scholarly journals Effect of starter culture and inulin addition on microbial viability, texture, and chemical characteristics of whole or skim milk Kefir

2012 ◽  
Vol 32 (4) ◽  
pp. 580-865 ◽  
Author(s):  
Flávia Daiana Montanuci ◽  
Tatiana Colombo Pimentel ◽  
Sandra Garcia ◽  
Sandra Helena Prudencio

The effect of inulin addition and starters (Kefir grains or commercial starter culture) on the microbial viability, texture, and chemical characteristics of Kefir beverages prepared with whole or skim milk was evaluated during refrigerated storage. The type of starter did not influence microbial viability during the storage of the beverages, but the chemical and textural changes (decreases in pH, lactose concentration, and inulin and increased acidity, firmness, and syneresis) were more pronounced in the formulations fermented with grains than those fermented with the starter culture. The addition of inulin did not influence acidity or viability of lactic acid bacteria, but in general, its effect on the survival of acetic acid bacteria, Lactococcus and yeasts, firmness, and syneresis depended on the type of milk and starter culture used. Generally, the yeast, acetic acid bacteria, and Leuconostoc counts increased or remained unchanged, while the total population of lactic acid bacteria and Lactococcus were either reduced by 1 to 2 logs or remained unchanged during storage.

2010 ◽  
Vol 76 (23) ◽  
pp. 7708-7716 ◽  
Author(s):  
Timothy Lefeber ◽  
Maarten Janssens ◽  
Nicholas Camu ◽  
Luc De Vuyst

ABSTRACT The composition of cocoa pulp simulation media (PSM) was optimized with species-specific strains of lactic acid bacteria (PSM-LAB) and acetic acid bacteria (PSM-AAB). Also, laboratory fermentations were carried out in PSM to investigate growth and metabolite production of strains of Lactobacillus plantarum and Lactobacillus fermentum and of Acetobacter pasteurianus isolated from Ghanaian cocoa bean heap fermentations, in view of the development of a defined starter culture. In a first step, a selection of strains was made out of a pool of strains of these LAB and AAB species, obtained from previous studies, based on their fermentation kinetics in PSM. Also, various concentrations of citric acid in the presence of glucose and/or fructose (PSM-LAB) and of lactic acid in the presence of ethanol (PSM-AAB) were tested. These data could explain the competitiveness of particular cocoa-specific strains, namely, L. plantarum 80 (homolactic and acid tolerant), L. fermentum 222 (heterolactic, citric acid fermenting, mannitol producing, and less acid tolerant), and A. pasteurianus 386B (ethanol and lactic acid oxidizing, acetic acid overoxidizing, acid tolerant, and moderately heat tolerant), during the natural cocoa bean fermentation process. For instance, it turned out that the capacity to use citric acid, which was exhibited by L. fermentum 222, is of the utmost importance. Also, the formation of mannitol was dependent not only on the LAB strain but also on environmental conditions. A mixture of L. plantarum 80, L. fermentum 222, and A. pasteurianus 386B can now be considered a mixed-strain starter culture for better controlled and more reliable cocoa bean fermentation processes.


2007 ◽  
Vol 73 (6) ◽  
pp. 1809-1824 ◽  
Author(s):  
Nicholas Camu ◽  
Tom De Winter ◽  
Kristof Verbrugghe ◽  
Ilse Cleenwerck ◽  
Peter Vandamme ◽  
...  

ABSTRACT The Ghanaian cocoa bean heap fermentation process was studied through a multiphasic approach, encompassing both microbiological and metabolite target analyses. A culture-dependent (plating and incubation, followed by repetitive-sequence-based PCR analyses of picked-up colonies) and culture-independent (denaturing gradient gel electrophoresis [DGGE] of 16S rRNA gene amplicons, PCR-DGGE) approach revealed a limited biodiversity and targeted population dynamics of both lactic acid bacteria (LAB) and acetic acid bacteria (AAB) during fermentation. Four main clusters were identified among the LAB isolated: Lactobacillus plantarum, Lactobacillus fermentum, Leuconostoc pseudomesenteroides, and Enterococcus casseliflavus. Other taxa encompassed, for instance, Weissella. Only four clusters were found among the AAB identified: Acetobacter pasteurianus, Acetobacter syzygii-like bacteria, and two small clusters of Acetobacter tropicalis-like bacteria. Particular strains of L. plantarum, L. fermentum, and A. pasteurianus, originating from the environment, were well adapted to the environmental conditions prevailing during Ghanaian cocoa bean heap fermentation and apparently played a significant role in the cocoa bean fermentation process. Yeasts produced ethanol from sugars, and LAB produced lactic acid, acetic acid, ethanol, and mannitol from sugars and/or citrate. Whereas L. plantarum strains were abundant in the beginning of the fermentation, L. fermentum strains converted fructose into mannitol upon prolonged fermentation. A. pasteurianus grew on ethanol, mannitol, and lactate and converted ethanol into acetic acid. A newly proposed Weissella sp., referred to as “Weissella ghanaensis,” was detected through PCR-DGGE analysis in some of the fermentations and was only occasionally picked up through culture-based isolation. Two new species of Acetobacter were found as well, namely, the species tentatively named“ Acetobacter senegalensis” (A. tropicalis-like) and “Acetobacter ghanaensis” (A. syzygii-like).


Author(s):  
O.G.G. Almeida ◽  
E.C.P De Martinis

Metagenomic studies about cocoa fermentation have mainly reported on the analysis of short reads for determination of Operational Taxonomic Units. However, it is also important to determine MAGs, which are genomes deriving from the assembly of metagenomics. For this research, all the cocoa metagenomes from public databases were downloaded, resulting in five datasets: one from Ghana and four from Brazil. Besides, in silico approaches were used to describe putative phenotypes and metabolic potential of MAGs. A total of 17 high-quality MAGs were recovered from these microbiomes, as follows: (i) fungi - Yamadazyma tenuis (n=1); (ii) lactic acid bacteria - Limosilactobacillus fermentum (n=5), Liquorilactobacillus cacaonum (n=1) , Liquorilactobacillus nagelli (n=1), Leuconostoc pseudomesenteroides (n=1) and Lactiplantibacillus plantarum subsp. plantarum (n=1); (iii) acetic acid bacteria - Acetobacter senegalensis (n=2) and Kozakia baliensis (n=1) and (iv) Bacillus subtilis (n=1) Brevundimonas sp. (n=2) and Pseudomonas sp. (n=1). Medium-quality MAGs were also recovered from cocoa microbiomes, including some detected for the first time in this environment ( Liquorilactobacillus vini , Komagataeibacter saccharivorans and Komagataeibacter maltaceti ) and other previously described ( Fructobacillus pseudoficulneus and Acetobacter pasteurianus ). Taken all together, the MAGs were useful to provide an additional description of the microbiome of cocoa fermentation, revealing previously overlooked microorganisms, with prediction of key phenotypes and biochemical pathways. Importance The production of chocolate starts with the harvesting of cocoa fruits and the spontaneous fermentation of the seeds, in a microbial succession that depends on yeasts, lactic acid bacteria and acetic acid bacteria in order to eliminate bitter and astringent compounds present in the raw material, which will be further roasted and grinded to originate the cocoa powder that will enter the food processing industry. The microbiota of cocoa fermentation is not completely know, and yet it advanced from culture-based studies to the advent of Next Generation DNA sequencing, with the generation of a myriad of data, that need bioinformatic approaches to be properly analysed. Although the majority metagenomic of studies have been based on short reads (OTUs), it is also important to analyse entire genomes to determine more precisely possible ecological roles of different species. Metagenome-assembled genomes (MAGs) are very useful for this purpose, and in this paper, MAGs from cocoa fermentation microbiomes were described, as well the possible implications of their phenotypic and metabolic potentials are discussed.


2020 ◽  
Vol 8 (9) ◽  
pp. 1266 ◽  
Author(s):  
Łukasz Łopusiewicz ◽  
Emilia Drozłowska ◽  
Alicja Tarnowiecka-Kuca ◽  
Artur Bartkowiak ◽  
Kinga Mazurkiewicz-Zapałowicz ◽  
...  

This study aimed at investigating the antioxidant activity, oxidative stability, physicochemical and microbial changes of innovative vegan Camembert-analogue based on flaxseed oil cake (FOC) which was produced using lactic acid bacteria (LAB), mold Penicillium camemberti (PC) and yeast Geotrichum candidum (GC). Two variants were prepared, namely with LAB + PC and LAB + PC + GC. After fermentation for 24 h at room temperature, the samples were stored for 14 days at 12 °C and maturated for 14 days at 6 °C. Changes in microbial population, polyphenolics, flavonoids, radical scavenging capacity were evaluated. Additionally, textural changes, pH, acidity, levels of proteins, free amino acids, reducing sugars, oil content and its oxidative stability were determined. Results showed that LAB as well as fungi were capable of growing well in the FOC without any supplementation and the products were characterized by a high antioxidant potential (high polyphenolics and flavonoids contents as well as 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), superoxide (O2−) and hydroxyl (·OH) radicals scavenging activity). This study has demonstrated that bioactivity as well as the physicochemical properties depend on the starter culture used. Due to functional and biochemical characteristics conferred to the obtained Camembert-analogues, the use of P. camemberti and G. candidum showed a potential for industrial application. There is a potential for these products to be used where non-dairy alternatives are desired.


2014 ◽  
Vol 35 (1) ◽  
pp. 102-107 ◽  
Author(s):  
Dong-Hyeon Kim ◽  
Jung-Whan Chon ◽  
Hyunsook Kim ◽  
Hong-Seok Kim ◽  
Dasom Choi ◽  
...  

Food Control ◽  
2015 ◽  
Vol 50 ◽  
pp. 613-619 ◽  
Author(s):  
A. García-Ruiz ◽  
J. Crespo ◽  
J.M. López-de-Luzuriaga ◽  
M.E. Olmos ◽  
M. Monge ◽  
...  

2011 ◽  
Vol 77 (18) ◽  
pp. 6694-6698 ◽  
Author(s):  
Timothy Lefeber ◽  
Maarten Janssens ◽  
Frédéric Moens ◽  
William Gobert ◽  
Luc De Vuyst

ABSTRACTAmong various lactic acid bacterial strains tested, cocoa-specific strains ofLactobacillus fermentumwere best adapted to the cocoa pulp ecosystem. They fermented glucose to lactic acid and acetic acid, reduced fructose to mannitol, and converted citric acid into lactic acid and 2,3-butanediol.


2014 ◽  
Vol 80 (15) ◽  
pp. 4702-4716 ◽  
Author(s):  
Philipp Adler ◽  
Lasse Jannis Frey ◽  
Antje Berger ◽  
Christoph Josef Bolten ◽  
Carl Erik Hansen ◽  
...  

ABSTRACTAcetic acid bacteria (AAB) play an important role during cocoa fermentation, as their main product, acetate, is a major driver for the development of the desired cocoa flavors. Here, we investigated the specialized metabolism of these bacteria under cocoa pulp fermentation-simulating conditions. A carefully designed combination of parallel13C isotope labeling experiments allowed the elucidation of intracellular fluxes in the complex environment of cocoa pulp, when lactate and ethanol were included as primary substrates among undefined ingredients. We demonstrate that AAB exhibit a functionally separated metabolism during coconsumption of two-carbon and three-carbon substrates. Acetate is almost exclusively derived from ethanol, while lactate serves for the formation of acetoin and biomass building blocks. Although this is suboptimal for cellular energetics, this allows maximized growth and conversion rates. The functional separation results from a lack of phosphoenolpyruvate carboxykinase and malic enzymes, typically present in bacteria to interconnect metabolism. In fact, gluconeogenesis is driven by pyruvate phosphate dikinase. Consequently, a balanced ratio of lactate and ethanol is important for the optimum performance of AAB. As lactate and ethanol are individually supplied by lactic acid bacteria and yeasts during the initial phase of cocoa fermentation, respectively, this underlines the importance of a well-balanced microbial consortium for a successful fermentation process. Indeed, AAB performed the best and produced the largest amounts of acetate in mixed culture experiments when lactic acid bacteria and yeasts were both present.


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