Study On Component Analysis, Stability And Oxidation Resistance Of Different Anthocyanins

Anthocyanins is present with an important class of metabolites, and they are safe,non-toxic and resource-rich natural colorants. Despite the great potential ofapplication that anthocyanins represent for food, pharmaceutical and cosmeticindustries, their use has been limited because of their relative instability, rather lowextraction percentages and the quite complex structure. Currently, most investigationson anthocyanins are focused on solving these problems. In this paper, we selectedfive different biological sources of anthocyanins from purple sweet potato, purplecabbage, blueberries, blackberries and black rice, exstract anthocyanins from themand study the relationships of their structure, stability and oxidation resistance.Thefollowing studies in this thesis have been done:1. The species of anthocyanins from five different samples were analyzed byHPLC/MS and MS/MS method. In the study, the anthocyanin compositions in blackrice bran are mainly cyanidin-3-glucoside, cyanidin, peonidin-3-glucoside andcyanidin-3,5-glucoside, and their contents are respectively311.53μg/mg,46.73μg/mg,26.08μg/mg and11.19μg/mg, account for78.76%,11.81%,6.59%and2.83%of thetotal content; The anthocyanin compositions in black berry are similar with black ricebran, and they are cyanidin-3-glucoside, cyanidin, peonidin-3-glucoside andcyanidin-3-dioxalylglucoside, their contents are respectively159.54μg/mg,83.93μg/mg,6.18μg/mg and4.64μg/mg, which account for62.74%,33.01%,2.43%and1.82%of the total content; The major of anthocyanins of the blueberry aremalvidin, delphinidin, petunidin, cyanidin, peonidin and their correspondingglycosylation compounds. Malvidin anthocyanins take the highest content, and theircontent is149.61μg/mg，which account for39.03%. And the content of peonidinanthocyanins is lowest, only account for5.46%; The anthocyanins from the purplesweet potato are made up of cyanidin and peonidin derivatives. The contents ofpeonidin pigments are about five times more than cyanidin pigments. The percentageof glycosylated anthocyanins is low, account for15.34%, and the rest is acylatedanthocyanins. The acylated groups have caffeic acid, ferulic acid, hydroxy-benzoicacid and sinapic acid, and the highest content is caffeic acid acylated peonidin,account for58.69%; The major ingredients of anthocyanins from purple cabbage arecyanidin, peonidin and malvidin pigments, respectively account for90%,5.21%,4.80%of the total content. The content of glycosylated anthocyanins is only account for5.46%,and the others are acylated cyanidin anthocyanins.The acylated groupshave sinapic acid, caffeic acid, ferulic acid, and p-coumaric acid. Sinapic acidacylated cyanidin have the highest content, which is277.36μg/mg, accout for70.32%.2. Under the conditions of25℃, we studied five different anthocyanin’s stabilityat pH=2.0,3.6and7.4. At pH=2.0, the stability of anthocyanin is black rice bran>blueberry> purple heart sweet potato> purple cabbage> blackberry anthocyanins; Thestability under the conditions of pH=3.6is purple sweet potato> purple cabbage>black rice bran> blueberry> blackberry anthocyanins; At pH=7.4, the stability ofthe purple sweet potato is greater than the purple cabbage, following by blueberries,black rice, and blackberry is the most unstable.3. To strengthen the stability of the non-acylated anthocyanins, We addeddifferent phenolic acids to solution of black rice bran anthocyanins at pH=7.4.theresults show that ferulic acid, caffeic acid, syringic acid and gentisic can improvestability of black rice anthocyanins, and p-coumaric acid, hydroxybenzoic acid,sinapic acid and ascorbic acid, vanillic acid and protocatechuic acid reduce itsstability.4. We studied the antioxidant activities of the five different anthocyanins byDPPH, FRAP, ORAC and CAA. The results of DPPH and FRAP methods show thatthe antioxidant abilities: blackberry> black Rice> blueberries>purple sweet potato>purple cabbage. The ORAC values is opposite, and the decreasing order: purple sweetpotato, blueberries, purple cabbage, blackberries, black rice bran. The reason may bethat the stability of five anthocyanins has difference at pH=7.4. The result is acomprehensive embodiment of the anthocyanin stability and antioxidant. The CAAvalue is: blackberry> black Rice> blueberry> purple sweet potato> purple cabbage.the results reflect the ability of passing through membrane and cellular antioxidantactivity of anthocyanins.The structure of anthocyanin is complex, and the commercialization of pureanthocyanins product is not much. Chemical synthesis has certain difficulty becauseof its stability. And pure anthocyanins products by extracting are limited.So studingvarious aspects through different structure from pure product of anthocyanins isdifficult. This topic of the paper from different raw materials has its own structuralcharacteristics. We can compare them with the stability and oxidation resistancethrough the analysis of different anthocyanins extract’s structural features. The studycan be for our in-depth study of anthocyanins structure-activity relationships. This research reveals the relationship of physiological activity, stability and structure ofanthocyanin, and provides the basic data for the development, utilization and deepprocessing of anthocyanins in the field of food industry.