Development of biodegradable smart packaging from chitosan, polyvinyl alcohol (PVA) and butterfly pea flower’s (Clitoria ternatea L.) anthocyanin extract

Active compounds from natural sources such as butterfly pea flowers (Clitoria ternatea L.) such as anthocyanin was found able to be integrated with chitosan and Polyvinyl Alcohol (PVA) polymers in their application as smart packaging. Smart packaging that contains anthocyanin shows a colour response to changes in pH due to food spoilage. This study was aimed to evaluate the effects of chitosan (CH) and PVA proportion on the quality of biodegradable film incorporating butterfly pea flower’s anthocyanin (BPFA) extract included film thickness, tensile strength (TS), elongation (E%), total anthocyanin content and the film colour response at different pH range were characterized. Concentrated anthocyanin extract was obtained from butterfly pea flower petals in ultrasonic-assisted leaching using ethanol as a solvent and followed by rotary vacuum evaporation. The film-forming solution was prepared from a binary mixture of CH:PVA in the ratio of 20:80, 40:60, 60:40, and 80:20. The results showed that films obtained from all combinations could exhibit different colour responses in various pH ranges, indicating the successful incorporation of anthocyanin. The film with CH:PVA ratio of 40:60 showed a more pronounced colour change, among other treatments. It was also characterized by a thickness of 0.15 mm, TS of 11.02 MPa, E% of 48.00%, and total anthocyanin of 25.08 mg/g. The film showed high potential to be used as biodegradable smart packaging for the food system which produces pH change upon deterioration.