Pullulan/sodium alginate-based color-indicating film combined with Vaccinium vitis-idaea anthocyanins and ZnO nanoparticles for monitoring milk freshness

Area of Science:

• Food Science
• Materials Science
• Nanotechnology

Background:

• Smart and functional food packaging is crucial for extending shelf life and monitoring food quality.
• Developing active packaging with enhanced properties like UV-blocking, antioxidant, and antibacterial capabilities is an ongoing research area.
• Utilizing natural extracts and nanoparticles offers a sustainable approach to creating advanced food packaging materials.

Purpose of the Study:

• To develop pullulan/sodium alginate (Pul/SA)-based smart films incorporating Vaccinium vitis-idaea anthocyanins (ACNs) and zinc oxide nanoparticles (ZnO).
• To evaluate the impact of ACNs and ZnO on the film's UV-blocking, mechanical, antioxidant, and antibacterial properties.
• To assess the pH-responsive color-changing capabilities of the composite films for freshness indication in pasteurized milk.

Main Methods:

• Anthocyanin extraction from Vaccinium vitis-idaea and synthesis of zinc oxide nanoparticles (ZnO) via a hydrothermal method.
• Fabrication of Pul/SA composite films by dispersing ACNs and ZnO within the polymer matrix.
• Characterization of film properties including UV-blocking, mechanical strength, transparency, antioxidant activity, and antibacterial efficacy.
• Testing the pH-responsive color change of the films for monitoring pasteurized milk quality.

Main Results:

• The addition of ACNs and ZnO significantly improved UV-blocking and mechanical properties of Pul/SA films without compromising transparency.
• The composite films exhibited strong antioxidant activity (attributed to ACNs) and potent antibacterial properties (attributed to ZnO).
• The films demonstrated excellent pH-responsive color-change properties (dark brown to yellow), indicating freshness decline in pasteurized milk.

Conclusions:

• Pul/SA/ACNs/ZnO composite films are effective active and intelligent food packaging materials.
• The developed films offer enhanced functionality, including UV protection, antioxidant, and antibacterial properties.
• The pH-sensitive color change of the films provides a reliable visual indicator for monitoring food freshness, particularly in products like pasteurized milk.