Professor Laura Cornara of Distav-University of Genoa and Dr. Giovanni Minuto of Cersaa in Albenga are engaged in research to analyze and recover some "historic" basil varieties from which the characteristics of Basilico Genovese DOP derive (OLD Basil project funded by the Liguria Region PSR M.10.2).
They told us the results of their research in this double interview.
When we rub a basil leaf between our fingers or crush it with a pestle, an aroma is released that permeates the air: why?
Prof. Cornara
: The pressure of our fingers or the pestle causes the rupture of microscopic glandular structures scattered across the leaf blade, resulting in the release of the fragrant essential oil.
What are the glandular structures to which we owe the precious aroma that characterizes basil made of?
Professor Cornara : On the basil leaf—and especially on its underside—there are many of these structures, the glandular hairs or trichomes, equipped with secretory cells. These glandular hairs are of two types: smaller, called ‘capitate’, and larger, called ‘peltate’ (which, being over 60 microns in diameter, can be identified even with a simple magnifying glass). The peltate hairs, which appear as rounded, translucent vesicles, are filled with essential oil, which gives the basil its characteristic aroma.
How does the release mechanism of this scented oil occur?
Professor Cornara : Basil typically has four secretory cells (unlike other Lamiaceae, such as sage and mint, which may have eight or more). These cells are topped by a thin cap that is filled with the essential oil they secrete… even a slight movement can cause them to open or break, thus dispersing the aroma.
But is the aroma of Genoese Basil DOP really different from that of other basil plants, even from a scientific point of view?
Professor Cornara:
Of course. As with every PDO, its unique characteristics, along with its territorial connection, are demonstrated through in-depth research and can be appreciated every day by consumers. In the case of Genoese Basil PDO, the composition of its essential oil is unique and influenced by the climate, soil, proximity to the sea, and cultivation and harvesting methods.
On what scientific basis can we state that the essential oil of our Genoese Basil DOP is particular and has unique characteristics?
Dr. Minuto:
Several tests have been conducted over time, comparing the essential oil and volatile compounds of Genoese basil from Liguria with those of basil plants grown in other Italian regions or even other parts of the Mediterranean. The results of the analyses showed that basil grown in Liguria always contains a high amount of a specific compound, trans-α-bergamotene. This compound, however, was always very low or almost absent in plants grown elsewhere. Conversely, plants grown in other regions frequently have a distinct mint aroma—pungent and unpleasant in pesto—which is always absent in our Genoese Basil DOP.
So how do we explain the different types of basil that are now very popular, with aromas of lemon, anise, cinnamon, spices, etc.?
Dr. Minuto:
The biodiversity present among the Lamiaceae family, to which basil belongs, and in particular within the Ocimum genus, is extraordinary. Numerous basil cultivars already exist in nature or have been specially improved to give pleasant aromas or particular colors to the foliage and stems, used by chefs to flavor salads, fruit salads, cocktails, etc., or to add a touch of color to dishes. The composition and quantity of essential oil secreted in their glandular hairs is actually very different from that which characterizes Genoese Basil DOP, as evidenced by phytochemical analyses. In some cases, these varieties of Ocimum basilicum , but also of Ocimum basilicum, are not only unique but also unique. . sanctum and O. gratissimum , are used for purposes other than culinary ones, in perfumery or cosmetics.
So in the case of Genoese Basil DOP, what effect do the Ligurian climate and soil, combined with the “human factor” of traditional cultivation developed in the area over decades, have?
Dr. Minuto
: These are all very important factors that contribute, without exception, to giving basil a different and unique aroma that arises from an original combination, both quantitatively and qualitatively, of the volatile substances and components of its essential oil, in which trans-α-bergamotene can never be missing.
