Phycocyanin Based Biodegradable pH-sensitive Smart Film for Food Packaging

Abstract

Freshness is crucial in consumer food purchases, emphasizing the need for effective quality monitoring in the food supply chain. This study developed a pH-sensitive film to monitor food freshness, using bacterial cellulose (BC) and phycocyanin, a pH-sensitive pigment with antioxidant and antimicrobial properties extracted from Spirulina sp. Colorimetric analysis showed a range of color variations from purple to greyish-red across pH ranging from 2 to 12. Incorporating phycocyanin at 1 mg/g did not result in significant color change, whereas higher concentrations of 2.5 mg/g and 5 mg/g enhanced the film's color. FTIR analysis revealed distinct phycocyanin peaks at 1649 cm⁻¹, 1522 cm⁻¹, 1390 cm⁻¹, and 1100 cm⁻¹ corresponding to C=O, -NH, C-H, and -OH bonds, respectively, in phycocyaninincorporated BC film, which were absent in pure BC film. XRD showed crystallinity at 66.48% for pure BC and 64.17% for the phycocyanin film, indicating a slight reduction in the crystalline nature of the BC. SEM results indicated phycocyanin binding to BC nanofibers, leading to a more homogeneous surface and enhanced nanofibril aggregation at higher concentrations. This film shows potential as a visual indicator for monitoring food freshness during storage