Investigation of the effect of adding propolis and turmeric extracts on the structural, functional, physical and thermal properties of films based on potato waste and Peruvian clay for potential food packaging applications

de Jara E.M.; Gutierrez-Oppe E.E.; Quequezana-Bedregal M.J.; de Alcântara Pessôa Filho P. · Brazilian Journal of Chemical Engineering (2026) · DOI: 10.1007/s43153-026-00701-4

Resumen

This study aimed to investigate the effect of adding propolis and turmeric extracts on the structural, functional, physical, and thermal properties of films based on potato waste (discarded potatoes and pulp) and Peruvian clay “chaco” for potential food packaging applications. The novelty of this work lies in the simultaneous use of turmeric extract (TE) and propolis extract (PE) as functional components. Turmeric was added at 1.7% w/w (0.05TE) and 2% w/w (0.06TE), and propolis was added at 3.3% w/w (0.10PE) and 5% w/w (0.15PE). The films were prepared via casting and characterized. SEM showed that the film 0.05TE-0.15PE exhibited the most homogeneous surface, consistent with FT-IR results, indicating strong molecular interactions among the components. This was associated with an improvement in the elongation at break (EB) to 31.8% compared to the control film (CF) at 25.6%. Similarly, the observed tensile strength (TS) showed a slight increase to 1.21 MPa compared to CF (1.13 MPa). The ΔE values ranged from 49.99 at pH 2 to 53.67 at pH 12, compared to the CF value of 12.09. The opacity increased to 6.14 mm⁻¹, compared to the CF value of 3.68 mm⁻¹. The contact angle increased to 60.7°, compared to the CF value of 49.6°, indicating increased hydrophobicity; the Tg decreased to 55 °C, compared to CF 85 °C. The WVP decreased to 8.25 × 10⁻¹⁰ g·m⁻¹·s⁻¹·Pa⁻¹, compared to CF 9.35 × 10⁻¹⁰ g·m⁻¹·s⁻¹·Pa⁻¹. The film also exhibited antimicrobial activity against S. aureus, with d = 9.67 mm. The films developed in this study are promising alternatives for food packaging applications. © The Author(s) under exclusive licence to Associação Brasileira de Engenharia Química 2026.

Instituciones: Universidad Nacional de San Agustín de Arequipa