Arum Widyastuti Perdani, Arima Diah Setiowati, Bambang Purwono, Supriyadi Supriyadi
This study investigated co-pigmentation with gallic acid on the stability and functional performance of rambutan peel anthocyanins extract (RPAE) incorporated into gelatin-chitosan films for active and colorimetric intelligent food packaging. Films were prepared by the casting method using gelatin-chitosan matrices containing 0.5%, 1.0%, and 1.5% native or co-pigmented RPAE. Co-pigmented RPAE films showed increased tensile strength to 8.73 ± 0.67 MPa and decreased elongation at break to 93.02 ± 8.59% due to the hydrogen bonding and π-π stacking cross linking effect. Co-pigmented RPAE films reduced water vapor permeability to 2.109 × 10− 7 ± 9.051 × 10− 9 gH₂O·m/m²·h·Pa and lowered the water contact angle to 47.49°, indicating a denser yet more hydrophilic film surface. It improved film responsiveness, as evidenced by color transitions from red to yellow across pH 1–14 and from pale to dark yellow upon exposure to ammonia, trimethylamine, and dimethylamine, which are the major volatile compounds during food spoilage. UV-blocking efficiency increased in films containing co-pigmented RPAE, likely due to enhanced molecular interactions between anthocyanins and gallic acid during co-pigmentation, as verified by Fourier transform infrared spectroscopy. Co-pigmentation also retained anthocyanins and phenolics after drying, yielding 0.115 ± 0.008 mg C3G /g and 560.57 ± 9.11 mg GAE /g. Consequently, the films demonstrated strong antioxidant activity and more effective inhibition of Staphylococcus aureus than Escherichia coli. Scanning electron microscopy further revealed greater surface roughness and reduced cracking in co-pigmented films. Overall, gelatin-chitosan films containing co-pigmented RPAE show strong potential as sustainable active and intelligent food packaging materials. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2026.
Department of Food and Agricultural Product Technology, Faculty of Agricultural Technology, Universitas Gadjah Mada, Special Region of Yogyakarta, 55281, Indonesia; Applied Culinary Arts Study Program, Faculty of Vocational Studies, Universitas Negeri Yogyakarta, Gunungkidul Campus, Special Region of Yogyakarta, 55893, Indonesia; Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Gadjah Mada, Yogyakarta, 55281, Indonesia; Center of Excellence for Indonesian Gastronomy, Universitas Gadjah Mada, Yogyakarta, 55281, Indonesia
