Stärkelse och hemicellulosa som barriärmaterial i livsmedelsförpackningar : En studie om materialens permeabilitet och struktur med polyvinyl alkohol som referens

To prevent permeation through food packages, the packaging are often combined with barrier coatings. Many of these coatings are petroleum based and wished to be replaced with renewable materials. The aim with this study was to produce laboratory barrier films of starch, hemicellulose and polyvinyl alcohol (PVA) and to examine the structures of these films and investigate how these barriers are affected by plasticizer additions. In this thesis PVA was mostly used as a reference material. In this way more knowledge can be obtained how the structures of the barrier affect the barrier performance. Different amounts of plasticizer, sorbitol, was added to the polymer solutions, different temperatures was used to dry the barriers and the barriers was coated with different thickness. The structure of the barrier was examined by several different analyses; oscillatory tests, scanning electron microscope (SEM), differential scanning calorimetry (DSC), permeability with oxygen transmission rate (OTR) and ambient oxygen transmission rate (AOIR). The results showed that sorbitol will be needed when making a barrier of starch and hemicellulose. This depends on the increasing entanglements in the polymers solutions when the sorbitol concentration is increasing; these entanglements decrease the glass transition temperature. Although, when the films are sticking together an increasing concentration of sorbitol seems to increase the permeability