Avaliação da atividade antimicrobiana de nanopartículas de curcumina e aplicação de microcristais de curcumina em cenoura minimamente processada

Abstract

Curcumin is a phenolic, natural compound isolated from Curcuma longa which presentsmany biological properties including antimicrobial activity. Its low water affinity can beimproved by increasing total surface area by either encapsulation or micronization. Theobjective of this work was to evaluate the antimicrobial activity of curcumin-polyvinylpyrrolidone nanoparticles and curcumin microcrystals. In the case of in naturacurcumin and curcumin nanoparticles, the agar dilution technique was used against Gram-negative (Escherichia coli and Pseudomonas aeruginosa) and Gram-positive (Bacilluscereus and Staphylococcus aureus) bacteria. Curcumin microcrystals were used as a preserving agent in the production of minimally processed carrots and the evaluated parameters were mesophilic and psychrotrophic bacteria and total coliforms. Nanoparticles were characterized for sizes distribution, encapsulation efficiency, thermalproperties and chemical interactions between curcumin and polyvinylpyrrolidone by infrared spectroscopy. High encapsulation efficiency was found in accordance with thedisappearance of the fusion peak of curcumin and the infrared absorption band at 3508 cm-1 related to the phenolic group. In natura curcumin presented antimicrobial activity in concentrations from 250 to 500 µg.mL-1 depending on the microorganism. Curcumin nanoparticles did not present activity in the evaluated concentration range, possibly due to the hydrogen bonds formed between curcumin and polyvinylpyrrolidone.Curcumin microcrystals were able to significantly inhibit mesophilic and psychrotrophicbacteria and total coliforms in the minimally processed carrots.