scholarly journals The Type and Concentration of Inoculum and Substrate as Well as the Presence of Oxygen Impact the Water Kefir Fermentation Process

2021 ◽  
Vol 12 ◽  
Author(s):  
David Laureys ◽  
Frédéric Leroy ◽  
Tom Hauffman ◽  
Marc Raes ◽  
Maarten Aerts ◽  
...  

Eleven series of water kefir fermentation processes differing in the presence of oxygen and the type and concentration of inoculum and substrate, were followed as a function of time to quantify the impact of these parameters on the kinetics of this process via a modeling approach. Increasing concentrations of the water kefir grain inoculum increased the water kefir fermentation rate, so that the metabolic activity during water kefir fermentation was mainly associated with the grains. Water kefir liquor could also be used as an alternative means of inoculation, but the resulting fermentation process progressed slower than the one inoculated with water kefir grains, and the production of water kefir grain mass was absent. Substitution of sucrose with glucose and/or fructose reduced the water kefir grain growth, whereby glucose was fermented faster than fructose. Lacticaseibacillus paracasei (formerly known as Lactobacillus paracasei), Lentilactobacillus hilgardii (formerly known as Lactobacillus hilgardii), Liquorilactobacillus nagelii (formerly known as Lactobacillus nagelii), Saccharomyces cerevisiae, and Dekkera bruxellensis were the main microorganisms present. Acetic acid bacteria were present in low abundances under anaerobic conditions and only proliferated under aerobic conditions. Visualization of the water kefir grains through scanning electron microscopy revealed that the majority of the microorganisms was attached onto their surface. Lactic acid bacteria and yeasts were predominantly associated with the grains, whereas acetic acid bacteria were predominantly associated with the liquor.

2014 ◽  
Vol 80 (8) ◽  
pp. 2564-2572 ◽  
Author(s):  
David Laureys ◽  
Luc De Vuyst

ABSTRACTWater kefir is a sour, alcoholic, and fruity fermented beverage of which the fermentation is started with water kefir grains. These water kefir grains consist of polysaccharide and contain the microorganisms responsible for the water kefir fermentation. In this work, a water kefir fermentation process was followed as a function of time during 192 h to unravel the community dynamics, the species diversity, and the kinetics of substrate consumption and metabolite production. The majority of the water kefir ecosystem was found to be present on the water kefir grains. The most important microbial species present wereLactobacillus casei/paracasei,Lactobacillus harbinensis,Lactobacillus hilgardii,Bifidobacterium psychraerophilum/crudilactis,Saccharomyces cerevisiae, andDekkera bruxellensis. The microbial species diversities in the water kefir liquor and on the water kefir grains were similar and remained stable during the whole fermentation process. The major substrate, sucrose, was completely converted after 24 h of fermentation, which coincided with the production of the major part of the water kefir grain polysaccharide. The main metabolites of the fermentation were ethanol and lactic acid. Glycerol, acetic acid, and mannitol were produced in low concentrations. The major part of these metabolites was produced during the first 72 h of fermentation, during which the pH decreased from 4.26 to 3.45. The most prevalent volatile aroma compounds were ethyl acetate, isoamyl acetate, ethyl hexanoate, ethyl octanoate, and ethyl decanoate, which might be of significance with respect to the aroma of the end product.


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).


2017 ◽  
Vol 9 (2) ◽  
pp. 50-54
Author(s):  
Murna Muzaifa ◽  
Yusya Abubakar ◽  
Faitzal Haris

Fermentation process is the most crucial step in the formation of the flavor and aroma of the cocoa bean. Cocoa bean fermentation triggers an array of chemical changes within the bean.These chemical changes are vital to the development of the complex and much-loved flavour known as “chocolate”. Fermentation involves a number of specific microorganisms that play a role during fermentation. The aim of this research was to analized microorganism growth profil of Aceh cacao during fermentation. Fermentation was conducted on 6 days with  different aerations (agitation every 24 and 48 hours). The result showed that growth profile of microorganism during fermentation relatively  had similar trend. Yeast dominated on the early fermentation, lactid bacteria reached the higest population on day 3 and acetic acid bacteria on day 4. Better quality of fermented cacao was resulted on every 48 hours of agitation  that reached 70,19% of full fermentation.


2020 ◽  
Vol 8 (2) ◽  
pp. 192 ◽  
Author(s):  
Fatemeh Nejati ◽  
Stefan Junne ◽  
Peter Neubauer

Milk kefir is a traditional fermented milk product whose consumption is becoming increasingly popular. The natural starter for kefir production is kefir grain, which consists of various bacterial and yeast species. At the industrial scale, however, kefir grains are rarely used due to their slow growth, complex application, bad reproducibility and high costs. Instead, mixtures of defined lactic acid bacteria and sometimes yeasts are applied, which alter sensory and functional properties compared to natural grain-based milk kefir. In order to be able to mimic natural starter cultures for authentic kefir production, it is a prerequisite to gain deep knowledge about the nature of kefir grains, its microbial composition, morphologic structure, composition of strains on grains and the impact of environmental parameters on kefir grain characteristics. In addition, it is very important to deeply investigate the numerous multi-dimensional interactions among different species, which play important roles on the formation and the functionality of grains.


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

2018 ◽  
Vol 8 (8) ◽  
pp. 367 ◽  
Author(s):  
Funda Davras ◽  
Zeynep Banu Guzel-Seydim ◽  
Tugba Kok Tas

Background: Natural kefir grains have a unique microbiota. The structure contains lactic acid bacteria (LAB), acetic acid bacteria and yeast in specific ratios in a polysaccharide matrix. Authentic kefir is produced by a traditional method using kefir grains cultured in milk. In contrast, starter cultures are used instead of kefir grains in the industry. The commercial kefir starter cultures used are limited and often very different from the kefir grain microbiota.  The resultant commercial “kefir” is just a fermented drink containing some probiotic microorganisms and does not possess the same microbial population or chemical and physical characteristics of authentic kefir.  The aim of this project was to determine and compare the effects on the mouse immune system of kefir produced using natural kefir grain versus commercial kefir produced by starter culture.Methods:  Kefir produced with different cultures was fed to Balb/c mice (6-8 weeks, 20-25 grams, male) by gavage for two weeks at 300 μl/day. Intestinal tissues were collected from sacrificed mice at the end of the trial.  The control group of mice (CNI group) were fed with phosphate buffered saline (PBS).  The experimental treatments were mice fed mice fed authentic kefir produced using kefir grains (KGI group) and mice fed kefir produced using starter culture (STI group). Immunoglobulin (Ig) A, Immunoglubulin G, Interleukin (IL)-4, Interleukin-10, Interleukin-12, Toll Like Receptor (TLR)-4 were analyzed immunologically in intestinal fluid samples. Results: Results indicated that IgA values were 60.87, 72.78 and 55.31 ng/mL; IgG values were 26.59, 38.90 and 29.44 ng/mL; IL-4 values were 84, 40.28 and 53.28 pg/mL; IL-10 values were 110.98, 175.91 and 134.77 pg/mL; IL-12 values were 53.90, 22.93 and 24.75 pg/mL; TLR-4 values were 0.53, 0.43 and 1.37 ng/mL, for the CNI, KGI and STI groups, respectively.Conclusion: The high probiotic content of grain kefir had the ability to modulate many immunological mechanisms.Keywords: immune system, in vivo, kefir grain, probiotic, starter kefir culture


Author(s):  
Jorge Daniel Fonseca Blanco ◽  
Martha Del Pilar López Hernandez ◽  
Laura Sabrina Ortiz Galeano ◽  
Jenifer Criollo Nuñez ◽  
María Denis Lozano Tovar

Cocoa fermentation process is fundamental to generate flavors and aromas that are characteristics of chocolate. In Colombia, this process is carried out by microbiota that spontaneously colonizes cocoa beans, therefore the quality of the fermentation is inconsistent. Taking into account that the fermentation of cocoa beans is carried out by a consortium of microorganisms, the aim of thisresearch was to describe the effect of the addition of a specific mixture of yeasts, acetic acid bacteria, and lactic acid bacteria on the physicochemical and organolepticcharacteristics of cocoa beans (clone CCN 51). Isolates of two yeasts (Wickerhamomyces anomalus and Debaryomyces hansenii), three acetic acid bacteria (AAB), (Gluconobacter japonicus, Acetobacter tropicalis, and Acetobacter pasteurianus) and three lactic acid bacteria (LAB) (Pediococcus acidilactici, Lactobacillus brevis, and Lactobacillus plantarum) obtained fromprevious cocoa fermentations selected for their pectinases and acid production capacities in a specific mixture were used. Using the micro-fermentation technique, the effect of a biological starter was evaluated under different viable microorganismsratios (Yeasts: LAB: AAB as follows, 1: 1: 1, 1: 2: 2, 1: 2: 1, 1: 1: 2, 2: 1: 1, 2: 2: 1, 2: 1: 2, and 2: 2: 2). The concentration of each microorganism was standardized at 1x107 cfu/mL, then the biomass of 4 mL for ratio 1 and 8 mL for ratio 2 of each suspension of microorganisms was added at time zero. Different doses of inoculum were 0%, 1%, 2%, 3%, 4%, and 5% v/w mL inoculum/g cocoa beans. A beneficial effecton the sensory quality of cocoa beans was evidenced by the addition of microorganisms; the best proportion of microorganisms was 2:1:2 (yeasts:LAB:AAB) and the best inoculum dose was 3% (v/w) showing lower acidity, astringency, and bitterness, and emphasizing the cocoa flavors, fruity, nutty, and panela malt. 


2017 ◽  
Vol 866 ◽  
pp. 69-72
Author(s):  
Duongruitai Nicomrat ◽  
Siriphatrc Chamutpong

In the spontaneous vinegar fermentation process, diverse microorganisms considered as crucial microorganisms to succession of the vinegar fermentation control most pathogenic microorganisms. The predominant communities in fermented vinegar are acetic acid bacteria (AAB) functioning at the last step of acetic acid formation. However, lactic acid bacteria (LAB) also present in the vinegar, help produce high, quality vinegar and involve in the initial phase of starch degradation and alcohol production. In this study, the research was performed to understand the effects of LAB together with yeasts, Saccharomyces cerevisiae on on alcoholic and acetification production. In the experiment, mixtures of isolated LAB from fermented banana vinegar were tested for their functions together with yeasts in the alcoholic fermentation step. The results showed that indigenous LAB had more predominant effective species helping the induction of sugar but reduction in pH. This observation thus indicated the importance of inoculated LAB isolates in vinegar fermentation process as enhancer of the quality in vinegar fermentation.


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