Odors geranium

In 1961, chemists (19) isolated a minor component of geranium oil, characterized it as rose oxide (1), and reported that this compound contributed to the characteristic geranium odor. Rose oxide (1) is manufactured by the photooxidation of citroneUol (8). 

Palmarosa Oil occurs as a light yellow to yellow oil that is often hazy and brown with a rosy, floral, geranium odor. It is the volatile oil obtained by steam distillation from the partially dried grass Cymbopogon martini Stapf. var. motia (Fam. Gramineae). It is soluble in most fixed oils and in propylene glycol. It is soluble, usually with opalescence or turbidity, in mineral oil. It is practically insoluble in glycerin. 

Properties Oily liquid having a geranium odor. Sp. gr. 1,88. B. P. 190°. A persistent, violent vesicant, highly toxic (arsenical poison). Can be used in liquid or vapor form, in other words, in shells, bombs, or as a spray. Decomposed by hydrolysis. Alcoholic sodium hydroxide spray used as means of destroying the product in the field, after first washing down with water. 

Edinger, W.D. and Splittstoesser, D.F. (1986). Production by lactic acid bacteria of sorbic alcohol, the precursor of the geranium odor compound, Am. J. Enol. Vitic., 37,34-38. 

Monocline prisms geranium odor, d 1.235 mp 70 bp 314. Insoluble in water freely sol in hot alcohol slightly sol in cold alcohol or ether. 

Physical Description Colorless to straw-colored liquid with a mild, geranium odor. I ... 

Lewisite (L) Colorless to amber or brown oily liquid with geranium odor 0.39 mm Hg 4,480 mg/m Volatile Days LC501200 mg-min/m LD50 40-50 mg/kg Immediate pain, tissue damage in seconds to minutes fluid-filled blisters... 

Properties Colorless cryst. geranium odor sol. in ethanol, benzene, diethyl ether, glac. acetic acid misc. with oxygenated soivs. insol. in water m.w. 170.21 dens. 1.073 vapor pressure 0.0213 mm Hg m.p. 26-30 C b.p. 259 C flash pt. 96 C autoignition temp. 618 C ref. index 1.5790 surf, tens. 38.82 dynes/cm... 

Properties Colorless to pale yel. oily liq., pleasant geranium odor sol. in fixed oils, propylene glycol ... 

Properties Rose-geranium odor m.w. 252.40 dens. 0.890 (15.5 C) b.p. 240 C ref. index 1.4500 Toxicology Skin irritant TSCA listed Hazardous Decomp. Prods. Heated to decomp., emits acrid smoke and irritating fumes Uses Synthetic flavoring agent in foods and pharmaceuticals cosmetics ingred. 

Bacteria are not affected by sorbic acid, and, in fact, several species can metabolize the acid to eventually yield 2-ethoxyhexa-3,5-diene, a compound that imparts a distinctive geranium odor/tone to wines (Section 11.3.5). Other odor/flavor-active compounds detected in spoiled wines treated with sorbic acid include l-ethoxyhexa-2,4-diene and ethyl sorbate (Chisholm and Samuels, 1992), the latter of which has been associated with off-flavors in sparkling wines (De Rosa et al., 1983). Whereas Chisholm and Samuels (1992) described ethyl sorbate as possessing a honey or apple aroma, De Rosa et al. (1983) thought the compound imparted a very unpleasant pineapple-celery odor upon short-term (6 month) storage. Based on this observation, De Rosa et al. (1983) recommended that sorbates should not be used in sparkling wine production. 

Figure 11.5. Microbiological formation of geranium odor or tone.

It is almost impossible to remove the geranium odor from a wine. Since it is still perceptible after significant dilution, blending is not recommended. The most drastic deodorizing treatments fail (fixation on active charcoal, extraction by oil, etc.). The odor passes during distillation and is concentrated in spirits—only a severe oxidation with potassium permanganate eliminates it. Fortunately, the necessary conditions to avoid this serious spoilage (the rational use of SO2) are now well known and this problem has practically disappeared. 

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