Study Of The Properties Of Concentrated Soy Protein Emulsions And Its Relationship With The Structure

Oil-in-water concentrated emulsion systems containing soy proteinconcentrate(SPC), functional soy protein concentrate (FSPC), soy protein isolate(SPI) and commercial soy protein isolate (CSPI) were characterised by looking atrheological properties and microstructure. nitrogen solubility in differentsolvent, surface hydrophobicity, molecular weight distribution, intrinsicviscosity, differential spectrophotometric method and DSC were also used to probeinto the characters including molecular interactions ,molecular weightdistribution and conformational stabilities of different soy protein and itsrelationship with the concentrated emulsion systems. All emulsion systemsexhibited pseudoplastic behavior, and viscosity of either FSPC or CSPI emulsionsystem was higher than that of SPI. Elastic moduli of each emulsion system was alsodifferent and FSPC and FSPI resulted in emulsions with more solid properties.Microstructure of different emulsion system observed by SEM indicated that networkof protein and flocculated droplets in such concentrated emulsions. The resultsof DSC and differential spectrophotometric method indicated that in contrast withSPC and SPI, FSPC and CSPI were highly denaturalized. Molecular interactions wereimportant to the formability and stability of the concentrated emulsion systems.Soy protein with strong covalent bond like SPC was not easy to outspread in system,but exist of non-covalent bond was good for the flocculation, even forming gelemulsion. The results of gel filtration and intrinsic viscosity show that molecularweight of CSPI was greater than the others, and SPC was the smallest. It was foundthat the concentrated emulsion systems improved with the increasing molecularweight and flexibility.