Isolating And Charactering Polyphenols And Polysaccharides From Lotus Root For The Preparation Of Blended Liposomes

As a kind of aquatic vegetables with the highest yield,Nelumbo nucifera Gaertn.is not only rich in nutrients,but also contains various functional ingredients such as polyphenols and polysaccharides,which confers various effects on immune conditioning,lipid lowering,blood pressure lowering,blood sugar lowering,etc.In order to explore the development and utilization of the main functional components of lotus root,the polyphenols and polysaccharides of lotus root were extracted and their composition and structure characteristics were clarified.The polysaccharidepolyphenol complex liposome was further developed and its stability was investigated.The main research contents and results are as follows.(1)Macroporous resin purification and composition analysis of lotus root polyphenols.Ultrasonic assisted-solvent extraction was used to prepare crude polyphenols from lotus root.The adsorption and resolution of polyphenols were used to screen out HPD-100 from five different macroporous resins for purification of lotus root polyphenols.Polyphenols,systematically investigated the influence of adsorption and analytical factors on the separation effect,and established the optimal conditions for orthogonal test optimization and establishment of HPD-100 macroporous resin separation and purification: adsorption time 1h,adsorption temperature 35 °C,solution pH value 3,The concentration of ethanol solution was 70% and the resolution time was 1 hour.Under this condition,the polyphenol adsorption rate was 93.14% and the resolution was 74.21%.After purification,the crude polyphenol extract of lotus root increased from 26.39% to 58.21%.The polyphenols of lotus root are mainly composed of gallocatechin,epigallocatechin gallate,catechin and unknown compound with a molecular weight of about 204,and the composition before and after purification does not change.(2)Isolation,Purification and Structural Analysis of Polysaccharide from Lotus Root.The lotus root polysaccharides were prepared by hot water extraction and ethanol step-by-step alcohol precipitation.The molecular weight distribution of the polysaccharides of lotus root was relatively concentrated(about 17.91 kDa)by GPC analysis.The monosaccharide composition determined by pre-column derivatization HPLC method showed that the polysaccharides of lotus root were mainly composed of mannose,rhamnose,glucuronic acid,galacturonic acid,glucose,galactose and arabinose at a molar ratio of 0.19:0.14:0.08:0.17 :6.49:1.00: 0.16 component.The IR spectra of lotus root polysaccharides all exhibited common polysaccharide and protein signature bands,and the UV spectra of lotus root polysaccharides were not specific.(3)Preparation and stability evaluation of lotus root polyphenol-polysaccharide complex liposome: The entrapment efficiency of lotus root polyphenols and polysaccharides was used as an index,and composite liposomes were prepared by reverse evaporation to examine the concentration of polyphenols,polysaccharide concentration,The effect of phospholipid sterol ratio,ultrasonic time and high shear speed on liposome encapsulation was further confirmed by orthogonal test: the phospholipid sterol ratio 1:4,lotus root polyphenol concentration 15 mg/mL,lotus root The polysaccharide concentration was 1.5 mg/mL,the ultrasonic time was 6 min,and the high-speed shear rate was 8000 r/min.Under these conditions,the resulting plastid potential was-38.7 mv,the particle size was 123.01 nm,the polyphenol encapsulation efficiency was 72.36%,polysaccharide encapsulation.The rate is 15.66%.The effect of different storage conditions on the stability of polysaccharide-polyphenol complex liposomes was investigated.The results showed that the storage form and temperature had significant effects on the stability of the composite liposomes: the stability of the liposomes after lyophilization was more stable than that of the liquid liposomes;the stability of the stored liposomes was stable at 4°C and 25°C,low temperatures favor the storage of liposomes.After being stored at 4 °C for 20 days,the stability was similar to that of liposomes stored at 4°C for 24 hours.The entrapment efficiency of the polyphenols was about 65%,and the entrapment efficiency of the polysaccharides was about 11%.A series of preparation techniques for the preparation of lotus root polyphenols,polysaccharides and their composite liposomes were established.The results can provide references for the development of functional components of lotus root and provide new ideas for deep processing of lotus root.