Nano-silver-containing polyvinyl alcohol composite film for grape fresh-keeping

Nano-composite film possesses antibacterial properties of nanomaterials and preservation performance of food packaging film. The goal of this work was to explore the potential application of nano-silver-containing polyvinyl alcohol (PVA) composite film in grape fresh-keeping. Mechanical properties, transparency, barrier performance and antibacterial activity of Nano-silver-containing PVA film were tested and results showed that the antibacterial zone diameter of nano-silver on Aspergillus niger was 14.4 mm, with minimum bactericidal concentration of 75 ppm. The PVA antibacterial membrane effectively revealed antibacterial properties. Moreover, the decreased mechanical properties and transparency enhanced barrier performance of antibacterial membrane compared with PVA film. For comparison, the fresh-keeping effects of non-packaging film, commercial cling wrap and nano-silver-containing PVA film on sensory score, mass loss rate, decay rate, Ascorbic Acid (Vc) content and titratable acid content were also studied. Results indicated that the PVA antibacterial membrane significantly effectively avoided sensory score, water, decay, Ascorbic Acid (Vc) and titratable acid in grapes during storage, and had a remarkable effect in prolonging grapes' shelf life due to its breathability and antibacterial activity.