Active Packaging System Based on Ag/TiO₂ Nanocomposite Used for Extending the Shelf Life of Bread. Chemical and Microbiological Investigations

Abstract

This study was carried out to assess the shelf life and microbiological safety of wheat bread during storage in a packaging system made of Ag/TiO 2 nanocomposite (Ag/TiO 2 ‐P) in comparison with bread packed in high density polyethylene (HDP‐P) and bread not subject to packaging (CS). The Ag/TiO 2 nanocomposite was prepared by sol–gel procedure, and its morphostructural characterization was performed by X‐ray diffraction, Fourier transform infrared spectroscopy and transmission electron microscopy. The Ag/TiO 2 ‐P was prepared via inclusion of nanocomposite between the polyethylene layers to avoid bread–nanocomposite contact. Chemical and microbial stability of bread expressed in terms of total fat, protein, sugar, lipid hydroperoxides and yeasts, moulds, and Bacillus subtilis and Bacillus cereus counts, respectively, was monitored for 6 days. Experimental data indicate that Ag/TiO 2 ‐P considerably extends the shelf life and microbiological safety of bread in comparison with HDP‐P and CS. A possible mechanism involved in the preservation of the bread is hypothesized. Copyright © 2014 John Wiley & Sons, Ltd.