Novel bionanocomposite materials used for packaging skimmed milk acid coagulated cheese (Karish).

Bionanocomposites have attracted a tremendous level of consideration as alternatives for a broad group of commercial materials based on petroleum-derived compounds and used for coating cheese. Sustainable, economical and environmentally compatible materials based on chitosan (CS), poly vinyl alcohol (PVA), glycerol (Gy) and titanium dioxide nanoparticles (TiO ₂ -NPs) were prepared. Moreover, the prepared bionanocomposites (CS/PVA/Gy/TiO ₂ -NPs) were characterized using XRD, SEM, TEM, WVTR and mechanical strength. The developed CS/PVA/Gy/TiO ₂ -NPs bionanocomposites exhibited homogeneous, compact morphological features and enhanced mechanical and barrier properties. Also, the prepared bionanocomposite exhibited variable inhibitory effects against several pathogenic bacteria and fungi. Karish was made and coated with the prepared bionanocomposite containing 1, 2 and 3% TiO ₂ -NPs, and cold stored. Changes in the weight losses, cheese composition, microbiological quality, textural parameters, and sensory properties were followed during storage for 25 days. Coated Karish cheese retained acceptable quality until the end of the storage period, while uncoated developed surface fungi growth and deteriorated quality after 15 days. Karish cheese coated with the bionanocomposite containing 3% TiO ₂ -NPs ranked the highest acceptability at the end of storage period.
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