Kombucha Culture Research Articles

Effect of freeze-dried kombucha culture on microbial composition and assessment of metabolic dynamics during fermentation

Kombucha is a traditional fermented beverage gaining popularity around the world. So far, few studies have investigated its microbiome using next-generation DNA sequencing, whereas the correlation between the microbial community and metabolites evolution along fermentation is still unclear. In this study, we explore this correlation in a traditionally produced kombucha by evaluating its microbial community and the main metabolites produced. We also investigated the effects of starter cultures processed in three different ways (control, starter culture without liquid suspension (CSC), and a freeze-dried starter culture (FDSC)) to evaluate changes in kombucha composition, such as antioxidant activity and sensory analysis. We identified seven genera of bacteria, including Komagataeibacter, Gluconacetobacter, Gluconobacter, Acetobacter, Liquorilactobacillus, Ligilactobacillus, and Zymomonas, and three genera of yeasts, Dekkera/Brettanomyces, Hanseniaspora, and Saccharomyces. Although there were no statistically significant differences in the acceptance test in sensory analysis, different starter cultures resulted in products showing different microbial and biochemical compositions. FDSC decreased Zymomonas and Acetobacter populations, allowing for Gluconobacter predominance, whereas in the control and CSC kombuchas the first two were the predominant genera. Results suggest that the freeze-drying cultures could be implemented to standardize the process and, despite it changes the microbial community, a lower alcohol content could be obtained.

Fermentation and characterisation of potential kombucha cultures on papaya-based substrates

The rising demands and increasing health-conscious population in global beverages consumptions promote the development of new variety of kombucha beverages using various plant and fruits. This study aimed to isolate, identify and characterise the microorganisms found in the kombucha starter. Isolated microorganisms showed high similarity (99%) towards an acetic acids bacterium, Komagataeibacter rhaeticus MFS1 and a yeast, Dekkera bruxellensis MFS1. Under low pH tolerance test, D. bruxellensis MFS1 was remained viable (log7 CFU/mL) but no viable cell was observed for K. rhaeticus MFS1 after 3 h exposure at pH 2. However, both strains retained viability when exposed to pH 3–4 for 3 h. When tested bile salt tolerance at different concentration (0.3–1%), D. bruxellensis MFS1 showed high tolerance with viability up to log7 CFU/mL after 4 h exposure at 1% concentration. In contrast, K. rhaeticus MFS1 only retained the viability up to 2 h under bile salt environment. The presence of 1.45–1.62% acetic acid with less than 0.5% ethanol was detected at the end of 4-days fermentation in both kombucha papaya samples. These preliminary results showed the potential of using these isolated strains as starter cultures for the production of novel functional fermented beverages from papaya pulp and leaves.

Kombucha beverage from non-conventional edible plant infusion and green tea: Characterization, toxicity, antioxidant activities and antimicrobial properties

Kombucha is a beverage based on a sugared medium fermented by a symbiotic culture of bacteria and yeast. The aim of this study was to produce unfermented and kombucha beverages with Malvaviscus arboreus and Camellia sinensis as substrates, and assess their physico-chemical characteristics, in vivo toxicities, antioxidant activities and antimicrobial properties . The beverages were prepared from infusions (0.5%, w/v), with sucrose (5.0%, w/v), kombucha culture (2.5%, w/v), and 1.0% (v/v) of the previously fermented beverage, and incubated at 24 ± 2 °C for 14 days. The results showed that both produced kombuchas are within the physico-chemical and microbiological parameters recommended by the Food and Drug Administration. None of the tested samples showed toxicity from the in vivo model of Galleria mellonella larvae. A significant increase of 145% w/v was observed on the total phenolic content of the Malvaviscus arboreus kombucha when compared to its infusion. Green tea and green tea kombucha showed antifungal activity against the pathogenic fungus Paracoccidioides brasiliensis . Green tea was also the only beverage to present antimicrobial activity against all fungi cultures evaluated and against Staphylococcus aureus and Listeria monocytogenes . Thus, it is possible that the type of substrate used in the kombucha production interferes with its bioactive properties . This report shows the potential use of non-conventional edible plant , such as Malvaviscus arboreus, as substrate for kombucha fermentation and for the first time the use of Galleria mellonella larvae as in vivo model of toxicity in the analysis of kombucha. • Fermented beverage produced using non-conventional edible plant - M. arboreus . • An increase in the phenolic content of the malvavisco infusion with fermentation. • In vivo toxicity assessment of tea infusions and kombuchas using G. mellonella . • Fungicidal activity of green tea infusion and kombucha against P. brasilienses.

Antioxidant and antibacterial activity of a beverage obtained by fermentation of yerba‐maté ( Ilex paraguariensis ) with symbiotic kombucha culture

This study aimed to characterize yerba-maté kombucha by showing its oxidative stress inhibitory property with Saccharomyces cerevisiae yeast as the model and to determine its antibacterial activity against Staphylococcus aureus and Escherichia coli. Different yerba-maté concentrations and fermentation temperatures were analyzed by an experimental design. Sucrose was used as the carbon source and green tea kombucha was used as the control. Yerba-maté beverage, which was fermented for 12 days had pH levels between 1.8 and 2.3; acidity from 4.8% to 6.0% acetic acid; total reducing sugars between 15.9 and 23.1 g/L; and total phenolic compounds (TPC) between 444.2 and 844.8 mg/L eq. gallic acid. Antioxidant activity, measured by the ABTS+ method, was from 16.1% to 31.3% higher than unfermented extracts. Yerba-maté kombucha exhibited antibacterial activity and was also effective to prevent the oxidative stress in S. cerevisiae. Practical applications Yerba-maté kombucha contains bioactive compounds that have potential applications in the food industry. Polyphenols are the main compounds found in yerba-maté kombucha, whose properties, such as antioxidant activity demonstrated in in vitro and in vivo tests, are potentially beneficial to health. Organic acids produced during fermentation to inhibit bacterial growth increase shelf life of the beverage and may be used to preserve other food. Thus, due to its significant potential, this study aimed to evaluate different yerba-maté concentrations and fermentation temperatures to obtain kombucha with high bioactive properties.

Use of kombucha culture in the production of fermented dairy beverages

Kombucha is a beverage obtained by fermenting tea containing sugar as a result of the symbiotic relationship between yeast and acetic acid bacteria. In this study, milk and various herbal teas (sage, blackberry, and green tea) were mixed in the ratio of 60:40 (v/v) and fermented with kombucha culture. 2.2-Diphenyl-1-picrilhydrazyl (DPPH) radical scavenging activity, total phenolic content, total reducing sugar content, and the microbiological and sensory properties of the fermented dairy beverage were examined. The highest DPPH radical scavenging activity was observed on the 1st day of storage of the blackberry tea-blended fermented beverage (98.48%), and the highest total phenolic content was observed on the 30th day of the green tea-blended fermented beverage (81.51 mg/mL). The maximum amount of glucuronic acid (0.42 g/100 mL) was observed on the 20th day of storage in the sage-blended fermented dairy beverage. The most favorite product was the blackberry blend, whereas the least favorite was the dairy beverage (control sample) fermented with kombucha based on sensory scores. This study demonstrates that milk and herbal teas could be successfully fermented with kombucha culture, thereby improving its functional properties.

Use of Response surface methodology to investigate the effect of several fermentation conditions on the antibacterial activity of several kombucha beverages.

This study aimed to investigate the effect of sugar concentration and fermentation time on the antibacterial activity of kombucha beverages prepared with four herbal teas. Four types of herbal teas including, black and green tea, lemon verbena, and peppermint were prepared then sweetened with 2, 5, and 8% sugar. The herbal teas inoculated with actively kombucha culture and after 7, 14, and 21days, the antibacterial activity of the supernatant of beverages was evaluated against four bacteria based on agar well diffusion method. RSM was used to investigate the effect of fermentation time, sugar concentration, and tea type on the antibacterial activity of beverages. Sugar concentration and fermentation time showed a significant effect on the antibacterial activity of beverages-against all tested bacteria and type of herbal tea affected the antibacterial activity of beverages-against E. coli and S. aureus. Kombucha prepared with black tea at sugar 8% and fermentation time of 21days showed the most antibacterial activity against B. cereus. The most antibacterial activity against S. aureus was observed in kombucha beverages prepared with green tea and peppermint for fermentation time of 21days, at 2% and 8% sugar, respectively. Prepared beverages with peppermint and lemon verbena at 8% sugar and 21days of fermentation showed the most antibacterial activity against E. coli and S. dysenteriae respectively. Generally, to achieve the highest antibacterial activity against the tested bacteria recommended preparation of kombucha beverages at the sugar of 8% and fermentation time of 21days.

Valorization of winery effluent using kombucha culture

Effluent from clarifying the must from wine production was used as a sole medium for kombucha fermentation. Usually, this effluent is disposed in the communal sewage system. This way of use and treating wastewater is certainly ecologically beneficial. The initial substrate for cultivation was prepared by diluting sterilized winery effluent to 70 g/L of total sugars, using boiled tap water. Kombucha starter was prepared using black tea and sucrose and added 10% (vol/vol) to the initial substrate. Fermentation was performed at 25°C. The obtained beverage was appropriate for consummation after 6 days. Obtained kombucha product had an enjoyable taste with wine alike note. The produced beverage had supreme DPPH radical scavenging ability and reducing power compared to traditional black- and green- tea based kombucha. Hydroxyl radical scavenging ability was also significant. A variety of organic acids was detected. Ascorbic acid content was 3.6 mg/L on the consumption day. Practical applications Using winery wastewater this way provides benefits for both winemakers and kombucha producers. Winemakers eliminate effluent with a lot of organic compounds for free and kombucha producers ensure raw material for the fermentation. An additional benefit is the eco-friendly disposal of wastewater that generally goes to communal sewerage.

Lachancea fermentati Strains Isolated From Kombucha: Fundamental Insights, and Practical Application in Low Alcohol Beer Brewing.

With a growing interest in non-alcoholic and low alcohol beer (NABLAB), researchers are looking into non-conventional yeasts to harness their special metabolic traits for their production. One of the investigated species is Lachancea fermentati, which possesses the uncommon ability to produce significant amounts of lactic acid during alcoholic fermentation, resulting in the accumulation of lactic acid while exhibiting reduced ethanol production. In this study, four Lachancea fermentati strains isolated from individual kombucha cultures were investigated. Whole genome sequencing was performed, and the strains were characterized for important brewing characteristics (e.g., sugar utilization) and sensitivities toward stress factors. A screening in wort extract was performed to elucidate strain-dependent differences, followed by fermentation optimization to enhance lactic acid production. Finally, a low alcohol beer was produced at 60 L pilot-scale. The genomes of the kombucha isolates were diverse and could be separated into two phylogenetic groups, which were related to their geographical origin. Compared to a Saccharomyces cerevisiae brewers’ yeast, the strains’ sensitivities to alcohol and acidic conditions were low, while their sensitivities toward osmotic stress were higher. In the screening, lactic acid production showed significant, strain-dependent differences. Fermentation optimization by means of response surface methodology (RSM) revealed an increased lactic acid production at a low pitching rate, high fermentation temperature, and high extract content. It was shown that a high initial glucose concentration led to the highest lactic acid production (max. 18.0 mM). The data indicated that simultaneous lactic acid production and ethanol production occurred as long as glucose was present. When glucose was depleted and/or lactic acid concentrations were high, the production shifted toward the ethanol pathway as the sole pathway. A low alcohol beer (<1.3% ABV) was produced at 60 L pilot-scale by means of stopped fermentation. The beer exhibited a balanced ratio of sweetness from residual sugars and acidity from the lactic acid produced (13.6 mM). However, due to the stopped fermentation, high levels of diacetyl were present, which could necessitate further process intervention to reduce concentrations to acceptable levels.

Hydrogel bacterial cellulose: a path to improved materials for new eco-friendly textiles

In this paper, we present a novel, ecologically friendly technology for the synthesis and modification of kombucha-derived bacterial cellulose in order to produce textiles of desired physicochemical and mechanical properties. The procedure of manufacturing cellulose in the form of a stable hydrogel bacterial cellulose (HGBC) ensures the desired properties for the application of such a material, e.g., in the textile industry. Bacterial cellulose was obtained from a yeast/bacteria kombucha culture (a symbiotic consortium also known as “tea fungus” or SCOBY) that is easy and cheap to breed. The process of bacterial cellulose manufacturing and modification was optimized in order to obtain a maximum recovery of raw materials, minimal energy consumption and ensure the use of only natural and renewable resources. The obtained materials were characterized in terms of their wettability, mechanical properties, and flame resistance. Moreover, the morphology and composition of the materials were determined by using scanning electron microscopy and infrared spectroscopy, respectively. Additionally, it was proven that the HGBC materials might be used to manufacture various articles of clothing using commonly available sewing techniques, which are not adequate for non-modified cellulose-based materials. Finally, the synthesized fabrics were used as wristbands and parts of T-shirts and tested on volunteers to determine a skin-to-skin contact behaviour of the prepared fabrics. The reported results allow for confirming that the HGBC fabric may be used as a new textile and the proposed synthesis method is in accordance with the “green chemistry.”Graphic abstract

Aflatoxin B1 degradation by microorganisms isolated from Kombucha culture

Aflatoxin B1 (AFB1) is the most harmful mycotoxin. Aflatoxin occurrence in tea makes this beverage unsuitable for consumption and presented risks to human health. Therefore, researches in aflatoxin microbial degradation are necessary to overcome this problem. Kombucha beverage is associated with health promoting effects. Thus, novel strains (Lactic acid bacteria and yeasts) were isolated from a Kombucha culture and assessed for AFB1 degradation in the liquid medium (Man Rogosa and Sharpe broth, yeast extract peptone dextrose broth and black tea). The main strains involved in AFB1 decontamination were identified based on DNA sequencing and the toxicity of the new products was evaluated on Hep2 cells and on Brine shrimp (Artemia salina). Our results showed that after 7 days of fermentation, kombucha was able to degrade 97% of AFB1 in black tea. Moreover, the effective yeasts present in Kombucha were identified as Pichia occidentalis, Candida sorboxylosa and Hanseniaspora opuntiae and the highest AFB1 degradation capacity was accorded to P. occidentalis (59%) when cultivated in black tea. Data on cytotoxicity tests on Hep2 cells and Brine shrimp (Artemia salina) showed that the biodegraded products were less toxic than pure AFB1. These findings suggest that, kombucha isolated strains could be potential candidates for application in the food and feed industry with a potential aflatoxin B1 detoxification properties.

Isolation and Screening of Microbial Isolates from Kombucha Culture for Bacterial Cellulose Production in Sugarcane Molasses Medium

Kombucha tea is a traditional fermented beverage of Manchurian origins which is made of sugar and tea. The fermentation involves the application of a symbiotic consortium of bacteria and yeast (SCOBY) in which their metabolites provide health benefits for the consumer and subsequently allow the product to protect itself from contamination. Additionally, kombucha tea fermentation also produces a byproduct in the form of a pellicle composed of cellulose (Bacterial Cellulose, BC). Compared to plant cellulose, BC properties are more superior, which makes it industrially important. However, BC production at industrial scale has been faced with many challenges, including low yield and high fermentation medium cost. Many researchers have focused their studies on the use of alternative low cost media, such as molasses, which is a by-product of sugar refining process. To maximize the BC production in molasses medium, it is important to select the microbial strains that can grow and produce BC at high yield in molasses. This study aimed to isolate and characterize BC-producing bacteria and a dominant yeast from kombucha culture which had been previously adapted in molasses medium. The isolation of bacteria was performed using Nutrient Agar (NA) and Hestrin and Schramm (HS) supplemented with cycloheximide, while yeast was isolated using Potato Dextrose Agar (PDA) supplemented with chloramphenicol. The most dominant colonies were isolated and then subjected to microscopic observation for morphological analysis. The pure bacteria and yeast isolates were then identified by sequencing the 16S rRNA gene and D1/D2 region of the 26S rRNA, respectively. The bacteria isolates obtained were all from closely related genera: Komagataeibacter sp. DS1MA.62A, Komagataeibacter xylinus, Komagataeibacter saccharivorans, Komagataeibacter xylinus and Gluconacetobacter saccharivorans. The single isolated yeast was identified as Brettanomyces bruxellensis. This study helps to elucidate the BC-producing species which thrive in molasses medium for potential use in the BC production using molasses as alternative cheap carbon source. Also, the study revealed that the co-culture of Komagataeibacter sp. DS1MA.62A and B. bruxellensis could produce BC from molasses supplemented with caffeine and acetate buffer at an average yield of 27.7±1.83 g/L.&#x0D; Keywords: Kombucha, SCOBY, bacterial cellulose, Acetobacter, Komagataeibacter, Brettanomyces, alternative medium, molasses, caffeine, acetate buffer.

Development of fermented vegetables in their ability to inhibit pancreatic lipase as antidyslipidemic agent

Improvement of public awareness of healthy living encourages the increase of demand for natural food products and provides health benefits for the body. Cardiovascular disease caused by atherosclerosis of blood vessel walls and thrombosis is the leading cause of death in the world. Dislipidemia and coagulation disorders are one of the most significant risk factors for the development of atherosclerotic conditions. The purpose of this study is to develop one of the healthy food products from fermented green vegetables (spinach, broccoli and katuk leaves) fermented by kombucha culture during fermentation as a functional beverage in its ability inhibits pancreatic lipase as anti-dyslipidemia. Results showed a correlation between the ability to defend against free radicals and the ability to inhibit pancreatic lipase enzyme activity. The optimum conditions obtained in the fermentation of katuk leaf vegetables based on the ability to inhibit pancreatic lipase activity (% inhibition) and the ability to inhibit free radicals (DPPH), which is for 6 days fermentation of 91.44%, and 88.62%, with a pH value 3.98.

Optimization of robusta green coffee fermentation using response surface methodology

Kombucha coffee is a fermented coffee bean, which is extracted using a combination of bacteria and yeast. Kombucha coffee can be obtained by optimizing the three variables, namely sugar concentration, incubation temperature and duration of fermentation using a response surface methodology (RSM). This study aimed to optimize the three variables that influence the fermentation of Robusta green coffee beans using a kombucha culture to obtain low caffeine content and high levels of chlorogenic acid. RSM calculation was used high-performance liquid chromatography (HPLC) on caffeine and chlorogenic acid that content in kombucha coffee. The results of modeling used a central composite experimental design (CCD). The results of the optimization study showed that the lowest concentration of caffeine and chlorogenic acid was obtained at sugar concentration of 6.77% (b/v), incubation temperature of 25°C and incubation for 18 days. Finally, the fermentation using RSM on kombucha coffee required an additional variable which is the amount of kombucha culture inoculums, as well as the variables of sugar concentration, incubation temperature and duration of fermentation. Key words: Kombucha coffee; caffeine; chlorogenic acid.

In vitro procena biološke dostupnosti antioksidativne aktivnosti kombuha napitaka nakon gastro i intestinalne digestije

Kombucha beverage is a fermented product obtained by kombucha culture fermentation of, usually, black or green tea. Besides black and green tea, kombucha also ferments water extracts of medicinal herbs. The obtained products possess antioxidant activity. The aim of this paper was to establish the antioxidant potential of kombucha beverages with black tea, green tea, and medicinal herbs after pepsin and pancreatin in vitro digestion. The radical scavenging ability of DPPH and hydroxyl radical, as well as reducing power of kombucha products was determined. At the end of the digestion process, the highest antioxidant potential towards hydroxyl radical showed only kombucha beverages with peppermint and stinging nettle extract. Results for reducing power and antioxidant capacity to scavenging DPPH radical showed a decrease in values after the digestion process.

Evaluation of fungicidal properties of post-cultured liquid medium from the culture of Kombucha microorganisms against selected mold fungi

Evaluation of fungicidal properties of post-cultured liqiud medium from the culture of Kombucha microorganisms against selected mold fungi. The paper presents the results of the evaluation of fungicidal activity of post-cultured liquid medium from Kombucha microrganism on molds Alternaria alternata and Trichoderma viride. The obtained results confirmed that the medium on which Kombucha microorganisms grew, have fungicidal activity against mold fungi. The lowest concentration of post-cultured liqiud medium, inhibiting the growth of A. alternata and T. viride, on the 4th day of culture, was respectively: 5% and 15%. The total absence of fungal growth was observed on medium containing 20% medium from Kombucha culture

Kombucha scoby-based carbon as a green scaffold for high-capacity cathode in lithium–sulfur batteries

A ternary composite cathode of sulfur, poly(acrylonitrile) (PAN), and carbon was investigated for the possible use in Li–S batteries. The carbon used in this work was obtained from kombucha tea or tea fungus with potassium hydroxide activation process. The flaky structure of functionalized carbon derived from a waste part of kombucha culture has micropores and mesopores with a large pore volume, which are favorable for impregnating elemental sulfur. The ration of the ternary composite was based on a simple process involving a dispersion of the carbon with that of S/PAN, followed by a simple heat treatment. The cathode delivered an initial discharge capacity of 1666 mAh g−1 at C/10 rate and a 100th cycle capacity of 838 mAh g−1. This study exploits the cumulative contribution of a conductive carbon and PAN in the improved performance of the cathode.

Optical metamaterials for decontamination of translucent liquids and gases

Metamaterials with periodical structures like quartz or glass small granules irradiated by UV-C to act against microbial contamination of translucent liquids and gases are studied. Investigations of the modifications of individual metamaterial elements when UV evanescent waves are dispersed in the optical contact zone, as a function of granule geometry, were performed. Different situations were investigated, when quartz (SiO2), glass, or black (plastic) materials with dimensions of about 0.5–3 mm are separately placed into a quartz tube of about 2.7 cm diameter and 90 cm length, named ‘core tube’. Quartz granules transmit within the 240–400 nm region of the Hg lamp and ensure an effective decontamination of translucent liquids and gases. Our approach is based upon the increased transfer of UV radiation via evanescent waves in case of unordered metamaterials present in contaminated fluids. We made a series of estimations of the decontamination rate of this type of metamaterials versus ordered metamaterials consisting of spherical elements. Experiments have convincingly demonstrated that both quartz and glass metamaterials can effectively annihilate Coliform (including Escherichia coli) or Enterococcus bacteria, as well as yeast and Kombucha cultures. The decontamination efficiency was assessed both in dynamic and static treatment regimes. Control experiments were performed in the absence of metamaterials and/or UV-C irradiation.

Recovery of Fermented Spinach (&lt;i&gt;Amaranthus&lt;/i&gt; sp.) Concentrate Through Ultrafiltration Membrane Process as Source of Folic Acid for Smart Food Formula

Fermentation process on spinach (Amaranthus sp.) by Kombucha culture was done as an effort to recover naturally folic acid as bioactive components to increase smartness. The experimental activity was done by means of UF membrane (100,000 MWCO) fitted in Stirred Ultrafiltration Cell (SUFC) at stirrer rotation speed 200 and 400 rpm, room temperature, pressure 20 and 40 Psi for 30 min. Result of experimental activity showed that based on both selectivity and recovery of folic acid, process optimization of UF was reached at stirrer rotation speed 200 rpm and pressure 40 Psi. In the optimum condition, SUFC technique was able to recover folic acid in retentate 67.75% and in permeate 97.27% (63.19 µg/mL). Identification of monomer in permeate from the optimum process treatment was find out folic acid monomer with molecular weight (MW) 441.39 and relative intensity 93% at mass spectra T2.32 between m/z 257–304 and glutamic acids monomer with MW 148.57 and relative intensity 0.22% at mass spectra T2.82 between m/z 415–470. Other dominant monomer were folic acid fraction.

Purification and Components Identification on Spinach (Amaranthus sp. L.) and Broccoli (Brassica oleracea L.) Fermented by Kombucha Culture as Source of Folic Acid Through Stirred Microfiltration Cell (SMFC)

Purifying spinach (Amaranthus sp.) and broccoli ( Brassica oleracea L.) fermented by Kombucha culture through microfiltration (MF) membrane of 0.15 µm fitted in Stirred Microfiltration Cell (SMFC) produced subsequently both fermented spinach and broccoli concentrates with compositions of folic acid of 58.9 µg/mL and 28.1 µg/mL, total solids of 6.29 % and 5.76 %, total acids of 0.57 % and 0.93 %, polyphenol of 0.25 % and 0.06 %, and reducing sugars of 105.34 mg/mL and 66.09 mg/mL. In these conditions, recovery of both fermented spinach and broccoli concentrates mentioned above were 1.07 times and 0.64 times, 0.95 times and 0.97 times, 1 times and 1 times, 3.57 times and 0.85 times, 1.22 times and 0.68 times compared to feed, Based on both the best molecular weight (MW) and relative intensity, dominant monomer was reached for fermented spinach extract and gave folic acid fractionation, folic acid and polyphenol with MW of 219.57 Dalton (Da.), 442.99 Da. and 192.11 Da., and relative intensities of 19.78 %, 0.81 % and 1.65 %, respectively.

Fermentation of Spinach (Amaranthus spp) and Broccoli (Brassica oleracea L.) Using Kombucha Culture as Natural Source of Folic Acid for Functional Food

The importance of folate (folic acid, B9 vitamin, pteroyl-L-glutamic acid) in human diet for the prevention of neural tube defects during pregnancy is widely known. Green vegetables are known to be a potential source of natural occurring folic acid instead of legumes and grains. The fermentation process using a mixed culture of kombucha is an alternative of natural folic acid production from green vegetables. Broccoli and spinach was selected based on its folic acid content compared to other vegetables. This research was conducted by the extraction of broccoli and spinach at 80 °C with a ratio of vegetable and water of 1:4. The inoculum was obtained by inoculating kombucha culture on vegetable extracts for 7 days at room temperature. The vegetable extracts were then fermented using inoculum with concentration of 15, 25 and 35% (v/w of polyphenol of vegetable extracts) for 0, 3, 6, 9, 12 and 15 days at room temperature. The analysis were performed on total solids, polyphenol, dissolved protein, reducing sugars, amylase and protease activities, total acid, total plate counts and folic acid contents. This study showed that the type of vegetables, inoculum concentration and fermentation time affect the chemical composition of fermented vegetables. Fermented broccoli and spinach with inoculum concentration of 15% had the highest yield of folic acid of 69,52 µg/mL and 62,05 µg/mL after 6 days and 3 days of fermentation time, respectively. Identification of folic acid in fermented vegetable extracts at optimum condition by LC-MS were carried out with the relative intensity for fermented spinach and broccoli were 0,48% and 0,56%, respectively, with a molecular weight of 459 m/z are identified as 5-methyl tetrahydrofolate.