Alkaline environment-dependent and moisture-activated catechu/guar gum coated oxygen scavenging labels for active food packaging

Abstract

In this study, an Acacia catechu (AC), sodium carbonate (NC), and guar gum (GG) based oxygen scavenging coated label with moisture activation was developed. The labels were prepared with different AC/NC ratios (1:1, 2:1, 3:1, 4:1, and 1:0, w/w) while maintaining a constant 1 % (w/v) concentration of guar gum across all samples and assessed for scavenging capabilities for 30 days at different temperatures (5℃, 25℃, and 40 ℃). Chemical changes during the scavenging reaction were observed through Fourier transform infrared spectroscopy. Additionally, rheological, morphological, and rub resistance properties were evaluated. The AC/NC-4:1 label demonstrated the highest oxygen scavenging capacity and rate of 3.12 ± 0.17 mL O₂/g and 0.1 mL O₂/(g day); 4.83 mL O₂/g and 0.13 mL O₂/(g day) at 25 ºC and 40 ºC respectively with no oxygen scavenging activity at 5 ºC. The AC/NC-4:1 formulation also yielded the highest catechin mass (5.906 mg gallic acid equivalent) via total phenolic content (TPC) analysis. In conclusion, the AC/NC-GG composition holds significant potential for developing oxygen-scavenging coated labels for active food packaging applications.