Effect Of Different Preparation Conditions On Physical And Chemical Properties Of Sugar Beet Pectin And Its Application

As a natural food gum and functional additive,sugar beet pectin has good emulsifying properties.The extraction of pectin from sugar beet pulp could not only enhance the additional value of sugar industry and increase economic benefits,but also reduce the environmental pollutions.Due to its unique structural characteristics,sugar beet pectin has different functional characteristics and broad prospects for development in the pectin market compared with pectins from other sources.In this paper,the effects of different preparation conditions on the physicochemical properties of sugar beet pectin and the addition of sugar beet pectin on the peanut protein isolate mixed system were studied.It could understand the characteristics of sugar beet pectin and extend the application of sugar beet pectin in the food industry.The main results are as follows:1.Sugar beet pulp powders in different particle size were prepared by superfine and conventional grinding methods.The effect of grinding methods on the properties of sugar beet pulp powders were studied.The results showed that superfine grinding method could produce smaller and brighter powders compared to conventional grinding method.As particle size decreased,the bulk density,tap density,the angle of repose and angle of slide increased and the fluidity decreased.The water and oil binding capacities of the conventional grinding samples increased with the decreasing particle size.Differential scanning calorimetry analysis showed that the transition temperature and melting temperature decreased as the particle size decreased.According to the results of X-ray diffraction,the superfine grinding could destroy the crystal structure of the powder and reduce its crystallinity.2.The effect of particle size of sugar beet pulp powders on the extraction yield,composition and rheological properties of the pectin were investigated.The results showed that by decreasing the particle size of sugar beet pulp powders from 406.33 to 24.93 ?m,the extraction yield increased from 15.81%to 20.50%and galacturonic acid content increased greatly from 38.51%to 59.97%.As particle size of SBP increased,intrinsic viscosity([?]),viscosity-average molecular weight(Mv),apparent viscosity and activation energy of SBP pectin were significantly increased.All pectin samples showed a strong shear thinning behavior and the same linear viscoelastic properties.3.The effects of hot air drying,vacuum drying,freeze drying and spray drying on the rheological and emulsifying properties of sugar beet pectin were studied.Drying methods and conditions had no effect on the structure of sugar beet pectin,but affected the degree of esterification.The pectin prepared by spray dying had the highest degree of esterification and the pectin prepared by hot air dying had the lowest degree of esterification.The apparent viscosity of sugar beet pectin solutions decreased with increasing the temperature of vacuum drying.Spray drying could increase the dynamic viscoelastic pectin solution.The emulsifying activity index(EAI)of spray-dried samples increased with increasing drying temperature.4.Sugar beet pectin was modified by polygalacturonase,a-1,4 glycosidic bond in sugar beet pectin molecule was cut off by hydrolysis.The effect of modification conditions such as pH,temperature and polygalacturonase content on the apparent viscosity of sugar beet pectin was determined on-line with rheometer.The modification conditions were optimized,the reaction pH was 4.5,the reaction temperature was 60? and the polygalacturonase concentration was 150 U/mL.The emulsifying activity and stability of the polygalacturonase modified sugar beet pectin emulsion were improved under the optimal modified conditions and sugar beet pectin had good emulsifying activity and stability.5.The effects of sugar beet pectin on the rheological and emulsifying properties of the sugar beet pectin-peanut protein isolate mixed system were investigated based on the application of pectin in the polysaccharide-protein mixture system.The results showed that the addition of sugar beet pectin increased the apparent viscosity and activation energy of the mixed solution significantly.Low concentrations of sugar beet pectin(0.1,0.3%,w/v)inhibited the emulsifying properties of the peanut protein isolate emulsions in the mixed emulsions,while high concentration(? 0.5%,w/v)of sugar beet pectin enhanced the emulsifying activity and stability of the emulsion.The interaction of sugar beet pectin and peanut protein isolate changed the rheological and emulsifying properties of the mixed system.6.The non-linear rheological properties and microstructures of sugar beet pectin-peanut protein isolate mixed gels were investigated.The addition of sugar beet pectin increased the mixed gel strength,the mixed gels showed Type I strain-thinning network structure.The mixed gels changed from "soft gels"to "hard gels" at pectin concentrations of 1.0%,1.5%and 2.0%(w/w).The addition of sugar beet pectin increased the porosity of the mixed gels and the degree of chaos in the microstructures.The grinding methods had an effect on the properties of sugar beet pulp powders,which could had a significant effect on pectin extraction,galacturonic content and rheological properties.Drying methods have no obvious effect on pectin structure,but had an impact on the degree of esterification.The modification by polygalacturonase improved the emulsification and stability of sugar beet pectin emulsions.The addition of sugar beet pectin has changed the functional properties of the mixed system of pectin-peanut protein isolate.In summary,the results of this paper could provide theoretical basis and technical reference for the preparation and application of sugar beet pectin in the industry.