Dados do Trabalho

Título

Development and characterization of sustainable antimicrobial films based on babassu mesocarp starch: the role of natural deep eutectic solvent (NADES) as plasticizer.

Introdução

The babassu oil extraction results in the production of by-products as mesocarp and almond cake (BC). This study aimed to evaluate BC extracts using different NADES as antimicrobial additives and plasticizers in babassu mesocarp (BMS) films.

Material e Métodos

The NADES formulations contained choline chloride in combination with citric acid or urea with 30% or 40% water were prepared by heating (60°C) and stirring (2h). For extraction, 1 g of BC was dispersed in 19 g of different NADES, kept in an ultrasonic bath (2h) and filtered to obtain the supernatant. Film-forming films were developed: (1) a control film (MB) containing 4 g of BMS, 96 g of distilled water and 30 g of glycerol per 100 g of BMS; and (2) experimental formulations containing 100 g of each BC-NADES extract per 100 g of BMS (citric acid - CA30 and 40%; urea - U30 and 40%). The solutions were homogenized (30 min) and heated (90°C/15 min). The plasticizer (glycerol or BC-NADES extract) was added, heated for 15 min and poured onto acrylic plates (0.30 g/m2) and oven-dried at 35°C (casting method).

Resultados e Discussão

MB showed a tensile strength (TS) of 10.55±2.84 MPa, an elongation at break (EB) of 8.17±1.6%, Young's modulus (YM) of 1.31±0.48 MPa, a moisture content (MC) of 15.24±2.15%, a water solubility (WS) of 20.69±0.5% and an opacity of 5.30±0.08 mm-¹. CA30/40 and U30/40 films, on average, showed respectively TS: 4.26±0.52 and 2.54±0.54 MPa; EB: 38.69±9.96 and 38.03±12.1%; YM of 1.59±0.36 and 0.3±0.08 MPa, MC of 12.72±3.3, and 18.26±1.41%, WS of 35.68±3.3 and 31.88±5.91 % and opacity of 4.56±0.16 and 5.3±0.35 mm-¹. CA films demonstrated susceptibility to bacteria using the agar diffusion method for Staphylococcus aureus, Escherichia coli, and Listeria monocytogenes, with mean diameters of 8.5 ± 1.8 mm, 10.5 ± 1.2 mm, and 19.25 mm, respectively.

Conclusão

The addition of both NADES produced films with lower TS but higher elongation capacity, greater water solubility, and less opacity. Films with these characteristics are suggested for use as substitutes for PVC plastics in covering vegetables. The BC extracts, employing different NADES, functioned as plasticizers, and CA films also exhibited antimicrobial potential.