Variation of Aroma Components of Pasteurized Yogurt with Different Process Combination before and after Aging by DHS/GC-O-MS

Abstract

Pasteurized yogurt is a healthy yogurt that can be stored in ambient temperature conditions. Dynamic headspace sampling (DHS) combined with gas chromatography-olfactory mass spectrometry (GC-O-MS), sensory evaluation, electronic nose (E-nose), and partial least squares discriminant analysis (PLS-DA) were used to analyze the flavor changes of pasteurized yogurt with different process combinations before and after aging. The results of odor profiles showed that the sensory descriptors of fermented, sweet, and sour were greatly affected by different process combinations. The results of odor-active compounds and relative odor activity value (r-OAV) showed that the combination of the production process affected the overall odor profile of pasteurized yogurt, which was consistent with the sensory evaluation results. A total of 15 odor-active compounds of 38 volatile compounds were detected in pasteurized yogurt samples. r-OAV results revealed that hexanal, (E)-2-octenal, 2-heptanone, and butanoic acid may be important odor-active compounds responsible for off-odor in aged, pasteurized yogurt samples. PLS-DA and variable importance of projection (VIP) results showed that butanoic acid, hexanal, acetoin, decanoic acid, 1-pentanol, 1-nonanal, and hexanoic acid were differential compounds that distinguish pasteurized yogurt before and after aging.

Fermentation Characteristics of Fermented Milk with Streptococcus thermophilus CICC 6063 and Lactobacillus helveticus CICC 6064 and Volatile Compound Dynamic Profiles during Fermentation and Storage

“…The production of 2,3-butanedione and 2,3-pentanedione is a result of the chemical decarboxylation of their precursors, 2-acetolactate and 2-aceto-2-hydroxybutyrate. Acetoin, 2,3-butanedione, and 2,3-pentanedione, which are considered important odor compounds in yogurt, showed the highest levels in the samples, consistent with the findings of this study [ 43 ]. The stability of 2, 3-pentanedione and acetoin remains unchanged throughout fermentation and storage, as shown in Figure 5 , indicating a potential enzymatic reduction of acetoin from 2, 3-pentanedione by diacetyl reductase [ 44 ].…”

Identification of key aroma‐active compounds in long shelf‐life yoghurt and milk produced by different pre‐sterilisation processes of raw milk using SBSE‐GC × GC–O–MS

“…Zhao et al . (2023) studied the aroma composition of pasteurised yoghurt with different fermentations combined with homogenisation and smooth pump processes. Thus, these studies underscore the impact of the production processes on the volatile flavour compounds of yoghurt and milk.…”