Improvement Of Emulsifying And Gelation Properties Of Sugar Beet Pectin Based On Covalent Crosslinking

Sugar beet pectin is a kind of acid anionic polysaccharide extracted from beet pulp.It has good emulsifying properties which could be attributed to the abundant lateral chains composed of neutral sugars,high acetyl and protein contents.But the emulsifying stability of SBP should be improved due to the low adsorption amount on the water-oil interface.In addition,the small molecular weight and high acetyl content contributited to its poor gelation properties,including mechanical and water holding capacities which has limited its wide utilization.In the research,sugar beet pectin was adopted as the research object and the study tried to find the solutions to improve its emulsifying and gelation properties by the approach of covalent crosslinking(Maillard reaction and laccase catalysis)between proteins and sugar beet pectins.Main research and conclusions were as follows:1.Pectins extracted by different conditions and from different origins of beet pulp varied in protein,ferulic acid and amino acid contents.High protein and ferulic acid contents could be obtained under high temperature and low pH.Furthermore,sugar beet pectin showed better emulsifying activity and stabiliy than BSA and GA.2.The impact of intrinsic proteins to the emulsifying properties of sugar beet pectins was studied.Pepsin was adopted to remove proteins from the lateral chains of SBP.The droplet size of deproteinized SBP-emulsion increased drastically under thermal treatment,strong acidic and ionic conditions.While the emulsifying properties of deproteinized SBP turned off after the addition of BSA by electrostatic complex and Maillard reaction.Furthermore the emulsifying properties of Maillard reaction products were even better than the original SBP.3.To improve the emulsifying properties of sugar beet pectin,sodium caseinate(SC),whey isolate protein(WPI)and bovine serum albumin(BSA)were complexed with sugar beet pectin respectively for the preparation of emulsion.The results showed that the the combination processes of these complexes between different proteins with SBPs were generally the same.Among of which,SC-SBP complex was the most sensitive to pH values and WPI-SBP showed the best emulsifying properties due to the synergistic effect of different proteins.4.On the basis of the optimum conditions for electrostatic complex between bovine serum album and sugar beet pectins,covalent crosslinking(including Maillard reaction and laacase catalysis)was adopted to further improve the emulsifying properties.The results showed that both of the covalent conjugates showed better emulsifying properties than SBP or BSA individual as well as their electrostatic complex.Furthermore Maillard reaction products showed the best emulsifying properties.5.SPI-SBP double network gelation was established by heating and laccase catalysis process.The textural properties,water holding capacity,internal structure compactness and smoothness of the double network gelation were better than single network gelation.Increasement in protein content mainly improved the elasticity of the gelation,while SBP mainly increased the hardness.