Antibacterial activity of gelatin/copper (II)-exchanged montmorillonite films. (March 2017)

• Record Type: Journal Article
• Authors: Martucci, Josefa F.; Ruseckaite, Roxana A.
• Is Part Of: Food hydrocolloids. Volume 64(2017)
• Page Start: 70
• Page End: 77
• Publication Date: 2017-03
• Subjects: Bovine gelatin -- Cupric ions -- Montmorillonite -- Nanocomposite -- Active film -- Antimicrobial activity; Hydrocolloids -- Periodicals; Food additives -- Periodicals; Colloïdes -- Périodiques; Aliments -- Additifs -- Périodiques; Colloids; Food additives; Periodicals; Electronic journals; 664.06
• DOI: 10.1016/j.foodhyd.2016.10.030
• Languages: English
• ISSNs: 0268-005X

Abstract

Abstract: Cu (II) - exchanged montmorillonite (Cu 2+ MMt) was prepared, characterized and introduced into a bovine gelatin (Ge) matrix via a dissolution-intercalation method to get antibacterial nanocomposite films. The maximum amount of exchanged cation did not exceed the cation exchange capacity of the pristine montmorillonite (Na + MMt), as assessed by energy dispersive X-ray (EDX) spectroscopy. Cu 2+ MMt showed antibacterial activity in vitro against Escherichia coli O157:H7 (Gram-negative) and Listeria monocytogenes (Gram-positive) as revealed by the agar disc-diffusion assay. The dispersion of clays in Ge films was monitored by X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). Blending gelatin with 5% w/w of clay increased the tensile strength of the nanocomposite films in around 280% while the elongation at break and the water vapor permeability decreased in about 42 and 30%, respectively, regardless of the cation in clay. The Ge/Cu 2+ MMt film exhibited antibacterial effectiveness against both pathogens tested under the same conditions, demonstrating a stronger effect on L. monocytogenes than on E. coli O157:H7, since the cell wall of the latter differs significantly and such difference could influence their vulnerability and response to the active films. Therefore, the incorporation of low clay levels as a vehicle for copper ions into gelatin matrix has demonstrated to be a good method for developing functional materials that can be potentially applied to the design of food contact items. Graphical abstract: Highlights: Cu 2+ MMt was obtained by ion exchange from acid activated Na + MMt. Cu 2+ MMt showed strong activity against E. coli and L. monocytogenes . Inclusion of 5% w/w clay enhanced tensile strength and water vapor barrier of gelatin films. Significant antibacterial property was observed for Ge/Cu 2+ MMt films.