LC-MS Study To Reduce Ion Suppression and To Identify N-Lactoylguanosine 5'-Monophosphate in Bonito: A New Umami Molecule?

摘要

In this study a specific taste modulating flavor ingredient, N-lactoylguanosine 5'-monophosphate (N-lactoyl GMP), was determined in bonito (Japanese, Katsuobushi, dried fermented skipjack) and in powdered bonito using liquid chromatography-electrospray ionization (+) mass spectrometry-mass spectrometry (LC-ESI(+)-MS/MS) with a methanol/ammonium acetate or formate gradient. Furthermore, the influence of ion suppression due to sample matrix effect was investigated and was found to substantially influence the total MS response of N-lactoyl GMP; by adjusting the LC conditions the response could be approximately 5-fold-enhanced. The N-lactoyl GMP concentrations in different types of bonito products were between 0.2 and 2.4 mug/g. Keywords: Mass spectrometry; bonito; N-lactoylguanosine 5'-monophosphate; flavor; liquid chromatography; umami; triple quadrupole; ion suppression.