Impacts of Sample Preparation Methods on Solubility and Antilisterial Characteristics of Essential Oil Components in Milk

Abstract

Essential oil components (EOCs) have limited water solubility and are used at much higher concentrations in complex food matrices than in growth media to inhibit pathogens. However, the correlation between solubility and activity has not been studied. The objective of this work was to characterize the solubility of EOCs in solvents and milk and correlate solubility with antilisterial activity. The solubilities of four EOCs, thymol, carvacrol, eugenol, and trans-cinnamaldehyde, in water was significantly increased in the presence of 5% (vol/vol) ethanol. In milk, the solubility of EOCs was lower than in water, with lower solubility in higher-fat milk. EOCs applied to milk as stock solutions (in 95% aqueous ethanol) enabled quicker dissolution and higher solubility in milk serum than other methods of mixing, such as end to end, and greater reductions of Listeria monocytogenes Scott A after 0 and 24 h. When the EOC concentration detected in milk serum was above the minimum bactericidal concentration, complete inhibition of L. monocytogenes in tryptic soy broth resulted. Therefore, the antilisterial properties in milk could be correlated with the solubility by comparison to the minimum inhibitory or bactericidal concentrations of EOCs. While the EOCs applied using ethanol generally had solubility and activity characteristics superior to those of other mixing methods, ethanol is not used to a great extent in nonfermented foods. Therefore, mixing methods without an organic solvent may be more readily adaptable to enhancing the distribution of EOCs in complex food systems.

Development of gold nanoparticles coated with silica containing the antibiofilm drug cinnamaldehyde and their effects on pathogenic bacteria

“…23 However, the clinical use of CNMA is made difficult due to its instability, poor aqueous solubility, poor dispersability, toxicity, and because it is difficult to deliver it to target sites at required concentrations. [24][25][26] The delivery of CNMA encapsulated in nanocarriers could overcome these problems, but the antibiofilm activity of CNMA conjugated on GNPs has not been previously explored.…”

Enhanced resistance against Vibrio harveyi infection by carvacrol and its association with the induction of heat shock protein 72 in gnotobiotic Artemia franciscana

“…It is important to mention that carvacrol is lipophilic and is sparingly soluble (forms small globules) in water (Chen et al 2014). In this study, stock solution of carvacrol was prepared by dissolving the compound in water rather than in organic solvents (such as ethanol).…”

Eugenol Nanoencapsulated by Sodium Caseinate: Physical, Antimicrobial, and Biophysical Properties

“…The sample injection volume was 10 μL, and the detector wavelength was 274 nm. A binary solvent mixture of water and methanol was used at a linear gradient from 20% to 80% methanol within 20 min for elution [16]. The flow rate was 0.5 mL/min, and the column chamber was controlled at 25 °C.…”

“…1.35 mg/mL at 21 °C [16], the amount of eugenol dissolved in water was quantified. Excessive eugenol (10.0 mg/mL) was added into water and stirred using a stir plate at RT for at least 24 h, and then the oil content in the water phase was measured using HPLC after dilution and filtration as described above.…”

“…NaCas consists of mixtures of α s1 -, α s2 -, β-, and κ-caseins at proportions of approximately 4:1:4:1 that are all known to be surface active, with β-casein being recognized for the greatest contributor of emulsifying properties [18]. Thymol has a melting point of about 50 °C [19] and a water solubility of 0.48 mg/mL at 21 °C [16], whereas eugenol is a liquid and has a water-solubility of 1.50 mg/mL at 21 °C measured in the present study, with the latter agreeing with the previously reported solubility of 1.35 mg/mL [16]. The higher hydrophilicity of eugenol than thymol results in a lower oil/water interfacial tension and the higher fluidity (liquid vs. solid) lowers the viscosity of the dispersed phase during emulsification, which favor emulsion formation during shear homogenization.…”