title: Characterization and evaluation of the Ag+-loaded soy protein isolate-based bactericidal film-forming dispersion and films.
abstract: This study aims to prepare bactericidal films developed from soy protein isolate (SPI) based film-forming dispersions (FFDs) for use in the food and medical fields. The FFD and films were prepared after the incorporation of different concentrations of AgNO₃ as a bactericidal agent. The transparency, tensile strength, and antimicrobial features were evaluated. Structural characterizations were also performed by Fourier transform infrared spectroscopy, scanning electron microscope, and atomic force microscopy analysis. Results showed that the opacity of these FFD was greatly decreased after the incorporation of AgNO₃. The SPI-5 film has the largest tensile strength (P < 0.05) compared with that of the other ones. Micro structural imaging analysis showed an increase in the surface irregularities with the addition of AgNO₃. The minimum inhibitory concentration of AgNO₃ was 336 μg/mL FFD for both Escherichia coli ATCC 25923 and Staphylococcus aureus ATCC 25922. The SPI-AgNO₃ films developed from the FFD with the minimal AgNO₃ concentration at 336 μg/mL FFD also showed bactericidal effects for both the strains. These results may prove promising for the use of SPI-AgNO₃ films in the food or medical industries.
  
  
  CONCLUSIONS
  The films prepared in this study are biodegradable and will be used in medical and food fields.
authors.affiliation: College of Life Science, Key Laboratory of Microbiology, College of Life Science, Heilongjiang Univ., Harbin 150080, PR China.
authors.forename: Qingshen
authors.initials: Q
authors.lastname: Sun
authors.forename: Xiaodi
authors.initials: X
authors.lastname: Li
authors.forename: Pu
authors.initials: P
authors.lastname: Wang
authors.forename: Yiyang
authors.initials: Y
authors.lastname: Du
authors.forename: Dequan
authors.initials: D
authors.lastname: Han
authors.forename: Fengjiao
authors.initials: F
authors.lastname: Wang
authors.forename: Xumei
authors.initials: X
authors.lastname: Liu
authors.forename: Pengfei
authors.initials: P
authors.lastname: Li
authors.forename: Honggang
authors.initials: H
authors.lastname: Fu
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000494:pharmacology; D055598:Chemical Phenomena; D003102:Colloids; D004926:Escherichia coli / Q000187:drug effects / Q000254:growth & development; D005516:Food Microbiology; D018857:Food Packaging; D005517:Foodborne Diseases / Q000517:prevention & control; D055595:Mechanical Phenomena; D008826:Microbial Sensitivity Tests; D018625:Microscopy, Atomic Force; D008855:Microscopy, Electron, Scanning; D009994:Osmolar Concentration; D011108:Polymers / Q000737:chemistry* / Q000378:metabolism; D012835:Silver Nitrate / Q000737:chemistry* / Q000494:pharmacology; D030262:Soybean Proteins / Q000737:chemistry* / Q000378:metabolism / Q000648:ultrastructure; D017550:Spectroscopy, Fourier Transform Infrared; D013211:Staphylococcus aureus / Q000187:drug effects / Q000254:growth & development; D013499:Surface Properties; D013718:Tensile Strength
chemical_list: D000900:Anti-Bacterial Agents; D003102:Colloids; D011108:Polymers; D030262:Soybean Proteins; D012835:Silver Nitrate