Real-Time Flavor Release from French Fries Using Atmospheric Pressure Chemical Ionization-Mass Spectrometry

Flavor release from French fries was measured with atmospheric pressure chemical ionization-mass spectrometry (APCI-MS) using both assessors (in vivo) and a mouth model system (in vitro). Several volatiles measured with APCI were identified with MS-MS. The effect of frying time, salt addition, and an alternative process using superheated steam was determined on Imax (maximum intensity of compounds) and on tmax (time of maximum intensity). In vitro a "chewing" frequency of 0.60 Hz caused an increased tmax for low molecular weight compounds compared to the other frequencies tested. Above 0.93 Hz further increase in the frequency did not affect tmax. Trends observed with in vivo experiments could be verified with in vitro experiments. Imax correlated well with frying time. Addition of salt resulted in a decreased tmax, suggesting a salting-out effect. The alternative process caused a layer of oil on the surface, and this resulted in a higher tmax, but no effect on Imax was found. This phenomenon may be critical for the sensory quality and would not have been observed with static volatile measurements, demonstrating the value of flavor release measurements