This study combined gas chromatography-mass spectrometry (GC-MS) and odor activity value (OAV) assessments to analyze the volatile ingredient changes in formula powder during 11 months of storage at room temperature. Orthogonal partial least squares-discriminant analysis (OPLS-DA) and variable importance in projection (VIP) were also used to assess the potential indicators of aroma changes during storage. The aim was to expose the possible changes in the aroma profile and the substances that alter infant formula (IF) aroma during storage. The results showed that the aldehyde and ketone content in the milk formula increased as the storage time was extended, while the lactone and terpenoid levels decreased significantly. The OAV indicated the presence of various major aromatic substances at different storage times. Considering consumer concern regarding product flavor, this study ascertained that monitoring substance changes during storage showed that 2-heptanone was a good indicator of milk flavor, dimethyl disulfide was a suitable indicator of protein degradation, and 3-methylbutanal, heptanal, hexanal, pentanal, and octanal were all good indicators of fat oxidation. The results of previous related studies were used to supplement the data in this work regarding the changes in IF during product shelf life and to provide support for controlling the flavor substances and quality during new product development.
Keywords: GC-MS; Infant formula; OPLS-DA; Storage life; Volatile flavor compounds.
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