Supercritical CO2 extraction method of aromatic compounds from truffles

Truffles are a well-known worldwide product mainly appreciated by their unique aroma, which is composed by more than 50 volatile compounds. However, to this day, no one has accomplished to find the aromatic key that evokes the real aroma of truffles for its use as food flavoring. Among them, black truffle was selected for extraction with supercritical fluids using CO2 as solvent recovering natural truffle aroma fraction. To achieve the optimal extraction ratio, time, pressure and grapeseed oil addition to the separators were evaluated. Aroma from black truffle powder, extracts obtained, and residual cakes fractions were characterized by headspace gas chromatography-spectrometry and olfactometry techniques. The results indicated that optimal extraction conditions were 30 MPa for 3 h. Also, grapeseed oil addition enhanced trapping some key truffle aromatic compounds as 2,3-butanodione, 2-methyl-1-butanol, octanal and dimethyl disulphide. Olfactometry study showed the aromatic profile of the extracts indicating the molecules ethyl pentanoate (fruity), 1-hexen-3-one (metallic) and ethyl hexanoate (fruity) as the main compounds of extracts samples. For the first time, a natural truffle aroma has been obtained using low-value truffles. After aromatic extraction, carbohydrates, proteins, and phenolic compounds were analysed within the residues, showing a potential source of bioactive compounds.