Method of separation of major off-odor component and change of components of Gastrodia elata Blume fermented by lactic acid bacteria

Gastrodia elata Blume often has been used for the treatment of headache, convulsions, hypertension and neurodegenerative diseases. The main active ingredients are gastrodin, 4-hydroxybenzyl alcohol, vanillyl alcohol, 4-hydroxybenzylaldehyde and parshin A, B, C, E. But Gastrodia elata has these unpleasant tastes and odors which are mainly caused by ρ-cresol (4-methylphenol) and butanal. For this reason, there is a need to reduce off-odor of Gastrodia elata as well as improve utilization as functional food materials using fermentation. This study found the method of separation of major off-odor component (p-cresol) of Gastrodia elata using various lactic acid bacteria. Methods to separate p-cresol known as the off-odor component of Gastrodia elata were as follows. First, the volatile component extracted by simultaneous steam distillation and extraction (SDE) followed by silica chromatography with n-pentane: diethyl ether as solvent fraction was used. For flavor test result on each fraction, strong off-odor, strong swine barn-like in n-pentane:diethyl ether (20:80) extraction fraction was attributed to p-cresol of Gastrodia elata through GC and GC-MS. In result of analysis of p-cresol of fermented Gastrodia elata, when fermented by Lactobacillus. sakei for 2 days reduced to up 54.7% compared with an unfermented sample. The parishin derivatives of Gastrodia elata were analyzed by HPLC to investigate change of them during fermentation of Gastrodia elata by lactic acid bacteria. Compared with the parishin derivatives of an unfermented Gastrodia elata, those of fermented Gastrodia elata by Lactobacillus. sakei were increased up to 18.3% for 2 days.