Betanin and Nano-Calcium Carbonate Incorporated Polyvinyl alcohol/Starch Films for Active and Intelligent Packaging Applications

Bio-based and biodegradable packaging are ideal for sustainable polymer packaging. In this study, cassava starch and polyvinyl alcohol (PVA) were used as the film-forming matrix, betanin (E-162) and nano-calcium carbonate (CaCO3) as the pH sensitive pigment and nanofiller, respectively. Solvent casting technique was used to develop ecofriendly composite films. For the first time, the color, mechanical, thermal, structural, ammonia sensitivity, and bioactivity properties of films containing different amounts of natural additives were compared. The changes determined in the Fourier transform infrared (FT-IR) spectrum were evidence of the interaction of additives with polymer matrix. The developed films showed similar thermal stability according to thermal degradation behaviors with three distinct weight losses. The temperatures of 10% residual weight were determined to be slightly higher (500.4-603.8 °C) in additive incorporated films when compared to pure PVA/starch film (478.3 °C). The mechanical properties of composite films varied due to composition. The tensile strength of pure PVA/starch films were reduced significantly from 27.74 to 16.56 MPa with betanin addition. The together addition of betanin (E-162) and nano-CaCO3 also reduced the tensile strength (14.77 MPa). The elongation at break values of betanin incorporated films (% 184.06-205.09) were reduced as compared with pure PVA/starch films (% 258.10). The additives caused a decrease in L* values (lightness reduction). The addition of betanin to PVA/starch film notably improved the antioxidant properties. The results demonstrate the convenience of the composite films for active and intelligent packaging applications.