Sensory-directed flavor analysis of off-flavor compounds in infant formula with deeply hydrolyzed milk protein and their possible sources

Off-flavor compounds in IF-DHMP were identified using sensory-directed analysis. In total, 56 types of aromaactive compounds were identified in the off-flavor (OF) samples, positive control (PC) samples, and accelerated oxidation (AO) samples. The Aroma Extraction Dilution Analysis (AEDA) results showed that methional, generated via Maillard reaction, was the most important component with the highest dilution factor in OF. The results of aroma recombination, omission and spiking experiment revealed that compounds such as pentanal, methional, (E)-2-nonenal, 3-methylbutanal, (E)-2-heptenal, nonanal, (E,E)-2,4-heptadienal, 1-penten-3-one, 1-octen-3-one, and (E,E)-2,4-nonadienal were the major sources of off-flavor in OF. We observed that the off-flavor in OF samples originated due to proteolysis, Maillard reaction, or lipid oxidation during processing rather than due to lipid oxidation during storage.