Development of intelligent and active films based on potato waste, Peruvian clay, propolis and turmeric extracts as indicators of the durability and quality in foods

This study aimed to develop environmentally friendly films derived from natural waste, specifically post-harvest potato residues. The films incorporated turmeric extract (TE) as a pH-sensitive indicator and propolis extract (PE) as a natural antimicrobial agent, both intended to enhance food quality monitoring and shelf-life. Peruvian clay (“chaco”) was also employed as a reinforcing agent. TE was added at 0.05 g and 0.06 g per 3 g of starch, and PE was added at 0.1 g and 0.15 g per 3 g of starch. The films were prepared via casting and characterized using scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, water vapor permeability, contact angle measurements, opacity, and antimicrobial activity assays. Increasing the TE content reduced both elongation at break and water vapor permeability, whereas higher PE levels produced the opposite effect. Opacity increased with the addition of both extracts. Thermal stability improved with the lower concentration of PE and the higher concentration of TE. The incorporation of both extracts enhanced the contact angle and contributed to a more heterogeneous surface morphology. The highest concentration of PE exhibited the most effective antimicrobial activity against Staphylococcus aureus . The films developed in this study are promising alternatives for smart food packaging applications.