Active Polysaccharide Films Incorporating Cannabis sativa Flower Extract for Extending the Shelf Life of Freeze-Dried Berries

In this study, films based on polysaccharides with C. sativa flower extract were prepared for selected freeze-dried fruits: raspberry (Rubus idaeus L.) and blueberry (Vaccinium corymbosum L.). The extract used affected the barrier and mechanical properties of the film. The elongation values of the film ranged from 32.5 ± 8.6 [%] (for sample 0) to 44.8 ± 8.2 [%] (for sample 4.0 F). The addition of the extract resulted in an increase in polyphenol content, proportional to the quantity of extract used. Spearman's rank correlation analysis showed particularly strong correlations between colour indices (L*, a*, b*) and parameters describing antioxidant activity. The use of C. sativa flower extract in the polysaccharide matrix reduced the degradation of bioactive compounds during the storage of packaged fruit. In all cases of stored raspberries, a decrease in the number of moulds and yeasts was observed after 2 and 8 weeks. The greatest reduction in moulds and yeasts was recorded for the 4.0 F film (from 0.86 to 0.64 log cfu/g). In the case of blueberries, the total number of bacteria before storage was 2.52 log cfu/g, while after 8 weeks of storage in 4.0 F, this number significantly decreased to 2.28 log cfu/g. As in the case of raspberries, a reduction in mould and yeast was observed, with concentrations falling from an initial value of 0.89 to 0.67 log cfu/g after 8 weeks of storage at 4.0 F.