Characterization of volatiles in garlic and in exhaled breath after garlic ingestion by on-line atmospheric pressure photoionization quadrupole time-of-flight mass spectrometry

Abstract

Through the use of on-line atmospheric pressure photoionization quadrupole time-of-flight mass spectrometry (APPI-QTOFMS), 32 volatiles from garlic were tentatively identified, and 9 metabolites were observed in exhaled breath after garlic ingestion. Methional and 3-methylthiopropionic acid, which may reflect the metabolism of methionine from garlic, were observed in garlic breath for the first time. Variation of metabolites was also monitored within 1 h to show the metabolic processes. The signal intensity of methional, 3-methylthiopropionic acid and p-cymene was increased within 35 min and then declined. Other 6 metabolites including allyl mercaptan, allyl methyl sulfide, diallyl sulfide, allyl methyl disulfide, diallyl disulfide and dimethyl selenide reached maxima shortly after ingestion of garlic and declined continuously. Our result indicates that APPI-QTOFMS is potential for investigation of food metabolism in dynamic via exhaled breath.