Recognition and identification of compounds contributing to off-flavor of egg white powder by molecular sensory science approach

Egg white powder (EWP) is a kind of food processing ingredient with high quality, low price and superior processing performance. However, its application in food industry is seriously affected by the problems such as strong off-flavor and its unknown volatile compounds. In this study, EWP was taken as the research object, and the off-flavor difference of EWP under different drying methods (spray drying, vacuum drying and freeze drying) was taken as the breakthrough point. With the help of gas chromatograph-mass spectrometer (GC–MS), electronic nose (E-nose) and sensory evaluation, it was found that the off-flavor of EWP was described as fishy and green, and high temperatures made the off-flavor worse, especially SD-EWP presented the strongest odor. A total of 13 key flavor compounds and 7 potential off-flavor compounds in SD-EWP were identified by gas chromatograph–mass spectrometer–olfactometry (GC-MS-O) and aroma reconstruction experiments. The relationship model of key flavor compounds, E-nose and off-flavor was established by multivariate analysis. It was verified that octanal, nonanal, 1-octen-3-ol and geranyl acetone were the off-flavor compounds of EWP. This study provided theoretical guidance and technical reference for the flavor research and sensory quality improvement of EWP.