UV-resistant, antibacterial, antioxidant, and biodegradable alizarin/curcumin-based pH indicator film for monitoring shrimp freshness.

As quality of life improves, the demand for durable, eco-friendly active packaging materials has grown. This research utilized chitosan (CS) and transglutaminase (TG)-modified whey protein (WPI) as substrates. Loaded with alizarin and curcumin (AC) to prepare pH indicator films. SEM and FTIR confirmed uniform distribution of AC within the film matrix. When pitted against the TGWPI/CS film, the film containing 2 % AC boasted a tensile strength boost of 10.11 MPa, the elongation at break was increased by 15.17 %, an enhanced UV barrier by 16.99 %, and DPPH and ABTS reached 80.15 % and 66.69 %, respectively. The film's AC release rate was 68.23 %, primarily driven by Fickian diffusion. As the shrimp deteriorated, its color transitioned from yellow to a reddish-brown hue, allowing for accurate freshness evaluation without unpackaging. In summary, the results of the research showed that TGWPI/CS/AC film is expected to become a potential smart packaging material.