Determination some physical and chemical properties of gelatin-chitosan films enriched with different ratios of lemon oil

In this study, film solubility, film thickness, tensile strength and elongation at break, colour values (CIE L*, a*, b*), light transmittance, amount of total phenolic compound, antioxidant activity values (DPPH, ABTS, metal chelating activity) of gelatin-chitosan films enriched with different ratios of lemon oil (0.25%-0.50%-0.75%-1%) and gelatine-chitosan (40%-60%) based film without lemon oil (control) were determined. Scanning electron microscope (SEM) images of gelatin-chitosan based films containing lemon oil were obtained. Fourier transform infrared spectroscopy (FTIR) analysis had been made. Lemon oil's main volatile components were determined with gas chromatography-mass spectrometer (GC-MS). Ascorbic acid contents of the film samples were determined with high performance liquid chromatography (HPLC). Total phenolic compound contents of film samples enriched with lemon oil were found between with 5.12 mg/kg and 276 mg/kg. As a result, it was determined that with increased lemon oil ratio, total phenolic compound content, antioxidant activity and ascorbic acid contents were increased. Considering the effect of lemon oil on consumers preference, optimum lemon oil ratio has been determined as 0.75%. Apple slices were coated with gelatin-chitosan based film; gelatin-chitosan based films with 0.75% lemon oil and some samples were not coated. All these samples were stored at +4°C in refrigerator and their pH values and total mesophilic aerobic bacteria count were determined during storage period (zero, fifth, seventh day). Results were evaluated statistically with SPSS 24.0 (P<0.05).