Changes in Odor Compounds of a Lactobacillus-fermented Dairy Beverage during Two Weeks of Refrigerated Storage

Abstract

Lactobacillus paracasei MCC1849 (LP) has the potential to modulate immune function. To develop a functional LP-fermented dairy beverage, changes in intensities of odorants during two weeks of refrigerated storage were investigated by gas chromatography-olfactometry (GC-O, CharmAnalysis™). A fermented dairy beverage containing 1 × 10⁸ viable LP cells/mL, 0.8% non-fat milk solids, and 0.1% milk fat was prepared, and then stored at 10°C for 0, 1, or 2 weeks before solvent extraction. GC-O of the volatiles in the resulting extracts detected 34 odorants, of which 29 were identified. Among the identified compounds, 4-(4′-hydroxyphenyl)-2-butanone (raspberry ketone) was also detected by GC-mass spectrometry, representing the first identification of this compound as an odorant in fermented dairy products to our knowledge. Principal component analysis of the GC-O data permitted discrimination among the 3 stored samples according to duration of storage, and clarified the major odors contributing to the change in odor characteristics during storage.