Flavours and fragrances are associated with the major part of our daily activities. These substances are present in foods, beverages, toilette products, laundry powder and, of course, perfumes. This variety of possible applications prompted a great differentiation of the chemical components available on the market and rise up the economical relevance of the flavours industries. Moreover, the latter companies have recently directed theirs efforts towards the synthesis of more effective, more specific and biodegradable compounds that could be used in a small amount. This general trend is due to the increasing environmental sensitivity that suggests a reduction of the chemicals wasted. Concerning the creation of new flavours, the chemical researches hold a pivotal role since they are necessary either for the improvement of the synthetic steps or for the qualitative development of the final products. Indeed, these latter are often complex isomeric mixtures and each component might show different olfactory features whose organoleptic evaluation is related to the specific preparation of every single isomer.
In this area our Institute is engaged both in the creation of new synthetic methods and in the stereospecific preparation of flavours and fragrances. This kind of work needed the synergical employment of several skills and technical knowledge. For instance, we used both asymmetrical synthesis and biocatalysis in order to prepare enantiopure olfactorily active compounds and spectroscopic measurements for the determination of the molecular structure of these compounds. Specifically, we obtained noteworthy results in the field of the natural products of terpenic origin (monoterpenes, norterpenoids, sesquiterpenes) and also in the synthesis of oxygenated heterocycles systems. A relevant project consisted in the enantiospecific preparation of irons. The latter compounds are norterpenoids that have been used over the century as violet flavour in fine perfume formulation. Irons are extracted from iris roots and, although they are very expensive, these natural products are still used since give better performances if compared with the corresponding synthetic material. Thank to the use of chemical synthesis and enzymes mediated processes we were able to prepare all the isomeric forms of irons. The following olfactory evaluation performed by expert perfurmers showed that the organoleptic differences between the isomers are significant enough to describe the dissimilarity between natural and synthetic product. These results consent the creation of a new synthetic formulation identical (or qualitatively superior) to the natural one.
The study described above and others similar allowed to the researchers of our Institute to acquire new knowledge in the field of flavours and fragrances and to develop new synthetic methods of scientific and industrial relevance. Moreover, these activities afforded a continuous exchange of information between academic and industrial organisations.
The research was achieved thank to the co-operation with the 'Politecnico di Milano' and companies working in the flavours and fragrances production. The studies have been granted by CNR and MIUR.
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