Study On The Extraction,Synthesis,separation Techniques And Physicochemical Properties Of Bioactive Components In Cocoa And Maca

In this study,the functional constituents in cocoa beans and maca were extracted,separated,synthesized and purified.The physicochemical properties of the functional constituents were also studied.This research has developed extraction methods for crude cocoa beans and maca and HPLC method for analysis.Experimental data were correlated using equations to calculate the physicochemical parameters of the constituents.Some solutions were given in the process of extraction,separation,purification and storeage.The thesis is composed of five chapters:Chapter one is the introductory part.The development situation of natural products is briefly introduced.This chapter concludes the extraction,separation,analysis and identification technique used in the natural product research.The related literatures published recent years were reviewed.Chapter two develops an efficient method for the decaffeination and enrichment of the polyphenols from cocoa husks extracts.LX-17 was selected for the exploration of optimal processing parameters from eight kinds of macroporous resins.The optimum parameters for separation were as follow:6.0 mg/mL cocoa extracts,pH 2.0,25 ℃column temperature,flow rates of adsorption and desorption 1.6 BV/h and ethanol-water(20:80,50:50,95:5,v/v)solutions in the gradient elution.In the scale-up separation,2 kg of cocoa husks were extracted in 20 L 50%ethanol solutions,separated on 3 L LX-17 resins and yielded 34.99 g cocoa polyphenols.This method significantly increased the total polyphenol contents from 2.23%to 62.87%with a recovery yield of 78.57%.The solubility of theobromine,theophylline and caffeine in water,methanol,ethanol,n-propanol,ethyl acetate and acetone(288.15 K to 328.25 K,atmosphere pressure)was determined in chapter three.The solubility of the studied alkaloids incteased as the temperature went up.Abelblat equation and UNIQUAC equation were used to correlate the solubility data.The crystal habits were characterized using SEM and PXRD.The thermodynamics properties were studied using DSC and TGA.In chapter four,macamides,N-benzyl-(9Z,12Z,15Z)-octadecatrienamide,N-benzyl-(9Z,12Z)-octadecadienamide,N-benzylhexadecanamide and N-benzyl-9Z-octadecenamide were isolated from crude Maca extracts using high-speed countercurrent chromatography(HSCCC).Also,thses four compouds were synthsised and purified.The synthesis and HSCCC separation methods were compared.The four macamides were identified by NMR,UV,HRMS and IR spectra.The thermal stability and autoxidative kinetics for N-benzyl-(9Z,12Z,15Z)-octadecatrienamide and N-benzyl-(9Z,12Z)-octadecadienamide in the air were also studied at various temperatures and the apparent activation energy was calculated 28.4 kJ/mol and 29.9 kJ/mol,respectively.The purity of the isolated macamides was up to 98%and the amount was enough for application as a reference substance.Chapter five is summary and prospect which summarizes the research content and the highlights in this study.Also,the shorcomings in the research process and some suggestions for future work were given.