Developing composite ldpe packages for increasing the shelf lives of fresh fruit and vegetables

In this dissertation study, it is planned to give high ethylene/carbondioxide adsorption properties and suitable gas permeability properties by adding zeolite minerals to low density polyethylene (LDPE) based food packages which have widely use in packaging industry. Furthermore, it is also aimed to give antimicrobial properties by silver ions and anti-fogging properties by surfactants like glycol mono oleate. In line with this purpose; zeolite minerals were produced in additive masterbatch forms by surfactant additives like glycol mono oleate and antimicrobial additives including silver ions and twin-screw extruder. Packaging films with the dimensions of 260x370 mm were produced by adding these additive masterbatches with different concentrations to blown film processes.Shelf life analyses were performed in order to analyze the effect of composite packages on the products preserved inside them. In shelf life analyses, products like banana and strawberry were stored in the packages and gas changes in the environment and product properties were followed periodically. As a consequence of these analyses; it was determined that ethylene and carbondioxide gases in the environment were adsorbed by such a high level, 90% by adding modified natural zeolite minerals to package structure with 4%wt. Besides; gas permeability tests showed that oxygen and carbondioxide permeability values increased by up to 47% and 82% respectively. Moreover; superior anti-fogging properties and high antimicrobial effectiveness like 98.703% were obtained by surfactants based on Sorbitan Monolorat as 6%wt. and zeolite based silver ions as 1%wt. added to the structure respectively. It was determined that, shelf lives of the products stored inside the packages can be increased by different ratios between two to four times according to product types. Besides shelf life analyses, differential scanning calorimetry, thermo gravimetric analyses, scanning electron microscopy and mechanical analyses techniques were used in order to determine the physical and chemical properties of composite packages. In these analyses; it was determined that additives added to LDPE were dispersed homogenously, don?t change the mechanical properties such as tensile strength, don?t have a big effect on the crystallization and melting temperatures even if they increase the thermal degradation temperatures.