High-throughput screening of acetals/ketals in edible essences via GC-Orbitrap-MS and their formation rates at room temperature

Flavors contain active aldehydes and ketones that react with glycerol and propylene glycol to form acetals and ketals. The identification of acetals and ketals is challenging due to the incomplete information in mass spectral libraries. This study examines the reaction kinetics of 36 aldehydes and ketones with propylene glycol and glycerol, and establishes a high sensitivity and throughput screening method for 185 acetals and ketals using GCOrbitrap-MS. Formation rates of acetals and ketals at room temperature, and influencing factors like steric hindrance, boiling point, and molecular size were explored. A high-resolution mass spectrometry database was established through model reactions and 10 market-purchased edible essences were analyzed. The analysis of edible essences showed that the detected analytes closely correspond to aldehyde and ketone species prone to hydroxyl-aldehyde condensation reactions at room temperature. This method offers high sensitivity, throughput, and accuracy for rapid screening of acetals and ketals in essences.