Microencapsulation, Chemical Characterization, and Antimicrobial Activity of Mexican (Lippia graveolensH.B.K.) and European (Origanum vulgareL.) Oregano Essential Oils

Abstract

The effect of solvent polarity (methanol and pentane) on the chemical composition of hydrodistilled essential oils (EO's) of Lippia graveolens H.B.K. (MXO) and Origanum vulgare L. (EUO) was studied by GC-MS. Composition of modified starch microencapsulated EO's was conducted by headspace-solid-phase microextraction (HS-SPME). The antimicrobial activity of free and microencapsulated EO's was evaluated. They were tested against Salmonella sp., Brochothrix thermosphacta, Pseudomonas fragi, Lactobacillus plantarum, and Micrococcus luteus. Thymol and carvacrol were among the main components of EO's and their free and microencapsulated inhibitory activity was tested against M. luteus, showing an additive combined effect. Chemical composition of EO's varied according to the solvent used for GC analysis and to volatile fraction as evaluated by HS-SPME. Thymol (both solvents) was the main component in essential oil of MXO, while carvacrol was the main component of the volatile fraction. EUO showed α-pinene (methanol) and γ-terpinene (pentane) as major constituents, the latter being the main component of the volatile fraction. EO's showed good stability after 3 months storage at 4°C, where antimicrobial activity of microencapsulated EO's remained the same, while free EO's decreased 41% (MXO) and 67% (EUO) from initial activity. Microencapsulation retains most antimicrobial activity and improves stability of EO's from oregano.

Modified Starch-Chitosan Edible Films: Physicochemical and Mechanical Characterization

“…Antimicrobial activity was evaluated following the methodology of Hernández-Hernández [23]. Briefly, 10 mL of trypticase soy agar (0.8% w/v, Bioxon, Cuautitlan, México) was inoculated with 500 µL of L. innocua solution (10 7 CFU/mL), subsequently poured onto plates containing solidified agar (1.5% w/v).…”

How Soil-Applied Maltodextrin with Caraway (<i>Carum carvi</i> L.) Oil Affects Weed and Soil Microbiological Activity in Maize (<i>Zea mays</i> L.) Stands

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Production and characterisation of biodegradable PLA nanoparticles loaded with thymol to improve its antimicrobial effect

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