Study On Inclusion And Application Of Chlorogenic Acid By ?-cyclodextrins

Chlorogenic acid(CGA)is a polyphenol commonly existed in fruits and vegetables with a variety of bioactivities.To increase its stability and potential broader industrial application,CGA/cyclodextrins(CDs)complexes were prepared using ?-cyclodextrin(p-CD)and its derivative(2-hydroxypropyl)-?-cyclodextrin(2-HP-?-CD).Their inclusion complexation behavior and characterization were investigated by FT-IR,XRD,SEM,DSC and 1H NMR spectroscopy.The morphologic and spectral studies indicated the formation of inclusion complexes.Moreover,spatial arrangements of inclusion complexes were proposed based on 1H NMR results.The effects of solubilization of HP-?-CD to CGA were studied by phase-solubility method.In addition,the CGA/CD complexes were added in grape juice to explore the potential on the preservation of anthocyanin and color quality.The main research contents and the results are as follows:(1)The inclusion rate of CGA-CDs complex by solution mixing method was better than grinding or ultrasonic.In addition,the inclusion effect of HP-?-CD(64.2%)were better than ?-CD(48.6%).(2)The inclusion method has been optimized based on the analysis of single-factor tests and by orthogonal experiment.The optimum inclusion conditions are as follows:1:1 of molar ratio,35? of reaction temperature,and 3 h of reaction time.The inclusion rate of ?-CD and HP-?-CD under this condition was 49.1%,74.5%,respectively.(3)Their inclusion complexation behavior and characterization were investigated by FT-IR,XRD,SEM,and 1H NMR spectroscopy.The morphologic and spectral studies indicated the formation of inclusion complexes.By comparing the chemical shifts,it was noted that CGA might have been entered in the cavity of CDs from the wider rim.(4)The results of phase-solubility method showed that HP-?-CD has effect of solubilization on CGA,and the solubility of CGA is linearly increased with the increase of HP-?-CD concentration.It has also been preliminarily proved the possibility of 1:1 inclusion formation of CGA and HP-?-CD.The complex constant Kf is 2130.0 L·mol-1.(5)Stability of CGA in inclusion complexes under pH,temperature and light was investigated.Results showed the stability of the complexes improved compared with the CGA without inclusion,and the CGA-HP-?-CD complexes showed the highest stability.The antioxidant activities of the complexes were improved compared with the CGA without inclusion,and the CGA-HP-?-CD complexes showed the highest antioxidant activity.(6)Results showed that the degradation of anthocyanins was reduced when CGA and CGA/CDs inclusions were added in grape juice due to copigmentation effect,and their copigmentation strength showed in an order of CGA/HP-?-CD complex>CGA/?-CD complex>free CGA.