DETERMINATION OF THE EFFECTS OF COATING WITH SODIUM ALGINATE FILM CONTAINING THYME ESSENTIAL OIL ON THE SHELF LIFE OF OLIVES
Project no. 22112 · Status: Kapanmış · 2020
Summary
In recent years, the increasing demands of consumers for natural and high nutritional value foods that do not contain additives with natural preservation techniques, as well as the serious environmental problems caused by petrochemical-based plastic packaging wastes have caused studies to focus on edible film and coating technology. In this study, the possibilities of using edible film coatings as a preservation technique were investigated in Hurma olives that are consumed raw and have a short shelf life. For this purpose, films prepared from sodium alginate with three different concentrations of thyme essential oil (0,5%, 1%, 1,5% v/v) were produced as edible film. Solubility, thickness, light transmittance, elongation at break and tensile strength, color, total amount of phenolic substance, antioxidant activity and scanning electron microscope imaging (SEM) analyses were performed in each prepared film group. When the film analysis results were evaluated, it was concluded that the addition of thyme essential oil, a natural additive at a concentration of 1% (v/v), improved the physical and chemical properties of sodium alginate film better compared to other groups. Control (uncoated) olives, olives coated only with sodium alginate and sodium alginate film with the addition of 1% (v/v) thyme essential oil stored in polyethylene terephthalate (PET) package. The other olive group was again covered only with sodium alginate film solution and kept in vacuum packaging. Moisture, pH, water activity, color, hardness, acidity, bitterness, total amount of phenolic substance, antioxidant activity, amount of oleuropein, total yeast-mold count and sensory evaluation analyses were applied to olive samples. Storage conditions of olives were determined as 42 days at 4 ?. Physicochemical analysis were performed during storage on the days of 0., 7., 14., 28., 35., 42. Microbiological and sensory analyses were carried out on the days of 0., 14., and 42. According to the results of the analysis, it was observed that olives that were applied to the coating can be stored in a safer and higher quality and increase their shelf life. Especially thyme oil containing sodium alginate coated olives gave better quality results.