Influence of guar-xanthan addition on mechanical properties of pumpkin oil cake biopolymer films

The application of biopolymer films and coating to food products represents a new approach to reduce r migration of moisture, oxygen, carbon dioxide, aromas, and oil in or out of food. Also, biopolymer films, as packaging materials, need to enhance appearance of food and to improve mechanical integrity. In order to facilitate handling and application films must be strong, but flexible enough. Addition of plasticizer could modify the flexibility of biopolymer films. It is known that guar-xanthan can improve the flexibility of polysaccharides films. Therefore, the objective of this study was to examine the influence of guar-xanthan on characteristics of pumpkin oil cake (PuOC) films, with emphasis on the flexibility of the film. Two approaches of guar-xanthan addition in the pumpkin oil cake were applied - stirring with laboratory stirrer and using of ultra turrax homogenizer. The results showed that guar-xanthan improved physical and mechanical properties of PuOC films, but only if film-forming solution was homogenized by ultra turrax. The films with guar-xanthan slightly improved mechanical properties - tensile strength and elongation at break, water content, solubility and swelling properties, but were much easier for handling.