title: Stability and antimicrobial property of soy protein/chitosan mixed emulsion at acidic condition.
abstract: To fabricate a soy protein emulsion with good storage stability against microorganisms, we investigated the stability and antimicrobial activity of a β-conglycinin (7S) and chitosan (CS) mixed emulsion at acidic pHs. Results of droplet size and microstructure showed that 7S/CS mixed emulsions were stable at acidic pHs while the 7S emulsion was not. As for the storage test, results showed that the 7S/CS mixed emulsion displayed an significantly (p < 0.05) improved storage stability than the control both under un-inoculated and inoculated conditions at 20 °C because of the presence of chitosan. A well diffusion assay showed that the 7S/CS mixed emulsion provided better inhibition against Escherichia coli and the minimum mixing ratio of the chitosan content, of 0.25 mg mL(-1), adequately inhibited the bacteria used in this research. Moreover, the aerobic plate count analysis indicated that the 7S/CS mixed emulsion, compared to the control, effectively inhibited the growth of microorganisms. This inhibition was believed to be independent of the CS/7S mixing ratio. The results in this paper demonstrate that the growth of microorganisms dramatically accelerated the destabilization of the stable 7S emulsion and the fabrication of 7S/CS mixed emulsion could increase the acidic stability and antimicrobial activity in order to extend shelf-life.
authors.affiliation: Research and Development Center of Food Proteins, College of Light Industry and Food, South China University of Technology, Guangzhou 510640, PR China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Yuan
authors.forename: Zhili
authors.initials: Z
authors.lastname: Wan
authors.forename: Shouwei
authors.initials: S
authors.lastname: Yin
authors.forename: Xiaoquan
authors.initials: X
authors.lastname: Yang
mesh_terms: D000890:Anti-Infective Agents / Q000737:chemistry*; D052179:Antigens, Plant / Q000737:chemistry*; D048271:Chitosan / Q000737:chemistry*; D015169:Colony Count, Microbial; D004355:Drug Stability; D004655:Emulsions / Q000737:chemistry*; D004926:Escherichia coli / Q000187:drug effects / Q000254:growth & development; D005916:Globulins / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D018613:Microscopy, Confocal; D055314:Seed Storage Proteins / Q000737:chemistry*; D030262:Soybean Proteins / Q000737:chemistry*
chemical_list: D000890:Anti-Infective Agents; D052179:Antigens, Plant; D004655:Emulsions; D005916:Globulins; D055314:Seed Storage Proteins; D030262:Soybean Proteins; C013894:beta-conglycinin protein, Glycine max; D048271:Chitosan