Visual quality control of perishable foods is essential for food safety, driving the need for sustainable materials that change color with pH variations. This study developed chitosan (2%), alginate (2%), and chitosan/alginate (3:1, 2%) films incorporating açaí anthocyanins as natural pH indicators. Solutions of chitosan and alginate were prepared at room temperature with 0.5% glycerol, soybean oil, Tween 80, and lyophilized clarified açaí (2.7 ± 0.091 g/100 g anthocyanins), then homogenized. Each formulation (30 mL) was spread on 12 cm Petri dishes and dried at 35 °C over 48 hours. Film samples (9 cm²) were immersed in pH 4 and pH 1 buffers, with anthocyanin quantification at 5 min, 24 h, and 72 h. Alginate films dissolved quickly, precluding anthocyanin quantification, while chitosan films released 7.83 ± 0.60% of anthocyanins at 5 min, 46.47 ± 0.36% at 24 h, and 54.44 ± 0.70% at 72 h. Chitosan/alginate films showed slower release, with 6.64 ± 0.79% at 5 min, 18.40 ± 0.21% at 24 h, and 22.06 ± 0.55% at 72 h. The prolonged retention of anthocyanins in chitosan/alginate films (p < 0.001) is attributed to the enhanced ionic interactions between the chitosan and alginate polymers, forming a cross-linked structure that restricts anthocyanin diffusion. These findings suggest that films with 75% chitosan and 25% alginate are promising for visual food quality indicators. Further research should focus on optimizing the chitosan-alginate ratios and incorporating cross-linking agents to enhance stability and effectiveness. This formulation, leveraging natural Amazonian resources, contributes to sustainability and the bioeconomy.