Research Of The Rheological And Emulsification Properties Of Artemisia Sphaerocephala Krasch Polysaccharide

The Artemisia sphaerocephala Krasch Polysaccharide (ASKP) is rich in resources, atraditional Chinese medicine and food additive, has been reported to have bio-functionalproperty, thickening property and reducing interfacial tension property, it will be more andmore important to research the emulsification property of ASKP as a potential natural plantpolysaccharides emulsifier without security risks. In this work, ASKP was extracted from theouter layer of the Artemisia sphaerocephala Krasch seeds, the high/low molecular weightfraction (60P/60S), the ASKP with protein removed (ASKPE) and the ASKP treated bymaillard reaction (ASKPM), this four polysaccharides were obtained after a series ofprocessing to ASKP (including separation, purification and modification). Preparing emulsionunder the same conditions (the emulsifier is ASKP,60P,60S, ASKPE, ASKPM, gum arabic(GA) and gum ghatti (GG), respectively, the oil phase is medium-chain triglycerides (MCT)),then research the droplets size (D3,2: the sauter mean diameter; D4,3: the De Brouckere meandiameter) and distribution, Zeta potential, the partial distribution image and the time stabilityof emulsion, etc. Study about the emulsifications of ASKP and other fractions, in order toprovide experimental support and theoretical support for the development of a new naturalplant polysaccharide emulsifier.The main results are as follows:(1)The protein content of ASKP,60P,60S is3.723%、3.712%、0.409%, respectively, islow compared with the previously mentioned report. The intrinsic viscosity of ASKP,60P,60S is2.379L/g,4.106L/g,0.126L/g, respectively. The shear rate makes no influence to theapparent viscosity (positively correlated with the polysaccharide solution concentration,decreased with increasing temperature.) of ASKP and60P, while the apparent viscosity of60Sdecreased slightly with increasing shear rate. The interfacial tension of ASKP,60P and60Swere obviously less than GA in the same conditions, and60S is the most significant thanothers.(2) The d3,2and d4,3(were both0.832μm) and Zeta potential (-54.3mV) of the emulsion droplets were minimum when the concentration of ASKP is1.2%(w/w), MCT is5%(w/w).(3)The partial size distribution of fresh ASKP emulsion, mass concentration of ASKPand MCT is1.2%,5%respectively, present a standard normal distribution and concentrated.ASKP shows excellent emulsifying activity compared with commonly used natural emulsifierand thickener (GG and GA) when the concentration of polysaccharide is low. But theemulsion particle size distribution ranged gradually widened with the extension of storagetime, the peak decreased obviously, the distribution curve moved in the direction of largerparticles. The particle distribution image proves the oil droplets became larger and began tocoalescence after the emulsion storage for7d at room temperature. The particle size and Zetapotential increased to8.625μm、-40.1mV accordingly. It became easier and easier to coalesceafter the repulsion between oil droplets decreased with the increasing Zeta potential.(4) The results showed that ASKP has good emulsifying activity, the activity decreasedwith the removal of protein and increased slightly after maillard reaction. The emulsifyingactivity of ASKP was excellent at low concentration, but the emulsifying stability was poorercompared to GA and GG.