[en] Odor is an essential characteristic and a quality marker in baby foodstuff, like a partially hydrolyzed and pregelatinized rice flour. The rice flour study by active sampling and TD-GC/MS highlighted the presence of three aldehydes: Hexanal, Octanal, Nonanal. These compounds are known to be caused by lipid oxidation, one of the major alteration reactions in food. The Method was developed and valited on a large range for the three aldehydes. It was then applied to the rice fllour to determine if it can be used to follow the effect of ageing on the aldehydes production.