Development of a blue innovative antioxidant, biodegradable packaging material with Clitoria ternatea L. flos

Today, the packaging industry, and in particular the plastic packaging industry, are going to experience a number of challenges as a result of the provisions included in the directive on reducing the environmental impact of plastic packaging materials. Therefore, much attention is being paid to bio-based packaging based on natural and biodegradable polymers. Focus is being placed on natural additives with antioxidant properties to materials, eliminating the risks associated with the migration of chemical, often harmful substances into food. Therefore, in the present study, we obtained a blue antioxidant and biodegradable packaging material with flowers of Clitoria ternatea L., which is additionally safe against selected plants and invertebrates. Furthermore, we observed that the addition of blue matcha improved the barrier properties of the tested films. Samples with matcha CM (cellulose/matcha) and CZM (cellulose/gelatin/matcha) showed WVTR values of 14.44 [g/m2ˑd] and 9.34 [g/m2ˑd], respectively. Antioxidant activity testing by both the DPPH radical and FRAP methods showed the activity of the film containing the matcha extract. The extract alone had the highest activity (DPPH IC50 = 1.44 mg/ml; FRAP IT0.5 = 0.64 mg/ml). CM film had stronger antioxidant activity than CZM film. The film samples without matcha were characterised by TS values of 13.54 [MPa] and 22.24 [MPa], respectively. In contrast, their elongation at break was 74.87 [%] and 41.04 [%]. The samples containing matcha additives showed the weakest mechanical properties: CM and CZM. The cellulose/matcha film (CM) had TS and EAB values of 5.11 [MPa] and 5.05 [%], respectively. Whereas the cellulose/gelatin/matcha film (CZM) had TS and EAB values of 6.45 [MPa] and 1.54 [%], respectively. Application of a high concentration of matcha resulted in a separation of the phase leading to a weakening of the mechanical properties of the films. The observed change in the optical performance of matcha-containing films in this study was due to the blue colour of matcha, which is an effect of the presence of dried flowers. Furthermore, the blue colour of the packaging material has a marketing role as it can make the packaging product ‘stand out’ on the shop shelf.