Polymer nanocomposites as active food packaging materials to improve the shelf life of fruits and vegetables

Official URL: https://risc01.sabanciuniv.edu/record=b3150836_(Table of contents)

In this thesis, important solutions to the concept of food safety and preservation of food quality, which has become increasingly important recently, has been offered with the development of multifunctional hybrid nanocomposite materials containing natural and environmentally-friendly components. Specifically, the studies have focused on the prevention of food spoilage and waste during post-harvest stages and two different hybrid nanocomposite materials that can protect and prolong the shelf-life of fresh produce during storage and transportation was designed. The first design included active food packaging films that can slowly release a natural active agent, which can slow down the ripening of fruits. Halloysite clay nanoparticles were impregnated with cinnamaldehyde essential oil and the obtained sustained release system was incorporated into polypropylene matrix, resulting in nanocomposite food packaging films that can release cinnamaldehyde to inhibit the production of fruit-ripening ethylene gas. The ripening of bananas packaged with these nanocomposite films was demonstrated to be delayed and bananas were shown to be stored fresh for a longer period of time than unpackaged bananas. In the second design, viii natural clay nanoparticles were integrated into foamed waterborne polyurethane matrix to produce novel, flexible, fresh-keeping and atmosphere regulating nanocomposite foams, which can be used as packaging inserts that can increase the shelf life of fruits. The nanocomposite foam was demonstrated to absorb both the fruit-ripening ethylene gas produced by the fruits and the excess moisture, thus delay the post-harvest ripening and spoilage in different fruits tested. The ethylene production inhibiting food packaging films and the ethylene and moisture absorbing foams presented in this thesis have a strong potential as food packaging materials that improve the shelf life of fresh produce and contribute to the prevention of food spoilage and waste.