| This paper mainly studied on the composition of black rice anthocyanins,antioxidant effect in vitro,proliferative effect of probiotics and inhibitory effect pathogenic bacteria and micro-encapsulation.Firstly,black rice as raw material,anthocyanins were preparated and then the anthocyanins composition was analyzed by HPLC-MS/MS.Secondly,the antioxidant,proliferation of probiotics and the inhibition of spoilage were researched.Finally,because the structure of anthocyanin was susceptible to pH,temperature,metal ions and other factors,the black rice anthocyanins was microencapsulated to improve the stability.The main contents and results are as follows:1.The anthocyanins composition was analyzed.The anthocyanins composition was analyzed by HPLC-MS/MS.There were six compositions including cyanmeline-3,5-diblucoside,cyanidin-fenugin-hexoside,cyanidin-3-glucoside?81.99%?,cyanidin-3-rutanoside,paeoniflorin-3-glucoside and paeoniflorin-3-rutanoside.2.The antioxidant activity of anthocyanins and cyanidin-3-glucoside was studied.The DPPH radicals,hydroxyl radicals,superoxide anion,anti-lipid peroxidation effect and the total reducing power were determined by DPPH method,salicylic acid method,pyrogallol method,thiobarbituric acid method and Prussian blue method,respectively.Vc was used as positive control during the course of the tests.The results showed that the clearance rate of DPPH·,·OH and O2-·,anti-lipid peroxidation effect and the total reducing power of black rice anthocyanins were 98.85?79.94?79.66 and 72.58%,0.271,respectively.Cyanidin-3-glucoside was 98.98,90.57,81.92 and 75.54%,0.359,respectively.Vc was 98.98,99.76,98.51 and 90.93%,0.580.At the same concentration,the scavenging ability of DPPH·,·OH and O2-·,anti-lipid oxidative ability and reducing power of cyanidin-3-glucoside were better than those of anthocyanins.3.The proliferative effect of anthocyanins and cyanidin-3-glucoside on probiotics was studied.In the corresponding medium,different concentrations of the anthocyanins and cyanidin-3-glucoside and probiotics were added,then cultivated without O2 in vitro.After incubation for 36 h,the bacterial number and pH of the medium were determined.The results showed that both the anthocyanins and cyanidin-3-glucoside could stimulate the proliferation of B.infantis,B.bifidum,B.adolescentis and L.acidophilus significantly.The optimal proliferative concentrations of the anthocyanins against B.infantis,B.adolescentis,B.bifidum and L.acidophilus were 2.0,1.0,1.0 and 1.5 mg/mL,respectively;For cyanidin-3-glucose,the best proliferative concentrations of the four strains were 1.0,1.0,1.0 and 1.5 mg/mL,respectively.4.The inhibitory effect of anthocyanins and cyanidin-3-glucoside on pathogens was studied.The antibacterial activity of the two samples was studied by the filter paper method and the diameter of the inhibition zone was the evaluation standard.The results showed that both of them could inhibite the two pathogens and the inhibitory effect was enhanced with the increase of the sample concentration.At the same concentration,the inhibition of Salmonella was stronger than that of S.aureus.5.The anthocyanins were microcapsulated.The anthocyanins were microencapsulated by sharp hole-coagulation bath method and ?-cyclodextrin??-CD?inclusion method.On the basis of single factor tests,an orthogonal experiment and verification tests were carried out to determine the optimum conditions of the two methods.The optimum conditions of sharp hole-coagulation bath method were sodium alginate 2.00%,chitosan2.25%,wall core ratio 16:1 and needle diameter 0.55 mm.At the condition,the embedding rate of the anthocyanin was 84.17%.The optimum conditions of ?-CD inclusion method was stirring time 1.75 h,?-CD addition 3.0%,emulsifier amount 1.75% and stirring speed 660 r/min.At the condition,the embedding rate of the anthocyanin was 26.87%.6.The releasing degree of anthocyanins microcapsuled in stomach and intestinal simulation solution and effect of microencapsulation on the stability of anthocyanin were studied.The results showed that the anthocyanins microcapsuled could be maintained in the stomach simulation solution for 4.0 h,and then released slowly in the intestinal simulation solution.Microcapsulation could increase the anthocyanin content in metal ions(Ba2+,Cu2+,Zn2+,Al3+ and Mg2+)and oxidants?H2O2?.However,Microcapsulation could not improve the effects of high temperature and pH on the stability of the anthocyanins significantly.At the same time,microencapsulation also could prevent the effect of some color protection agents on the anthocyanins. |
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