Bitter Almond Oil

#### Almond Oil, bitter. An essential oil which is commercially known as **Bitter**** ****Almond**** ****Oil**** **can be distilled from one of the following materials: - The partially de-oleated press-cake of **Bitter**** ****Almond**** **kernels from the tree **Prunus**** ****Amygdalus**, var. amara., or - The partially-de-oleated press-cakes from the kernels of: Apricots (from **Prunus Armeniaca**, the peach tree), Cherries (from **Cerasus**** **species, various cherry trees), Plums (from **Prunus**** ****Domestica**, tree of blue preserve-plums), Peach (**Amygdalus Persica**, the peach tree), the latter being of little importance in respect to production of **Bitter**** ****Almond**** ****Oil.** The **Bitter Almond Tree **is cultivated particularly in the U.S.A., Israel, Syria, Turkey Morocco, Spain and France. Apricot kernels are plentiful in California, U.S.A. and in Israel. Distillation of essential oil from one or more of the above raw materials is carried out in the U. S. A., France, Israel, England, Holland, etc. Prior to distillation, the press-cake is macerated in luke-warm water for 12 to 24 hours. This allows the formation of the essential oil which is not present as such either in the kernels or in the dry, partially deoleated press-cake. The above botanical materials contain a glycoside, **Amygdalin**, in the kernels. Enzymatic processes initiate the decomposition of this glycoside, whereby **Benzaldehyde **and **Hydrocyanic Acid **are formed. The crude essential oil thus contains ‘significant amounts of the highly toxic hydrocyanic acid which must be removed before the oil can be used in flavors or perfumes. As little as 0.02 grams of this poison is lethal to the average human being. This amount of hydrocyanic acid can be present in about 8 to 10 drops of crude, unrectified **Bitter Almond Oil**. It is interesting to note that hydrocyanic acid has an odor which is somewhat similar to that of **Benzaldehyde**, the main constituent of bitter almond oil. The two chemicals have nothing in common with respect to chemical structure. Hydrocyanic acid is eliminated from the crude bitter almond oil by alkali washing and rectification. **Bitter Almond Oil **is a colorless liquid of strong, but sweet and clean odor, reminiscent of crushed, wet bitter almonds or of a very high grade of benzaldehyde (which it might well be!). The odor is also familiar to those who prepare or enjoy the European candy known as “**Marcipan**” (panis marci is Latin for “marcus’ loaf of bread”) or “**Almond Paste**”. This is probably an old Italian specialty, now a popular candy- and pastry-filling in many European countries. It is (or should be) made from mashed sweet almond kernels to which a few bitter almond kernels are added for flavor (less than 1% is sufficient). Old recipes also include rose water or orange flower water. The paste is worked up with icing sugar to a solid, slow-drying mass. Bitter **Almond **Oil, which is almost pure **Benzaldehyde, **is not a very stable oil. An addition of 10% (but not less) of ethyl alcohol is recommended as a stabilizer, and the oil should be stored in well filled glass containers, protected from daylight, moisture and air; the containers should be adjusted in size according to the rate of consumption of the contents. Crystals of benzoic acid will quickly appear around the cork as well as at the surface and the bottom of the container as soon as it has been opened just once. **Bitter Almond Oil **finds very little use in perfumery where it is replaced by a high grade of benzaldehyde (see below). Both materials are highly volatile and have no fixative effect at all. They blend well with anisic-balsamic types of odor, e.g. in lilac and other sweet florals. In flavors, it may be possible to tell the difference between a natural **Bitter Almond Oil **and a synthetic, high-grade **Benzaldehyde. **Bitter almond oil is a sweetener in apple, apricot, cherry, peach, pistachio, plum, raspberry, almond and countless other flavors. It is also used extensively in baked goods, candy, sugar fondants, etc., often without any other flavor material. However, a great deal of flavor is lost when the oil is used as such in baked goods. Fixatives, e. g. vanillin, anisic alcohol, benzaldehyde-phenylglycidates, etc. may greatly improve the tenacity and stability of the oil. The average use level in flavors is about *5 *to 8 mg%, while the Minimum Perceptible is about 1.0 to 1.5 mg%. It is worth noticing that the flavor is sweet, not bitter. The bitter taste produced from chewing bitter almond kernels is due to a non-volatile bitter principle which decomposes in aqueous media. **Bitter**** ****Almond**** ****Oil**** **is very rarely produced from bitter almonds. If the oil is a natural distillate at all, it is most often produced from other kernels (see above). A large part of all the so-called bitter almond oil in the market is actually a refined synthetic benzaldehyde, supposedly free from chlorine. The labelling FFPA stands for “free from prussic acid” (old name for hydrocyanic acid). The abbreviation FFC means “free from chlorine”, and is obviously applied to synthetic products. If the analyst finds chlorine in a sample of bitter almond oil, this may very well be solid proof that the oil is synthetic benzaldehyde, either wholly or partially. If he finds hydrocyanic acid, this finding could be an indication of natural origin of the oil. But, unfortunately, this may not always be so. The perfumers in the supply houses are clever too. The hydrocyanic acid traces may have been added deliberately to a chlorine-free synthetic benzaldehyde in order to make the imitation well-nigh perfect. In such cases, it is hardly possible to tell the difference, and it really makes no difference either. Benzaldehyde is, of course, considerably cheaper than true bitter almond oil. Other well-known “mono- component” oils are: Birch **Bark Oil,**** ****Winter-green Oil, Ho Leaf Oil, Ocotea Pretiosa Oil, **etc. In view of the fact that there are thousands of tons of kernels from apricots and other “canning” fruits available as a low-cost raw material after the hydraulic expression of the fixed oil, it is conceivable that the production of “true” bitter almond oil (from such de-oleated kernels) may continue in the future.