Composite films based on pumpkin oil cake obtained by different filtration process

Packaging is inseparable retainer of almost all food products. However, most of produced packaging ends as packaging waste after consumption of the product. Increasing amounts of packaging waste that should be managed represents serious challenge of every modern society. There are many different approaches to address this subject, amongst which biodegradable, natural biopolymer-based or even edible packaging holds considerable potential. In this paper, a by-product of edible oil industry, left after completed extraction by cold pressing of oil from hulls of pumpkin seeds, was used to produce biopolymer packaging films. Pumpkin oil cake was used to produce composite bio-based films. Different filtration of film forming suspension was applied in order to test composite film production using different filtration fractions, leading to higher process yield and minimizing waste. In addition, films were casted on surface, about ten times larger comparing to the cast surface typically reported for these types of films in the literature, in order to test the possibility for commercial production and scale up process. Also, casted mass of film forming suspension was varied in order to define minimal casting mass per unit area. Presented results showed that biopolymer films based on the pumpkin oil cake can be successfully produced in sheets (50x35 cm), compared to films earlier produced in the form of discs with diameter 12 cm. Different filtration fractions from initial film forming suspension can be used for film formation, leading to increased production yield. Different filtration fractions lead to different film properties that should be adjusted according to selected application. Casted mass of film forming suspension was successfully decreased (comparing to earlier literature data) without compromising film functional properties and minimal casting mass was defined as 26 g/m2.