyanin. The work can be summarized as follows:Firstly, anthocyanin of Kyoho grape was extracted using malic acidified water. Optimum extraction condition, obtained via single-factor experiment and response surface experiment, were: 0.7% malic acid aqueous solution as extraction solvent, ratio of liquid to material of 11:1ml/g, digesting for 28 min at 52? for three times. Then the oretical content of anthocyanin was 269.2mg/100 g and that of measured was 261.1mg/100 g, the relative error of 3.01%, which indicated that the model can well predict the extraction process of KGA. Moreover, the amplifying experiment in the laboratory shows preferable extraction rate of KGA of 5.78%.Secondly, effects of temperature, illumination and ethanol concentration on the stability of KGA were further studied. Under the condition of low temperature and low pH value, preservation rate of KGA decreased slowly. The preservation of KGA decreased gradually in thermal treatment. And illumination broke the stability of anthocyanin, preservation of KGA decreased gradually after extension of illumination time; the preservation of anthocyanin also decreased gradually with the increase of ethanol concentration. Additionally, the degradation reaction of KGA are conform toed the first order kinetic model.Thirdly, the co-pigments, such as organic acids and antioxidants, would influence the stability of KGA. Upon addition of 7 organic acid, absorbance of KGA solution increased, and the copigment of caffeic acid and cinnamic acid were better than others. After addition of 5 antioxidants, absorbance of KGA solution increased; and among them, the tea polyphenol was the best co-pigment. Thus, they can be added appropriately into foods and drinks in real application.Finally, upon addition of KGA, fermentation time of yogurt shortened and number of lactic acid bacteria increased. Furthermore, KGA yogurt showed capability of free radical scavenging, including DPPH free radical, hydroxyl radical and superoxide anion. Added with the natural pigment mixture of KGA, sodium copper chlorophyllin, monascus pigment and gardenia blue into yoghurt, yoghurt acquired not only with colors but also more nutritional ingredient, larger content of lactic acid bacteria and stronger capability of antioxidant activity.