Dados do Trabalho

Título

Mechanical and biological properties of sodium alginate and carboxymethylcellulose-based films incorporated with nanoemulsified cinnamon essential oil

Introdução

The physical properties of polymer films are closely linked to their microstructure. Studies have shown that the addition of essential oils to polymeric solutions can improve characteristics such as tensile strength, hydrophobicity and flexibility. In this study, the objective was to evaluate the physical and biological properties of films based on sodium alginate, with (SA+) and without (SA-) crosslinking by calcium chloride, carboxymethylcellulose (CMC) and nanoemulsified cinnamon essential oil (NeCEO).

Material e Métodos

NeCEO was prepared by mixing water, polysorbate 80 and cinnamon essential oil, followed by ultrasound (150W/3 min). Films were then prepared by homogenizing NeCEO with SA, CMC and glycerol, followed by casting and drying. The average droplet size, Zeta potential and polydispersity index of NeCEO were evaluated. The films were tested for tensile strength, puncture resistance and contact antifungal activity against Colletotrichum spp. Films without NeCEO were used as controls.

Resultados e Discussão

All treatments resulted in flexible films. The average droplet size, Zeta potential and polydispersity index of NeCEO were 60.59 ± 0.2 nm, -31.7 ± 1 mV and 0.2 ± 0.00, respectively. Young's modulus, elongation (AR) and stress at break (TS) values varied between 2.34 ± 0.25 and 3.21 ± 0.44 MPa, 4.67 ± 0.52 and 6.28 ± 0.49, and 20.33 ± 1.86% and 42.02 ± 4.06 MPa, respectively.

Conclusão

It was observed that the cross-linked films were significantly more resistant than the non-cross-linked films (p <0.05), evidenced by the higher stress values at break. This suggests that cross-linking increased the mechanical strength of the films, making them more robust and requiring more force to break them. On the other hand, a significant reduction in TS was observed with the addition of essential oil. The incorporation of extrapolymeric components generally reduces TS, due to the heterogeneous formation of film structure, presenting discontinuities, which reduces the mechanical resistance of the films. In the antifungal analysis, the region in which the films incorporated with NeCEO were placed did not show growth, demonstrating the antifungal potential by contact. These data reveal the potential of SA and CMC-based films incorporated with NeCEO to reduce anthracnose symptoms and can be applied to different foods.