Analysis of Volatile Compounds in Probiotic Yogurt during Storage through Solid-phase Microextraction Gas Chromatography

Two different yogurts, control and probiotic with Bifidobacterium BB-12 were produced and analyzed for their contents of total solids, proteins, pH, counts of probiotic bacteria, and volatile composition during refrigerated storage for 28 days. The response surface methodology (RSM) was used to optimize the extraction of volatile compounds from the probiotic yogurt containing through HS-SPME combined with gas chromatography–mass spectrometry (GC–MS). Post-acidification and decrease in protein content were noted in both yogurts during storage. The results showed that the extraction temperature and the addition of salt were statistically the most influential factors for the extraction of higher amounts of volatile compounds. The volatile compounds detected in the probiotic yogurt were 2-butanone, 2,3-butanedione, 2,3-pentanodione, acetone and hexanoic acid. During the 28 days of storage, the only differences noted were between the amounts of 2,3-butanedione, 2,3-pentanodione and hexanoic acid.