Vanilla Extract

#### Vanilla Extract. It is interesting to see that the United States Pharmacopoeia uses glycerine, water and ethyl alcohol as a menstruum for extraction in the preparation of "pure vanilla extract". The surprising thing is that vanillin with glycerine forms an alcohol-insoluble condensation product. The author has no explanation for this contradiction. Under the monographs of **Vanilla Absolute, Vanilla "Resinoid" **and **Vanilla Tincture**, it is mentioned that a hydro-alcoholic extraction of the cured vanilla fruits is the method that yields the best and richest extract from an odor-flavor point of view. It is quite possible that, during the treatment with hot ethyl alcohol and water, certain chemical processes take place among the components of vanilla (transesterification, hydrolysis, etc.). Since the cured vanilla contains some oily and resinous matter, the most practical method of total extraction is the following: The vanilla is extracted once with petroleum ether or dichioromethane. This extract is evaporated per se, and kept separate till later. Extraction is then continued with 70% ethyl alcohol, then with 60% alcohol, with 50% alcohol and perhaps with 40% or 30% alcohol. Finally, one extract is made with hot, distilled water. The alcoholic extractions are carried out under one hour reflux, or they may be simple percolations. The water extraction is usually a percolation whereby adherent alcohol is flushed out of the exhaust plant material. The combined extracts are evaporated gently. Towards the end of alcohol take-off, propylene glycol is added to the extract so that the water can be distilled off under gentle vacuum (pot temperature about 40°C.). It is adviseable to extract the distillation water with petroleum ether since traces of delicate aromatic matter are steam distilled with the water. By weighing the completely exhausted and dried vanilla, it is possible to calculate the exact amount of non-aqueous extracted matter. The water content in the vanilla fruits prior to extraction must be determined in advance. Thus, it is possible to add exactly the right amount of propylene glycol so that the resulting extract is e.g. 1 = 1. At this point, the first petroleum ether extract is added or an alcohol extract from it is prepared and added. The extract from the distillation water is also added here. In other words, one part of extract corresponds to one part of vanilla. This preparation is a dark brown viscous liquid, and it is truly a "**Ten-fold Vanilla**** ****Extract**" in commercial (American) terms (see monograph on **Vanilla**** ****Tincture**). The extract will inevitably separate small amounts of oily liquid after standing or cool storage. This oil can be separated without significant loss of extract or flavor. The clarified extract is primarily a flavor material since it is not miscible with essential oils or most synthetic perfume materials. The miscibility could be improved by the use of triethylene glycol, heptylene glycol, hexylene glycol or triacetin in place of propylene glycol. However, such preparations would be banned from use in flavors in most countries.