EFFECT OF ULTRASOUND ON MICROSTRUCTURAL AND PHYSICAL PROPERTIES OF EDIBLE FILMS DURING NANOEMULSIFICATION TREATMENTS

VASCO MF; GAMBOA SANTOS J.; CAMPAÑONE, L.A.

Congreso; 11th World Congress of Chemical Engineering; 2023

Nano-emulsification treatment could improve the stability of edible film used in packaging (EF) and coating (EC) applications [1]. The use of ultrasound (US), as a clean technology, is widely extended to obtain nano-emulsions with improved characteristics. However, due to the acoustic cavitation mechanism generated during US emulsification treatment, a series of reactions that change the physicochemical and microstructural properties of film-forming polymers could be generated. The objective of this work was to evaluate the impact of US assistance during nano-emulsification treatments on the properties of EF, considering three formulations of polysaccharides. Sodium carboxymethylcellulose (CMC), sodium-Ca+2 alginate (ALG) and cassava starch (CS) were used as base polymers. Sunflower oil was used as lipid phase and glycerol and tween 20 as plasticizing and emulsifying agents, respectively. The nano-emulsions were formulated through sonication treatment using an ultrasonic probe. The nano-emulsified edible film (ECMC, ECS and EALG) were obtained using the casting technique. They were characterized by studying their mechanical (parameters: tensile strain, TS, and elongation at break, E%), surface (contact angle, θ) and microstructural (SEM) properties. The results obtained were compared with the respective control (FC) without the addition of oil and US assistance (CMC, CS and ALG). The results indicated that the US assisted nano-emulsification treatment caused a decrease in TS along with an increase in E% for all the film evaluated. In turn, the contact angle values obtained for all the samples were related to hydrophilic surfaces. Despite this, the nano-emulsified samples were more hydrophilic than their respective controls. ECS showed the least hydrophilic behavior, which was related to the formed inclusion complexes of lipids and starch amylose. With respect to the EF microstructure analysis, ECMC and EALG showed a marked loss of uniformity with respect to their controls, showing coalescence and cracks in the EF structure. However, ECS showed a uniform surface, with droplets perfectly embedded in the matrix, as a result of the aforementioned inclusion complexes. The US treatment as a nano-emulsifying technology significantly influenced the polymer dispersions and the properties of the resulting film. In accordance with the uniformity and retention of lipids, it was considered that ECS could be a promising alternative to be used as EF or EC for food preservation purposes.