Volatile Flavor Compounds Profile and Fermentation Characteristics of Milk Fermented by Lactobacillus delbrueckii subsp. bulgaricus

Abstract

Lactobacillus delbrueckii subsp. bulgaricus is one of the predominant lactic acid bacterial species used as starter cultures in industrial fermented dairy manufacturing, as it strongly affects the quality of the products. Volatile flavor compound profiles and fermentation characteristics are considered to be the most important indicators for starter culture screening. In the present study, volatile compounds in milk fermented by 17 test strains of L. delbrueckii subsp. bulgaricus and a commercial strain used as a control were identified using solid-phase microextraction (SPME) methods coupled with gas chromatography mass spectrometry (GC-MS). In total, 86 volatile flavor compounds were identified in the fermented milk upon completion of fermentation, including 17 carboxylic acids, 14 aldehydes, 13 ketones, 29 alcohols, 8 esters, and 5 aromatic hydrocarbon compounds. Various volatile flavor compounds (acetaldehyde, 3-methyl-butanal, (E)-2-pentenal, hexanal, (E)-2-octenal, nonanal, 2,3-butanedione, acetoin, 2-heptanone, 2-non-anone, formic acid ethenyl ester) were identified due to their higher odor activity values (>1). In addition, of the 17 test strains of L. delbrueckii subsp. bulgaricus, IMAU20312 (B14) and IMAU62081 (B16) strains exhibited good fermentation characteristics in milk compared with the control strain. The combination of the volatile flavor compound profile and fermentation characteristics in this work could be useful when selecting lactic acid bacteria that may serve as important resources in the development of novel fermented milk products.

High biodiversity in a limited mountain area revealed in the traditional production of Historic Rebel cheese by an integrated microbiota–lipidomic approach

“…paracasei . In our study 2-Heptanol, derived by the reduction of the corresponding ketone, showed a strong positive correlation with Lactobacillus as found by Dan et al 37 , where this secondary alcohol was detected in samples fermented by different strains of Lactobacillus . Hexanal, a result of lipid oxidation, and its corresponding alcohol 1-hexanol, showed a strong positive correlation with Streptococcus, confirming the findings of Dan et al 38 where this compound was present in milk fermented by S. thermophilus.…”

“…6 . Among the total volatiles, most ethyl-esters, along with ethanol, are correlated with Leuconostoc, as observed by Pogačić et al 37 , confirming their potential combination as adjunct flavoring in cheese, associated with the development of fruity, sweet, and floral flavor notes, in particular in long ripened cheeses 30 . In our study the 3-Hydroxybutan-2-one (or acetoin, derived by citrate metabolism) is strongly and positively associated with Lactococcus genus , confirming the results of Pogačić et al 35 and of Gallegos et al 36 where 3-Hydroxybutan-2-one and 3-methylbutan-1-ol were positively correlated to L. rhamnosus, L. paracasei, L. sakei and L. lactis subsp lactis, L. lactis subsp.…”

Assessment of Growth and Technological Performances of Yogurt Bacteria Isolated From Local Turkish Yogurts

“…Diacetyl (2,3-butanedione), which is mainly responsible for the buttery flavor in foods, was more abundant in yogurts made by isolate LB2. The relatively higher abundance of carboxylic acids and ketones in single strain yogurts were reported by Dan et al [23] who screened 17 Lb. bulgaricus strains isolated from local fermented cow or yak milk products for volatile compounds profiles.…”

Enhanced Aromatic Profile and Functionality of Cheese Whey Beverages by Incorporation of Probiotic Cells Immobilized on Pistacia terebinthus Resin

“…Volatile compounds identified by solid-phase microextraction gas chromatography/mass spectrometry (SPME/GC-MS) in whey beverages (A2: 0.6 g of the immobilized biocatalyst per 100 mL of whey; B2: 0.6 g of Pistacia terebinthus resin per 100 mL of whey; C: control sample) after 30 days of storage (all values presented as percentage). [22,23,25,37,[67][68][69][70][71], RT: Positive identification by retention times that agrees with authentic compounds and by the mass spectra of authentic compounds generated in the laboratory, MS: tentative identification by mass spectra obtained from NIST107, NIST21, and SZTERP libraries, Nd: not detected, Tr: Traces (<0.1%).…”