Effect of packaging in polyethylene-clay nanocomposite film on quality and storage life of sliced bread

Packaging is an effective way to decrease staling of bread and other bakery products. This study determined the effect of two types of polyethylene-clay nanocomposite film with thicknesses of 45 and 50 µm on the decrease in staling and increase in the shelf-life of sliced bread. Sliced bread was packed in polyethylene (control) or nanocomposite film and stored at 25°C for 10 d. The water content, hardness, thermal properties (melting enthalpy of ice and retrograde starch), and microbial stability of the bread samples were measured at 2 day intervals. Water retention was higher for samples packed in nanocomposite film. The melting enthalpy of ice measured by DSC was lower, but the melting enthalpy of starch was higher for the control, indicating that nanocomposite packaging delayed the staling of the bread samples. The growth of mold was high in all samples. The nanocomposite film could not control mold growth because of the higher moisture content inside this type of packaging. The nanocomposite film retarded staling of sliced bread; however, it did not control mold growth. The addition of anti-microbial agents to the nanocomposite film is required to take advantage of the increased preservation of freshness from this type of packaging.