Antimicrobial and antioxidant activities of carvacrol microencapsulated in hydroxypropyl-beta-cyclodextrin

Abstract

Carvacrol is a hydrophobic compound that exhibits high antimicrobial and antioxidant activities. Cyclodextrins are used to increase solubility and dissolution through water-insoluble compounds inclusion into their hydrophobic cavities. Hence, this study aimed to characterize carvacrol inclusion complexes with hydroxypropyl-beta-cyclodextrin (HPBCD) by establishing the physico-chemical properties and evaluate their antimicrobial and antioxidant properties. Inclusion complexes were prepared by kneading (KN) and freeze-drying (FD) methods. Entrapment efficiency was 78.09 ± 1.24% for KN, and 83.74 ± 1.15% for FD. Polydispersity index was greater than 0.2 for both methods. Particle size for KN and FD were 0.360 ± 0.003 and 0.377 ± 0.007 μm, respectively. Carvacrol–HPBCD antimicrobial activity was higher (P < 0.05) than for free carvacrol for both bacteria, Escherichia coli K12 and Salmonella enterica serovar Typhimurium LT2, indicating that HPBCD increased water solubility and consequently increased contact between carvacrol and bacteria in medium. Antioxidant activity was lower (P < 0.05) for inclusion complexes indicating HPBCD makes carvacrol less available to react with free radical. The stability study indicated that light did not affect (P > 0.05) degradation, indicating that the microparticles were stable throughout storage. Therefore, carvacrol–HPBCD complexes may have important applications in the food industry as stable antimicrobial systems.