Adulteration in Rose oil

The genus Rosa Linn. (Rosaceae) is widely distributed in the temperate parts of the northern hemisphere and on tropical mountains. About 20 species and hundreds of varieties have been recorded in India in wild state and many have been introduced for cultivation as ornamentals. Mostly hybrid varieties exhibit a marked fragrance and are suitable for the extraction of Rose water and Rose oil (attar). The aroma referred to by perfumes as rose odour is found exclusively in the roses belonging to the so-called Centifolia group of family Rosaceae. Rose oil is light yellow in colour, when cooled it congeals to a translucent soft mass, having congealing point between 15 degrees and 22 degrees. The composition of rose oil is not uniform, the variation being due to a number of influences, the chief being the kind of flower and the place where it grows. The rose oil from plants grown in colder climates contain Being one of the most highly priced essential oils, rose oil has been subjected to adulteration. Formerly adulteration was carried out in a somewhat crude way, by addition of palmarosa oil, guaiac wood oil and spermaceti – the latter to simulate a normal stearoptene content in the adulterated oil. Such conditions can be detected by careful analysis. Today, however, rose oil is often sophisticated in a very clever manner and the analyst may be faced with considerable difficulties in finding the adulterants. The adulterator now has to his disposal a number of natural isolates of lower priced essential oils. The most important of these are geraniol and rhodinol (l-citronellol). If added in moderate quantities, these compounds cannot be detected in rose oil by mere routine analysis. In such cases, the analyst will have to rely upon careful olfactory tests which require much training and experience on a thorough chemical examination of the suspected oil. This then needs to be analyzed on GC-MS for trace analysis of adulterants.