extraction Sample preparation and extraction was performed according to the modification of the method described in [25–27]. In short,80 mL of water Milli Q, 0.5 g of gluconolacton and 50 L of inter-nal standard n-heptanol (100 mg/L) were added to 30 g of deepfrozen sample powder. Homogenisation with ultra-turrax was per-formed at 21000 rpm for 3 min and followed by centrifugation at 21,000 rpm at 5◦C for 5 min. Supernatant was recovered andcentrifuged again for 10 min and filtrated through rapid paper filter. The solution was brought to an exact volume of 110 mL with milli Q water. Solid phase extraction was performed using ENV+ car-tridges, 1 g (Biotage, Sweden). The cartridge was pre-conditioned with 15 mL methanol followed by 20 mL of water. The aqueous extract was loaded onto the cartridge, which was then washed with 15 mL of water. The free aromatic compounds were eluted from the cartridge with 30 mL dichloromethane and the boundaromatic compounds (i.e. the glycosides) with 30 mL of methanol.60 mL of pentane was added to the dichloromethane fraction. The concentration steps were performed as described in [