Carvone

D-Limonene, gelatin (type A with an isoelectric point of 7), n-hexane, pepsin, pancreatin 8XUSP were purchased from Sigma Aldrich (St. Louis, MO, United States). High viscosity sodium alginate (GRINDSTED Alginate FD 155) with pKa of 3.5 (Dupont Nutrition and Health, New Century, KS, United States) was selected for maximizing the extent of complex coacervation (16 , 24 (link)). Succinic acid, ammonium hydroxide, sodium hydroxide, sodium chloride and isopropanol were purchased from Fisher Scientific (Fair Lawn, NJ, United States). Anti-foam reagent was purchased from Spectrum Chemicals Mfg Corp (New Brunswick, NJ, United States). Aquacoat^® ECD 30 (aqueous colloidal dispersion of ethylcellulose polymer-30% ethylcellulose stabilized by sodium lauryl sulfate (SLS) and cetyl alcohol) was provided by Colorcon (Harleysville, PA, United States) and tributyl citrate was purchased from TCI America (Portland, OR, United States). Limonene, carvone and Limonene oxide standards were purchased from Sigma Aldrich (St. Louis, MO, United States).

2-Butanone (≥99%), 2-furaldehyde (≥99%), 2-methylbutanal (90%), 4-heptanone (97%), carvone (≥98.5%), decanal (95%), decane (≥99%), formaldehyde (37% aqueous solution), hexanal (97%), methylglyoxal (40% aqueous solution), O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine hydrochloride (PFBHA) (≥ 99%), octanal (≥99%) and p-cresol (4-methylphenol) (≥98%) were purchased from Sigma-Aldrich (Madrid, Spain). Sodium chloride was supplied by VWR (Leuven, Belgium).

Bornyl acetate (99%), camphene (95%), camphor (96%), carvarol (98%), (−)-carveol (95%), (+)-carvone (96%), β-caryophyllene (98.5%), caryophyllene oxide (95%), β-citronellal (95%), citral (95%), 1,8-cineole (99%), p-cymene (99%), decyl chloroformate (97%), dodecanoic acid (98%), β-farnesene (90%), geranyl acetate (97%), geraniol (98%), isopulegol (98%), linalool (97%), limonene (97%), limonene oxide (97%), methyl linolenate (99%), myrcene (90%), myristic acid (99%), palmitic acid (99%), α-phellandrene (85%), α-pinene (98%), pivalic acid (99%), sabinene (75%), α-terpineol (90%), γ-terpinene (97%), 4-terpineol (95%), terpinolene (90%), and tymol (99%) were obtained from Sigma-Aldrich (St. Louis, MO, USA). Achillea millefolium L. flowers, Citrus aurantium L. fruits, Leptospermum petersonii F. M. Bailey leaves, Ruta graveolens L. leaves, and Thymus vulgaris L. leaves were collected from a local store in Chonju, Korea. Sample specimens were authenticated by Jeongmoon Kim at Chonbuk National University, Korea. Essential oils of the five plants were obtained by steam distillation extraction, and finally dried over Na₂SO₄ to extract the pure essential oils (Table 1).

Citral and carvone (Sigma-Aldrich, USA) were used to perform the microbiological tests.

For identification of volatiles the following analytical standards were purchased from Sigma-Aldrich (Milan, Italy): α-pinene, β-pinene, p-cymene, limonene, γ-terpinene, linalool, trans-pinocarveol, terpinen-4-ol, α-terpineol, myrtenol, nerol, carvone, geraniol, geranial, eugenol, (E)-caryophyllene, α-humulene, (E)-β-farnesene, (E)-β-ionone, (E)-nerolidol, caryophyllene oxide, n-pentacosane, n-heptacosane; (E)-Phytol was previously isolated from Onosma echioides [43 (link)]. For retention-index (RI) determination, a mixture of hydrocarbons, ranging from octane (C₈) to triacontane (C₃₀) (Supelco, Bellefonte, PA, USA) was used and run under the experimental conditions reported below. All compounds were of analytical standard grade. Analytical-grade hexane solvent was purchased from Carlo Erba (Milan, Italy); it was successively distilled through a Vigreux column before use.