Preparation and characterization of improved gelatin films incorporating hemp and sage oils

The aim of the study is to prepare and characterize gelatin films incorporating hemp and sage oil, to obtain an edible film which combines both food preservation and nutritional properties. Gelatin film-forming solutions were investigated in terms of wettability in relation to different foodstuff and their antimicrobial properties against Escherichia coli, Staphylococcus aureus, Listeria innocua, Saccharomyces cerevisiae and Penicillium expansum. The gelatin films were evaluated for their water vapor permeability, solubility in food simulants, moisture content, thickness and light barrier property. The steeper decrease in contact angles, surface tension and spreading coefficients was displayed by the sage oil-gelatin film solution and the mildest by the hemp oil-gelatin film solution. The most suitable foodstuffs to be coated in sage/hemp oil-gelatin films seem to be Golden Apple, pork meat and processed cheese, whereas the least suitable appear to be garlic, red bell pepper and cauliflower. Hemp oil has moderate antimicrobial action, while the sage oil displays a strong inhibition. Additive effect is expressed in case of all gelatin film solutions containing sage and hemp oils combinations. The sage oil-gelatin film displays the lowest water vapor permeability and moisture content, while the hemp oil-gelatin film results in the lowest thickness and highest light barrier property. Hemp oil-gelatin film is more soluble than the sage oil-gelatin film. Varying degrees in the investigated parameters can be noticed in cases of oils mixtures-gelatin films depending by the dominant oil. (C) 2015 Elsevier Ltd. All rights reserved.