Screening of aroma‐producing lactic acid bacteria and their application in improving the aromatic profile of yogurt

Abstract

The development of yogurt flavor is a complicated and dynamic biochemical process. In addition to traditional starter cultures, adjunct cultures could also make significant contributions to the flavor profiles of yogurt. In the current study, two Lactobacillus plantarum strains (1‐33 and 1‐34) were isolated based on their abilities to produce acetaldehyde and diacetyl. In co‐fermentation with traditional starters, these isolated strains were able to maintain viability without affecting the yogurt’s acidification profiles. Furthermore, they positively influenced the aroma quality of the yogurt samples. They promoted the formation of volatile metabolites, especially acetaldehyde, diacetyl, and acetoin, which are recognized as characteristic compounds. The results of this work provide novel knowledge about the contributions of isolated strains on the flavor profiles of yogurt, which will help to improve the organoleptic properties of the final products. Practical applications Using lactic acid bacteria (LAB) as adjunct cultures co‐fermented with traditional yogurt starter cultures can increase the quantities of flavor compounds in yogurt. This study enriches our understanding of the effects of adjunct cultures on yogurt flavor. Researchers and manufacturers that specialize in yogurt making can use the results of this study to improve the aromatic profile and organoleptic quality of yogurt.

Evaluation of Volatile Compounds during the Fermentation Process of Yogurts by Streptococcus thermophilus Based on Odor Activity Value and Heat Map Analysis

“…2-dodecanone contributed an "orange, grass, fresh" odor in the 0, 1.5, and 3.0 h samples with 24, 28, and 34 OAVs that belonged to medium OAVs. Among the odor-active ketones, 2-heptone, 2-nonanone, and 2-undecanone contributed "fresh cream," "grass, fruity, floral," and "foam grass" odors to yogurt fermented by L. plantarum with medium OAVs [24]. 2-Decanone, which contributes a "fresh cream" odor, was identified as an odor-active compound in fermented camel milk [36].…”

“…e volatile components were identified by comparing their mass spectra to mass spectra from mass spectral libraries (NIST 05, WILEY 7.0) and to previously published data. ese volatiles were further confirmed by matching their linear retention indices (LRIs) and odor descriptions in the literature [3,24,25]. e LRIs were computed according to the following equation [26]:…”

“…In the 6.0 h sample, the OAVs of hexanoic acid, octanoic acid, undecanoic acid, dodecanoic acid, and tetradecanoic acid increased to 10-100 and had medium odor intensity, whereas the OAV of decanoic acid increased to 260 and had high odor intensity. Hexanoic acid and octanoic acid with characteristic of "spicy, rancidity" and "chess, sweaty" odors were detected as odor-active compounds in yogurt fermented by L. plantarum with Odor description and threshold were provided in references [3,24,25]. 6 International Journal of Analytical Chemistry medium OAVs [24].…”

“…Hexanoic acid and octanoic acid with characteristic of "spicy, rancidity" and "chess, sweaty" odors were detected as odor-active compounds in yogurt fermented by L. plantarum with Odor description and threshold were provided in references [3,24,25]. 6 International Journal of Analytical Chemistry medium OAVs [24]. Undecanoic acid, decanoic acid, dodecanoic acid, and tetradecanoic acid provide odors such as "fatty," "sweet," "floral," and "waxy" in dairy products such as fermented camel milk [36] and cheese [37].…”

“…It has been widely introduced to choose impact odorants in dairy product such as milk [ 17 , 18 ], milk power [ 19 , 20 ], and cheese [ 21 – 23 ]. Tian et al (2019) reported that odor characteristic components in yogurt are generated by L. plantarum fermentation using OAV and confirmed that diacetyl, 2-heptaone, and 2-nonanone are important odor components [ 24 ].…”