Article

Changes in content of organic acids and tea polyphenols during kombucha tea fermentation

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Abstract

Kombucha tea is a fermented tea beverage produced by fermenting sugared black tea with tea fungus (kombucha). Tea polyphenols which includes (-)-epicatechin (EC), (-)-epicatechin gallate (ECG), (-)-epigallocatechin (EGC), (-)-epigallocatechin gallate (EGCG) and theaflavin (TF) have been reported to possess various biological activities. The present study focused on changes in content of organic acid and tea polyphenols in kombucha tea prepared from green tea (GTK), black tea (BTK) and tea manufacture waste (TWK) during fermentation. Concentration of acetic acid has reached maximum up to 9.5 g/l in GTK on 15th day and glucuronic acid concentration was reached maximum upto 2.3 g/l in BTK on 12th day of fermentation. Very less concentration of lactic acid was observed during the fermentation period and citric acid was detected only on 3rd day of fermentation in GTK and BTK but not in TWK. When compared to BTK and TWK very less degradation of EGCG (18%) and ECG (23%) was observed in GTK. TF and thearubigen (TR) were relatively stable when compared to epicatechin isomers. The biodegradation of tea catechins, TF and TR during kombucha fermentation might be due to some unknown enzymes excreted by yeasts and bacteria in kombucha culture.

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... It is know that some strains, in particular lactic acid bacteria, are able to degrade phenolic compounds. Jayabalan et al. (2007) noted epicatechin degradation to vanillic acid during black tea fermentation [98]. In the study of Vázquez-Cabral et al. (2014) lower contents of catechin, epicatechin, hydroxybenzoic acid derivatives (ellagic) hydroxycinnamic (chlorogenic acid) and higher concentrations of vanillic, benzoic, protocatechuic, gallic acid as well as caffeic acids were noted for functional beverage obtained from infusions of oak leaves [36]. ...
... It is know that some strains, in particular lactic acid bacteria, are able to degrade phenolic compounds. Jayabalan et al. (2007) noted epicatechin degradation to vanillic acid during black tea fermentation [98]. In the study of Vázquez-Cabral et al. (2014) lower contents of catechin, epicatechin, hydroxybenzoic acid derivatives (ellagic) hydroxycinnamic (chlorogenic acid) and higher concentrations of vanillic, benzoic, protocatechuic, gallic acid as well as caffeic acids were noted for functional beverage obtained from infusions of oak leaves [36]. ...
... What is more, glucuronization also plays a significant role in hormone deficiencies and/or excesses of steroid hormones: increased solubility of steroids in water improves their bioavailability at low concentrations in the body, whereas in the case of high levels of steroid hormones, binding allows for excretion [8]. [57,98,109]. ...
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Kombucha is a low alcoholic beverage with high content of bioactive compounds derived from plant material (tea, juices, herb extracts) and metabolic activity of microorganisms (acetic acid bacteria, lactic acid bacteria and yeasts). Currently, it attracts an increasing number of consumers due to its health-promoting properties. This review focuses on aspects significantly affecting the bioactive compound content and biological activities of Kombucha tea. The literature review shows that the drink is characterized by a high content of bioactive compounds, strong antioxidant, and antimicrobial properties. Factors that substantially affect these activities are the tea type and its brewing parameters, the composition of the SCOBY, as well as the fermentation parameters. On the other hand, Kombucha fermentation is characterized by many unknowns, which result, inter alia, from different methods of tea extraction, diverse, often undefined compositions of microorganisms used in the fermentation, as well as the lack of clearly defined effects of microorganisms on bioactive compounds contained in tea, and therefore the health-promoting properties of the final product. The article indicates the shortcomings in the current research in the field of Kombucha, as well as future perspectives on improving the health-promoting activities of this fermented drink.
... The health beneficial impacts of kombucha has reported for treatment of several diseases including diabetes, the risk of heart disease (by reducing cholesterol and blood pressure), liver detoxification (by binding glucuronic acid to toxins), losing weight, relieving arthritis and stimulating the immune system, as well as preventing cancer (Dufresne & Farnworth, 2000;Srihari & Satyanarayana, 2012;Malbasa et al., 2014;Gamboa-Gómez et al., 2016, Jayabalan et al., 2007. Also acetic acid content of kombucha resulted in antimicrobial inhibitory impact (against Bacillus cereus, Helicobacter pylori, Shigella sonei, Staphylococcus aureus, Escherichia coli, Salmonella interatidicus) and antifungal properties of kombucha (Battikh et al., 2013;Reiss, 1994). ...
... Fermentation of kombucha leads to release of polyphenols, e.g. catechins, with high antioxidant properties (Srihari & Satyanarayana, 2012;Jayabalan et al., 2007). Also, kombucha is rich in antioxidants such as vitamins C and E, beta-carotene and other carotenoids Gamboa-Gómez et al., 2016). ...
... The total phenol content and antioxidant activity of the kombucha before and after drying was measured by Folin-Ciocalteau method (Singleton et al., 1999), and radical 1,1-diphenyl 2-picrylhydrazyl absorption and cupric ion reducing antioxidant capacity methods (Jayabalan et al., 2007;Yikmis & Tuggum, 2019), respectively. ...
Article
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Abstract Kombucha can be produced by coculture of a consortium of bacteria and fungi in a sweetened black tea. Determining the type of microbial population as well as their survival is important because they lead to beneficial and sensory properties of the product. In this study, microorganisms were isolated from kombucha and identified using culture and molecular methods and vacuum dried. Also total phenol content, and antioxidant properties of beverage were characterized. Microorganism viability and sensory evaluation was conducted by flow cytometery and a 5-point hedonic test before and after drying. 8-isolated species were recorded in NCBI. Lactobacillus and Kumagataeibacter and Weissella spp. were the bacterial species, while Starmella bacillaris and Hanseniaspora uvarum were the 2-yeast species identified in kombucha beverage. Microbial count increased from 3.59% on the start day to 96.6% on day 14. The results of sensory evaluation show that, in general, the produced kombucha drink was accepted by the evaluators. The highest score for overall acceptance on day 14 was equal to 4.6. Starmella bacillaris and Hanseniaspora uvarum were first isolated from kombucha with enhanced antioxidant properties. These strains, together with yeast are recommended for use in beverage fermentation processes to production of bioactive compounds.
... Kombucha has two phases: a liquid part and a floating cellulose pellicle. The main acids present in the kombucha are acetic, gluconic, tartaric, malic and oxalic (Jayabalan et al., 2007;Laureys et al., 2020;Malbaša et al., 2011). Kombucha beverage was claimed to have many beneficial effects on human health. ...
... Substrate originated from a grape which explains strong buffering properties. Black tea kombucha typically has a much higher pH value at the beginning of the fermentation, between 5 and 5.5, while after the ninth day of the fermentation, winery effluent kombucha is comparable with black tea and Pu-erh the kombucha (Jayabalan et al., 2007;Kallel et al., 2012;Zhao et al., 2018). Since the original pH was low, it could not be used as a parameter for the end of the fermentation, only to confirm that fermentation occurred by a slight decrease. ...
... The highest value was measured after 9 days at 30 • C with 7% (35.65 g/L), while the lowest was measured at the beginning of the fermentation with 5% of sugar at 25 • C (2.13 g/L). The initial substrate had lower total acidity (5.39 g/L) than all fermented samples, confirming that kombucha produces a significant amount of various acids (Dufresne & Farnworth, 2000;Jayabalan et al., 2007). After nine days of fermentation, for all three temperatures, a sugar content gradient can be observed. ...
Article
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Kombucha beverage was produced using effluent from clarifying the grape must. Substrate for fermentation was prepared by diluting sterilized winery effluent to 70, 50, and 30 g/L of total sugars. Fermentation lasted for nine days at 20, 25, and 30 °C. A pleasant taste kombucha was produced. The beverage was ready to drink after three days of fermentation. From 300 mL fermentation volume, more than 40 g/L of biomass was produced at maximum temperature and sugar content. Acetic acid was the acid, with a peak concentration of 14.63 g/L after nine days at 30 °C and 70 g/L. Tartaric acid originated from the grape. Oxalic acid content was higher at the lower fermentation temperature. Produced kombucha had good antimicrobial properties. Higher temperature and sugar content promote antimicrobial activity against both Gram-positive and Gram-negative bacteria. No activity against yeast was observed. Antimicrobial properties against bacteria and acetic, tartaric, and oxalic acids content were modelled using RSM. Correlation analysis showed a positive relationship between acetic and tartaric acid content and antimicrobial activity.
... Citric acid is namely involved in the TCA cycle, whereas gluconic acid is a biomarker for the oxidative metabolism of acetic acid bacteria and highlights their activity during P1, the acidification phase of kombucha production [9,19]. Finally, increase of gallic acid during kombucha production has been reported in other studies [20][21][22]. Along with the increase in epigallocatechin, this suggests the release of gallic acid through hydrolysis of gallate groups attached to polyphenols via ester bonds (for example epigallocatechin gallate). ...
... Such compounds' masses might be higher than the range of analysis, or else they did not belong in the databases. It has been hypothesized that polyphenol transformation was induced by microbial activity, either spontaneously due to physical chemical changes, such as the decrease in pH value, or biologically through microbial enzymatic activity, that has yet to be determined [21,27]. Indeed, the pH value of D7 samples were 4.2 ± 0.1, which is higher than the values (between 3.2 and 3.5) reported in other studies that described such phenomenon [13,21]. ...
... It has been hypothesized that polyphenol transformation was induced by microbial activity, either spontaneously due to physical chemical changes, such as the decrease in pH value, or biologically through microbial enzymatic activity, that has yet to be determined [21,27]. Indeed, the pH value of D7 samples were 4.2 ± 0.1, which is higher than the values (between 3.2 and 3.5) reported in other studies that described such phenomenon [13,21]. However, different production parameters explain such differences and all values are included in the range of commercial products (pH values above 3) [10]. ...
Article
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Kombucha is a traditional fermented beverage obtained from the transformation of sugared black tea by a community of yeasts and bacteria. Kombucha production recently became industrialized, but its quality standards remain poorly defined. Metabolomic analyses were applied using FT-ICR-MS to characterize the impacts of production phases and the type of tea on the non-volatile chemical composition of kombucha. Independently from tea type, the first phase of acidification in open vessel was characterized by the release of gluconate and gallate from acetic acid bacteria metabolism and probably from polymeric polyphenols, respectively. The second phase of carbonation in closed vessel induced a consumption or transformation of oleic acid that could be consecutive of oxygen limitation. The first phase had the most impact on molecular diversity, but tea type mainly influenced the global composition in polyphenol profile. Black tea polyphenols were more impacted by microbial activity compared to green tea polyphenols.
... The particles that are in suspension can be made up of microorganisms or large molecules ranging in size from 1 to 1000 nm ( Petrucci, 2011 ). Although there has not been much research into the colloids in kombucha, researchers suggested that the colloids are a mixture of aggregated proteins ( Jayabalan et al., 2007 ), polyphenols, and cellulose fibers produced by acetic acid bacteria ( Goh et al., 2012a ;Zhang et al.,2018 ). ...
... However, it should be noted that the organic acid contributions by yeast and lactic acid bacteria should not be ignored either. Along with acetic acid, glucuronic and gluconic are the major organic acids, while lactic, succinic, and malic acid are the minor organic acids found in kombucha ( Blanc, 1996 ;Chakravorty et al., 2016 ;De Filippis et al., 2018 ;Jayabalan et al., 2007 ;Malba š a et al., 2002 ). Organic acids are often described as being tart or sour when found in a beverage. ...
... Few researchers have focused on what happens to polyphenols following the fermentation process Jayabalen et al. (2007) . reported seeing a decrease in epicatechin, epigallocatechin, and gallate derivatives within the first nine days of the fermentation process and then an increase in nongallate species until day twelve ( Jayabalan et al., 2007 ). ...
Article
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Fermentation is one of the oldest preservation techniques used by mankind with known actions of fermentation dating back to several millennia before the common era. From this came the fermentation of tea beverages which we commonly call kombucha. The origins of fermented teas, and ultimately the concept of kombucha, has a multitude of backstories and derivations stemming back several thousand years. Kombucha is made by fermenting sweetened black or green tea using a mixed fermenting culture of yeast and acetic acid bacteria. This review gives a holistic overview of the fermented tea beverage known as kombucha including an overview of the history of kombucha, an overview of the brewing and manufacturing of the beverage including different brewing techniques and ingredients, discussion of the biochemical and microbiological aspects of the fermentation process, the flavor and chemical profile of kombucha, as well as the impacts of kombucha on human health.
... Notable phenolic compounds present in kombucha include phenolic acids, theaflavins (TFs), thearubigins (TRs), and catechins (Cardoso et al., 2020). Black tea kombucha also contains organic acids such as acetic acid, lactic acid, gluconic acid, glucuronic acid, tartaric acid, malic acid, and, to a lesser extent, citric acid (Jakubczyk, Kałduńska, Kochman, & Janda, 2020;Jayabalan, Marimuthu, & Swaminathan, 2007). ...
... and Zygotorulaspora spp.) (Morales, 2020). In addition to their role in producing ethanol, CO 2 , organic acids, and cellulose, the activity of these microorganisms is associated with changes in the phenolic composition of the kombucha (Cardoso et al., 2020;Jakubczyk, Kałduńska, Kochman, & Janda, 2020;Jayabalan, Marimuthu, & Swaminathan, 2007;Kallel, Desseaux, Hamdi, Stocker, & Ajandouz, 2012). The concentration of total phenolics in kombuchas increases with fermentation due to the catabolic and anabolic reactions carried out by the microorganisms (Chen & Sang, 2014;Jakubczyk, Kałduńska, Kochman, & Janda, 2020;Jayabalan, Marimuthu, & Swaminathan, 2007), resulting in higher antioxidant capacity relative to tea (Chu & Chen, 2006). ...
... In addition to their role in producing ethanol, CO 2 , organic acids, and cellulose, the activity of these microorganisms is associated with changes in the phenolic composition of the kombucha (Cardoso et al., 2020;Jakubczyk, Kałduńska, Kochman, & Janda, 2020;Jayabalan, Marimuthu, & Swaminathan, 2007;Kallel, Desseaux, Hamdi, Stocker, & Ajandouz, 2012). The concentration of total phenolics in kombuchas increases with fermentation due to the catabolic and anabolic reactions carried out by the microorganisms (Chen & Sang, 2014;Jakubczyk, Kałduńska, Kochman, & Janda, 2020;Jayabalan, Marimuthu, & Swaminathan, 2007), resulting in higher antioxidant capacity relative to tea (Chu & Chen, 2006). However, no studies to date have precisely detailed the possible changes in the phenolic profile of kombuchas during fermentation. ...
Article
This study shows the changes in physicochemical and microbiological composition, and in the phenolic profile of black tea kombucha during fermentation. In addition, the antimalarial potential of the kombucha was evaluated. Ultra-performance liquid chromatography-mass spectrometry multiplex analysis (UPLC-MSE) results revealed a 1.7 log2 fold-change increase in phenolics with the fermentation time, with emphasis on the increase of phenolic acids (0.3 log2 fold-change). Over time there was degradation of flavonoids such as nepetin, hesperidin and catechin 5-O-gallate, to the detriment of the increase in phenolic acids such as gallic acid and cinnamic acid. In addition, black tea kombucha presented antiplasmodic activity against the 3D7 (sensitive chloroquine) and W2 (resistant to chloroquine) strains. Therefore, important changes in the black tea kombucha phenolic profile take place during fermentation, which may help in the development of kombuchas with higher bioactive potential and contribute to a better understanding of the kombucha fermentation process.
... Kombucha is the result of the fermentation of sweetened green or black tea (Camellia sinensis) by the action of a Symbiotic Culture of Bacteria and Yeasts called SCOBY, resulting in a refreshing, bittersweet, and slightly carbonated drink Jayabalan et al., 2007Jayabalan et al., , 2014. These microorganisms are responsible for interactions during a symbiotic process generating metabolites such as acids (acetic, gluconic, glucuronic, citric, among others), water-soluble vitamins (B1, B2, B6, B12, and C), ethanol, carbon dioxide, and cellulose (Bauer-Petrovska & Petrushevska-Tozi, 2000; Gaggìa et al., 2019;Jayabalan et al., 2007;Leonarski, Cesca, Borges, et al., 2021;Malbaša et al., 2011;Marsh et al., 2014;Neffe-Skocińska et al., 2017). ...
... Kombucha is the result of the fermentation of sweetened green or black tea (Camellia sinensis) by the action of a Symbiotic Culture of Bacteria and Yeasts called SCOBY, resulting in a refreshing, bittersweet, and slightly carbonated drink Jayabalan et al., 2007Jayabalan et al., , 2014. These microorganisms are responsible for interactions during a symbiotic process generating metabolites such as acids (acetic, gluconic, glucuronic, citric, among others), water-soluble vitamins (B1, B2, B6, B12, and C), ethanol, carbon dioxide, and cellulose (Bauer-Petrovska & Petrushevska-Tozi, 2000; Gaggìa et al., 2019;Jayabalan et al., 2007;Leonarski, Cesca, Borges, et al., 2021;Malbaša et al., 2011;Marsh et al., 2014;Neffe-Skocińska et al., 2017). ...
... During the traditional kombucha fermentation, several studies reported an increase in the concentration of phenolic compounds ( Table 4). The exact mechanisms of this increase are still undetermined, but several studies report the degradation of polyphenols into smaller molecules due to the activity of enzymes produced by the microbial consortium, which also increases antioxidant activity (Jakubczyk et al., 2020;Jayabalan et al., 2007Jayabalan et al., , 2008. More recently, Jafari et al. (2020) observed a synergistic effect between invertase activity and kombucha antioxidant activation. ...
Article
Kombucha is a beverage obtained by fermenting sweetened green or black tea with a symbiotic culture of bacteria and yeasts (SCOBY), which claims nutritional characteristics. As demand for kombucha increased, alternative extracts to green or black tea such as herbs, fruits, milk, agro-industrial materials started to be used in fermentation, giving rise to kombucha-like beverages. The literature review shows that the procedure and conditions used to obtain kombucha-like beverages are similar to the traditional fermentation. However, some additional steps may be necessary to prepare the raw material for its use as an alternative to green or black tea, the main approaches being highlighted in this review. Bioactive compounds (mainly phenolics) are considered one of the main attractions of kombucha due to their antioxidant characteristics. It is observed that, regardless of the extract used, the bioactive compounds (mainly phenolics) and also the antioxidant activity tend to increase during the fermentation of these beverages. Thus, the use of alternative raw materials to tea for the preparation of kombucha is viable and tends to serve a wide range of products according to different regions of the world. These new beverages have similar characteristics to the traditional beverage and respect the diversity of consumer market trends.
... Kombucha is a tea beverage, which is fermented with a symbiotic culture of bacteria and yeast (SCOBY) [1][2][3]. The word 'healthy' has been often used to describe kombucha in the literature [2][3][4]. ...
... Kombucha is a tea beverage, which is fermented with a symbiotic culture of bacteria and yeast (SCOBY) [1][2][3]. The word 'healthy' has been often used to describe kombucha in the literature [2][3][4]. In the late 2010s, kombucha captured the consumers' attention as a healthy alternative to soft drinks in the U.S. [5]. ...
Article
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Consumers’ demand for ‘healthy’ food is growing at a fast pace. Beverages are one of the fastest-growing segments in the healthy food market. Kombucha is a product with a rapid market growth and is considered a ‘healthy beverage’. Kombucha drinkers (n = 296) in the contiguous United States (U.S.) were targeted to investigate differences in the various consumer segments regarding the healthy eater’s behavior, namely—(1) healthy diet stage-of-change attitudes, (2) healthy eating criteria, and (3) label information usage. An online survey questionnaire was used as a data collection tool. The data were analyzed via chi-square tests and multiple correspondence analysis (MCA). The majority of kombucha consumers were health-conscious and kombucha fitted into their view of a healthy diet. The female, older, western U.S. residents, and higher-educated consumers were more likely to take action and maintain a healthier diet. Healthy eaters’ idea of a healthy diet was very similar to that of the general population. Kombucha consumers focused mainly on sugar/calories and natural/organic ingredients. Additional investigations to expand the understanding of the healthy eater’s behavior with actual kombucha samples are needed in the future.
... Products H1 and M2 had the highest concentration of citric acid-0.36 and 0.34 g/L, and C1 had the lowest at 0.07 g/L. Malbaša et al., 2011 measured the citric acid concentration accounted for 2.5% of the total acidity, and Jayabalan et al., 2007 citric acid concentrations varied between 0.03 and 0.11 g/L. Our results showed this acid content in studied kombucha was insignificant, what was confirmed by the literature. ...
... Our results showed that the amount of these acids was insignificant. Controversially, these concentrations vary in the literature from 2.3 g/L (Jayabalan et al., 2007) to 7.36 g/L (Chakravorty et al., 2016). Moreover, the metabolic pathways of gluconic and glucuronic acids showed that these acids could be metabolised to other chemical components, such as ascorbate, amino sugars, cofactors, and inositol ("KEGG COM-POUND C00191," n.d.). ...
Article
The kombucha market is a fast-growing segment in the functional beverage category. The selection of kombuchas on the market varies between the traditional and flavoured kombuchas. Our research aimed to characterise the chemical, microbial, and sensory profiles of the commercial kombuchas. We analysed 16 kombuchas from 6 producers. The dominant metabolites were acetate, lactate, and ethanol, the last of which might put some kombuchas into the alcoholic beverage section in some countries. The metagenomic analyses demonstrated that LAB dominates in green tea, and AAB in black tea kombuchas. The main bacterial species were Komagataeibacter rhaeticus and Lactobacillus ssp, and yeast species Dekkera anomala and Dekkera bruxellensis. The sweet and sour balance correlated with acid concentrations. The free sorting task showed that commercial kombuchas clustered into three main categories “fruity and artificial flavour”, herbal and tea notes”, and “classical notes”. Our research results showed the necessity of the definition of kombucha.
... In addition, SCOBY performs well in different media such as fruit juices, corn liquor, and media containing polyphenols at relatively low costs. It is used as a starter culture, together with black or green tea, to prepare Kombucha tea (KT) [60,61]. Green tea mainly provides four polyphenolic derivatives: (-)-epicatechin (EC), (-)-epicatechin-3-gallate (ECG), (-)-epigallocatechin (EGC) and (-)-epigallocatechin-3-gallate (EGCG). ...
... Green tea mainly provides four polyphenolic derivatives: (-)-epicatechin (EC), (-)-epicatechin-3-gallate (ECG), (-)-epigallocatechin (EGC) and (-)-epigallocatechin-3-gallate (EGCG). Likewise, black tea mainly provides two polyphenolic derivatives: theaflavin and thearubigins [61]. In addition, they are used as a source of nitrogen for fermentation [62]. ...
Article
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Bananas are one of the most important crops worldwide. However, a large amount of residual lignocellulosic biomass is generated during its production and is currently undervalued. These residues have the potential to be used as feedstock in bio-based processes with a biorefinery approach. This work is based on the valorization of banana leaf and has the following objectives (i) to determine the effect of certain physical and environmental factors on the concentration of glucose present in banana leaf extract (BLE), using a statistical regression model; (ii) to obtain Bacterial Nanocellulose (BNC), using BLE (70% v/v) and kombucha tea as fermentation medium. In addition, the physicochemical properties of BNC were evaluated by X-ray diffraction (XRD), Fourier transform infrared (FTIR), and thermogravimetric analysis (TGA). The results indicate that storage time, location, leaf color, and petiole type are factors related to BLE concentration, which is reduced by approximately 28.82% and 64.32% during storage times of five days. Regarding BNC biosynthesis, the results indicate that the highest yield, 0.031 g/g, was obtained at 21 days. Furthermore, it was determined that the highest production rate was 0.11 gL−1h−1 at 11 days of fermentation. By FTIR, it was determined that the purification step with NaOH (3M) should be carried out for approximately two hours. This research supports the development of a circular bioeconomy around the banana value chain, as it presents a way of bioprocessing residual biomass that can be used to produce bioproducts.
... However, they had a statistically significant difference (p < 0.05) between treatments and over time. This behavior is probably due to the extracellular proteins secreted by bacteria during the fermentation time [73]. Furthermore, the increase in the total content of betalains has a positive correlation regarding the total concentration of proteins, due to the fact that they are nitrogenous compounds [74]. ...
... These correlations could be to compounds with high AA that were formed or released during storage, thanks to the adsorption of water [60], and it can be observed despite the presence of betalains [64]. Storage with high water activity facilitates hydrolysis, causing phenolic compounds to react with oxygen and produce an enriched medium that has strong radical elimination and reduction properties [65,73]. ABTS˙and DPPH˙= Antioxidant activity, TP = Total polyphenols, TB = Total betalains, BC = Betacyanins, BX = Betaxanthins, TPC = Total protein concentration, L* = Luminosity, a* (tendency to red), b* (tendency to green), and SYN = Syneresis. ...
Article
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Beet has been used as an ingredient for functional foods due to its high antioxidant activity, thanks to the betalains it contains. The effects of the addition of beet extract (liquid and lyophilized) on the physicochemical characteristics, color, antioxidant activity (AA), total betalains (TB), total polyphenols (TP), and total protein concentration (TPC) were evaluated on stirred yogurt. The treatments (T1-yogurt natural, T2-yogurt added with beet juice, T3-added extract of beet encapsulated with maltodextrin, and T4-yogurt added with extract of beet encapsulated with inulin) exhibited results with significant differences (p < 0.05). The highest TB content was observed in T2 (209.49 ± 14.91), followed by T3 (18.65 ± 1.01) and later T4 (12.96 ± 0.55). The highest AA was observed on T2 after 14 days (ABTS˙ 0.819 mM TE/100 g and DPPH˙ 0.343 mM TE/100 g), and the lowest was found on T1 at day 14 (ABTS˙ 0.526 mM TE/100 g and DPPH˙ 0.094 mM TE/100 g). A high content of TP was observed (7.13 to 9.79 mg GAE/g). The TPC varied between 11.38 to 12.56 µg/mL. The addition of beet extract significantly increased AA in yogurt, betalains being the main compounds responsible for that bioactivity.
... During the fermentation process, kombucha's pH value decreases due to the production of organic acids (Jayabalan et al., 2014). Jayabalan et al. (2007) observed an increase in acetic acid production up to the 15th day of fermentation, reaching a maximum of 9.5 g/L in green tea kombucha. In the case of l-glucuronic acid, the same authors observed a maximum concentration of 2.3 g/L, in black tea kombucha, on the 12th day of fermentation. ...
... However, the authors found that, when comparing their results with other studies, C. sinensis kombuchas have higher vitamin C content, reinforcing the idea that different substrates can influence the beverage final composition. Jayabalan et al. (2007) have observed changes in the content of organic acids and polyphenols in tea and kombucha, prepared from green tea, black tea, and teamanufacturing residues during 18 days of fermentation. The authors have distinguished an increase in organic acids concentration and degradation of the epicatechin isomers in the fermentation process. ...
Article
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Kombucha has been gaining prominence around the world and becoming popular due to its good health benefits. This beverage is historically obtained by the tea fermentation of Camellia sinensis and by a biofilm of cellulose containing the symbiotic culture of bacteria and yeast (SCOBY). The other substrates added to the C. sinensis tea have also been reported to help kombucha production. The type as well as the amount of sugar substrate, which is the origin of SCOBY, in addition to time and temperature of fermentation influence the content of organic acids, vitamins, total phenolics, and alcoholic content of kombucha. The route involved in the metabolite biotransformation identified in kombucha so far and the microorganisms involved in the process need to be further studied. Some nutritional properties and benefits related to the beverage have already been reported. Antioxidant and antimicrobial activities and antidiabetic and anticarcinogenic effects are some of the beneficial effects attributed to kombucha. Nevertheless, scientific literature needs clinical studies to evaluate these benefits in human beings. The toxic effects associated with the consumption of kombucha are still unclear, but due to the possibility of adverse reactions occurring, its consumption is contraindicated in infants and pregnant women, children under 4-years-old, patients with kidney failure, and patients with HIV. The regulations in place for kombucha address a number of criteria, mainly for the pH and alcohol content, in order to guarantee the quality and safety of the beverage as well as to ensure transparency of information for consumers.
... Organik asitlere ek olarak, B1,B2,B6,B12 ve C vitaminlerinin (Greenwalt, Steinkraus, & Ledf, 2000) yanı sıra bakır, demir, mangenez, nikel ve çinko gibi minerallerinde bulunduğu yapılan çalışmalarda tespit edilmiştir. (Jayabalan, Malbasa, Loncar, Vitas, & Sathishkumar 2014).Yapılan araştırmalar incelendiğinde en popüler organik asitler; asetik asit, laktik asit, glukoronik asit, glukonik asit (Jayabalan, Marimuthu, & Swaminathan, , (2007) ;Coton, et al., (2017)). İçeriğinde bulunan ve fermantasyonla birlikte oluşan bazı enzimler, bakteriyel asitler ve ikincil metabolitler karmaşık bir süreç olan detoksifikasyon sürecinde karaciğere destek olarak toksiklerin vucuttan uzaklaştırılmasında kolaylık sağlar (Dufresne & Farnworth, 2000). ...
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Abstract: Drinking the beverage tea has been considered a health-promoting habit since ancient times. Tea is one of the most popular drinks due to its pleasant taste and perceived health effects. Although health benefits have been attributed to tea consumption since the beginning of its history, scientific investigation of this beverage and its constituents has been under way for about 30 years.The health benefits ascribed to the consumption of teas may be related to the high content of bioactive ingredients such as polyphenols. Polyphenols have antioxidant, antiviral, and anti-inflammatory activities; modulate detoxification enzymes; stimulate immune function and decrease platelet aggregation. The major phenolics present in teas are flavan-3-ols and flavonols. Conjugates of quercetin and kaempferol are the main flavonols in tea, with lower levels of myricetin. Other related compounds found in tea are gallic acid and quinic esters of gallic, coumaric, and caffeic acids, together with the purine alkaloids theobromine and caffeine, proanthocyanidins, and trace levels of flavones. The modern medicinal research is providing a scientific basis for this belief. The evidence supporting the health benefits of tea drinking grows stronger with each new study that is published in the scientific literature. Tea consumption has also been shown to be useful for prevention of many debilitating human diseases that include maintenance of cardiovascular and metabolic health. Various studies suggest that polyphenolic compounds present in green and black tea are associated with beneficial effects in prevention of cardiovascular diseases, particularly of atherosclerosis and coronary heart disease. In addition, anti-aging, and many other health beneficial effects associated with tea consumption are described. Keywords: tea, health, antidiabetic, anti-aging,
... Citric acid showed an almost linear increase during the 15 days of fermentation, reaching 1.5 g/L on the last day. According to some authors, citric acid can be produced by Pichia yeasts(Afolabi et al., 2018;Hesham et al., 2020).However, few studies reported citric acid in kombucha, varying between 0.03 and 0.07 g/L(Jayabalan et al., 2007;Neffe-Skocińska et al., 2017). Citric acid can contribute to antimicrobial activity and inactivate oxidative enzymes present in the cultivation medium(Sawant et al., 2018). ...
Article
The production of kombucha generates as fermentation products a beverage and also bacterial cellulose (BC). Despite several studies on the production and characteristics of the beverage, BC from kombucha is still little explored and there are not many reports on the reuse of this material. The main objective of the present study was to demonstrate typical kombucha fermentation results in a satisfactory amount of BC with morphological and physicochemical characteristics similar to those produced in synthetic medium. For this, the fermentation kinetics for obtaining kombucha beverage and bacterial cellulose (BC) were evaluated in a medium containing green tea and sugar. The microbial composition of the culture was identified and Komagataeibacter rhaeticus proved to be the main strain responsible for BC production. The fermentation showed typical behavior with the production of acetic acid, citric acid, ethanol, and a slight increase in total phenolic content and antioxidant activity. The final concentration of 4.56 g/L of BC was obtained and identified as type I, showing a structure of fine tangled fibers and crystallinity of 74.3%. Knowing that there is a high demand for cellulose in many areas, BC produced by the kombucha industry can be an alternative source to the conventional production method.
... The organic acids were identified according to a previous method. 21 High-performance liquid chromatography (HPLC). Epigallocatechin gallate (EGCG), epicatechin gallate (ECG), epigallocatechin (EGC), catechin (C), epicatechin (EC), GA, gluconic acid, glucuronic acid, and acetic acid were identified according to a previous method. ...
Article
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As a popular traditional fermented beverage, kombucha has been extensively studied for its health benefits. However, the science behind the anti-inflammatory effect of kombucha has not been well studied, and there is an urgent need to uncover the secrets of the anti-inflammatory properties of kombucha. Here, we investigate kombucha's protective effects against lipopolysaccharide (LPS)-induced sepsis and on the intestinal microecology in mice. The contents of reducing sugars, polyphenols, catechins, and organic acids in the kombucha group were identified using various methods. The results showed that the concentrations of acetic acid, gluconic acid, polyphenol, and glucuronic acid in the kombucha group were 55.70 ± 2.57 g L-1, 50.20 ± 1.92 g L-1, 2.36 ± 0.31, and 1.39 ± 0.22 g L-1, respectively. The result also demonstrated that kombucha effectively improves the survival rate from 0% to 40%, and increases the thermoregulation in LPS-treated mice, which showed decreased mobility and had lost their appetite for food. Furthermore, kombucha reduced the levels of tumor necrosis factor-α and interleukins (IL)-1β and IL-6, restored the levels of T cells and macrophages in LPS-challenged mice, alleviated the histopathological damage, and inhibited NF-κB signaling in mice with LPS-induced sepsis. We demonstrated that kombucha effectively prevents cellular immune function disorder in mice at the initial stage of sepsis and exerts an immunomodulatory effect. In addition, the effect of kombucha on the gut microbiota was investigated during sepsis. Kombucha supplementation altered the diversity of the gut microbiota and promoted the growth of butyrate-producing bacteria, which exert anti-inflammatory effects. Our results illustrate the potential of kombucha as a novel anti-inflammatory agent against the development of systemic inflammatory responses associated with sepsis.
... Similarly, Jayabalan et al. (2008) reported an increase of 19% in reducing capacity of green tea and 17% in black tea at the finish of the fermentation performed over 18 days. This increase may be related to the degradation of complex phenolic compounds (such as flavonoids) present in the tea samples, due to acid environment and the action of enzymes produced by the microorganisms present in the mixed culture (Jayabalan et al. 2007;Jayabalan et al. 2008). ...
Article
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Kombucha is a non-alcoholic fermented beverage traditionally produced from a sugared tea that presents a sour and refreshing taste This work aimed to develop, characterize and evaluate the sensory acceptance of Kombucha beverages made from oolong, a traditionally tea used for Kombucha production, or yerba mate tea, which is very popular and easily found herb in Brazil. The characterization was related total soluble solids (TSS), sugars, pH, titratable acidity (TA), organic acids (OA), alcohol content (AC), phenolics (PHE), flavonoids (FL), antioxidant activity (AA), besides, the sensory acceptance by potential consumers. Total soluble solids decreased 8.3% in formulation with oolong and 7.0% in formulation with yerba mate tea. The pH ranged from 4.3 and 4.5 to 2.8 and 3.1 after 14 days, respectively. Titratable acidity reached 8.97 g.L-1 in oolong tea and 6.75 g.L-1 in yerba mate tea. Acetic acid was the highest organic acid identified and quantified at the end of fermentation time. Flavonoids decreased during fermentation in both samples, while reducing capacity did not differ throughout fermentation time. Regarding the antioxidant capacity, in the formulations with oolong and yerba mate, it presented higher inhibitory capacity of the ABTS radical of 90.22 and 68.75%, while the DPPH radical inibitory capacity was 89.74% in oolong and 86.72% in yerba mate. Kombucha formulated with yerba mate tea resulted in a sour and refreshing beverage, with higher global acceptance compared to oolong tea, both drinks exhibiting antioxidant potential in vitro.
... Kombuchas from different origins also have other antioxidant activities and polyphenol concentrations due to differences in starter culture microbiome, temperature, and time used between fermentations [62]. The stability of polyphenol content during fermentation was first verified in green and black tea residues, in addition to the production of acetic and glucuronic acid, reaching the maximum levels after 15 days for green tea and after 12 days for black tea [63]. It is essential to highlight that, even though the ability to scavenge free radicals is time-dependent, a prolonged fermentation can accumulate acids at levels potentially harmful to health, which might cause metabolic acidosis [64]. ...
Article
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Fermentation is one of the oldest biotechnological tools employed by mankind. Fermenting food gives them better sensory and nutritional qualities, the latter including vitamins, phenolic compounds, antioxidants, and antimicrobials. Kombucha is the result of the fermentation of a sweetened Camellia sinensis infusion by the action of a symbiotic community of yeasts and bacteria organized in a cellulosic biofilm called SCOBY and has gained great prominence among fermented foods and beverages, with a considerable increase in its popularity in the last decade, both among consumers and within the scientific community. This is explained by the particular functional and microbial characteristics of this beverage, such as its antioxidant and antimicrobial potential, long-term stable microbial communities, its suitability for fermentation under different conditions of time and temperature, and amenability to other carbon sources besides sucrose. Thus, this review aims to present and discuss the functional, microbial, and physicochemical aspects of kombucha fermentation, covering the many challenges that arise in its production, in domestic, commercial, and legislation contexts, and the next steps that need to be taken in order to understand this drink and its complex fermentation process.
... Procedure for the formulation of fermented green tea using tea fungus(Jayabalan et al., 2007) ...
... Its fermentation process also leads to the formation of a floating biofilm on the surface of the growth medium due to the activity of certain strains of AAB [7]. Chemical analysis of kombucha have shown the presence of various organic acids, such as acetic, gluconic, glucuronic, malic, L-lactic, malonic, oxalic and tartaric that are responsible for sour taste [8]; the vitamins: B1,B2, B6, B16, C [9][10]; minerals: Cu, Fe, Mn, Ni, Zn [9]; anions: F-, Cl-, Br-, I-, NO3-, HPO4-, SO4- [11] and polyphenolic compounds [12]. That is why kombucha, thanks to its rich content of active substances and probiotic properties, has a beneficial effect on health. ...
Preprint
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Kombucha is a beverage made by fermenting sugared tea using a symbiotic culture of bacteria belonging to the genus Acetobacter , Gluconobacter , and the yeasts of the genus Saccharomyces along with glucuronic acid, contribute to health protection. The paper presents the evaluation of ferments as a potential cosmetic raw material obtained from Yerba Mate after different fermentation times with the addition of kombucha. Fermented and unfermented extracts were compared in terms of chemical composition and biological activity. Studies of antioxidant properties were carried out using DPPH and ABTS radicals. A significant decrease in the intracellular level of free radicals was also observed. Cytotoxicity was determined on keratinocyte and fibroblast cell lines, resulting in significant increase in cell viability for the ferments. In addition, the ferments showed strong ability to inhibit the activity of lipoxygenase and collagenase and elastase enzymes and long‐lasting hydration after their application on the skin. Extract obtained after 21 days of fermentation contained the highest amount of phenolic acids and xanthines. The results showed that both the analyzed Yerba Mate extract and the ferments obtained with kombucha may be valuable ingredients in cosmetic products.
... These yeasts are seen in symbiotic relations with other starter microbes (acetic acid and lactic acid bacteria). Jayabalan et al. (2007) observed that many acids, like acetic, malic, and citric acids, were highlighted during such fermentation in Kombucha, resulting in its sour tasting and subsequent carbonated, vitamin-rich drink. ...
Chapter
Genus Saccharomyces is one of the most explored yeast species, especially in the food processing and allied food industries. Among them S. cerevisiae, S. boulardii, and S. cerevisiae var. boulardii are the leading yeasts that find relatively major functional usages as natural fermenters in various food applications. As humanity as a whole is on the search for an easy cure into healthy living among their busy schedule, healthy gut, balanced diet, probiotics, and functional/fortified foods have gained immense importance. Yeast and Saccharomyces could play a substantial role in ensuring that such diet balances are maintained by utilizing their natural abilities to ferment food items according to their needs. In this context, this book chapter attempts to survey an overhaul of Saccharomyces in the current food market, food industry, and food technology and their role in food processing industries.
... Plant metabolites, polyphenols and phytochemicals, were molecular families that widely discriminated the microorganisms. It is worth noting that epicatechin gallate was potentially associated to A. indonesiensis and was reported in kombucha by several studies ( Figure 2C) [21,22]. Additionally, B. bruxellensis and H. valbyensis distinguished themselves from the acetic acid bacterium with fatty acids (potentially linoleic and hydroxy stearic acids; Figure 2A,B). ...
Article
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Kombucha is a fermented beverage obtained through the activity of a complex microbial community of yeasts and bacteria. Exo-metabolomes of kombucha microorganisms were analyzed using FT-ICR-MS to investigate their interactions. A simplified set of microorganisms including two yeasts (Brettanomyces bruxellensis and Hanseniaspora valbyensis) and one acetic acid bacterium (Acetobacter indonesiensis) was used to investigate yeast–yeast and yeast–acetic acid bacterium interactions. A yeast–yeast interaction was characterized by the release and consumption of fatty acids and peptides, possibly in relationship to commensalism. A yeast–acetic acid bacterium interaction was different depending on yeast species. With B. bruxellensis, fatty acids and peptides were mainly produced along with consumption of sucrose, fatty acids and polysaccharides. In opposition, the presence of H. valbyensis induced mainly the decrease of polyphenols, peptides, fatty acids, phenolic acids and putative isopropyl malate and phenylpyruvate and few formulae have been produced. With all three microorganisms, the formulae involved with the yeast–yeast interactions were consumed or not produced in the presence of A. indonesiensis. The impact of the yeasts’ presence on A. indonesiensis was consistent regardless of the yeast species with a commensal consumption of compounds associated to the acetic acid bacterium by yeasts. In detail, hydroxystearate from yeasts and dehydroquinate from A. indonesiensis were potentially consumed in all cases of yeast(s)–acetic acid bacterium pairing, highlighting mutualistic behavior.
... Gluconic Acid 39 g/L (day 60) (Chen & Liu, 2000) Colon health, antioxidant (Kaewkod et al., 2019, Bhattacharya et al., 2011 Glucuronic Acid 1.5 ± 0.17 g/L (day 15) (Jayabalan et al., 2007) Liver detoxification, antioxidant (Gaggìa et al., 2019) Ascorbic for performing the aerobic fermentation, part of the cellulosic biofilm is added to the tea sweetened with about 10% sucrose, in addition to 10-15% (v/v) of previously fermented kombucha, and maintained for a period of 7 to 12 days at room temperature (±25 • C) (Jayabalan et al., 2014). At this temperature there is an appropriate balance of the metabolic activities of bacteria and yeast, resulting in a beverage with a balanced flavor between acidity and sweetness (Crum et al., 2016). ...
Article
Plant bioactive compounds have been studied mainly for their beneficial antioxidant properties. Kombucha is a fermented beverage traditionally obtained from fermentation of sweetened black or green tea by a characteristic consortium of yeasts and bacteria. The beverage naturally contains bioactive compounds from teas and their synthesis can be increased during fermentation. This review aims to explore the different bioactive compounds found in kombucha from different substrates, as well as the factors that influence on their synthesis and their amount in the final product. The results suggest phenolic compounds are the main bioactive compounds in kombucha. The substrate type contributes the most to increasing the content of bioactive compounds in the final product; fermentation time and type of sugar also increase the amount of these compounds. Further research suggestions include the combination of strategies to increase bioactive compounds in kombucha, quantification and characterization of the isolated compounds. Free access https://authors.elsevier.com/a/1emYm16Ds1s9uR
... The results prior to the biological assay (Table 1) showed that both kombucha beverages presented high phenols levels and antioxidant properties, with better results for the green tea kombucha when compared to mate tea kombucha. According to Jayabalan et al. (2007), the enzymes released by the microorganisms present in kombucha lead to the biotransformation of epicatechins from green tea, favoring the release of catechins, thus improving the antioxidant activity of the final beverage. ...
Article
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Introduction With the increase of chronic diseases as a consequence of the population's eating habits, there is also a growing interest in foods rich in bioactive compounds capable of mitigating these diseases. Thus, this study aimed to evaluate the effects of supplementation with kombucha and green banana flour (GBF) on Wistar rats fed with cafeteria diet (CAF). Methods The animals were randomized into five groups of seven animals each, which were fed with the following diets: Treatment 1 (T1): Control treatment/commercial feed; Treatment 2 (T2): cafeteria diet (CAF); Treatment 3 (T3): CAF + kombucha; Treatment 4 (T4): CAF + green banana flour (GBF); Treatment 5 (T5): CAF + GBF + kombucha. Daily weight gain, daily food consumption, feed conversion, blood glucose, total cholesterol and fractions, triglycerides, liver enzymes, antioxidant activity, and body composition were evaluated. Results T5 presented lower feed intake and less weight gain. Liver histology revealed vacuolization in all treatments except T1, which was confirmed by the results of liver enzymes. There was no increase in blood glucose, and changes were observed in the lipid profile of the animals. T1 had the lowest body fat and the highest protein levels. Differences were observed for the antioxidant capacity in the liver of animals among treatments. Conclusion The intake of cafeteria diet altered the lipid and liver profile of the animals and the consumption of kombucha and GBF did not prevent these changes. The high polyphenols level of kombucha did not exert a hepatoprotective effect as an antioxidant. However, this supplementation generated greater satiety in the animals, leading to less weight gain until the end of the experiment.
... The fermentation process is initiated by the inoculation of live mother SCOBY to the sugared tea broth. Following that, kombucha tea is added and incubated at room temperature for few weeks (Jayabalan et al., 2007). Kombucha tea or beverage produced during the fermentation is the primary product of choice, with SCOBY biofilm rich in cellulose generated as the by-product (Gargey et al., 2019). ...
Article
The commercialization of by-product of Kombucha SCOBY (Symbiotic consortium of bacteria and yeast) could be the sustainable way of transforming waste into value-added products. This study aims at developing a robust machine learning model for the prediction of SCOBY yield. Concentrations of tea, sucrose, SCOBY, inoculum, pH, temperature, and fermentation time were the input parameters considered. The robustness of the models was studied using correlation coefficient and root mean square error. Among the algorithms studied, XGB (eXtreme Gradient Boosting) was the most resilient model with high accuracy. By hyperparameter tuning and k-fold cross-validations, the model performance was improved to attain an R² value of 0.9048. The relationship between variables was depicted as Pair plot and Pearson correlation matrix. Fermentation temperature was the most influential parameter affecting SCOBY yield. Shapley additive explanations dependence plots and summary plot provided insights on the combined effects of input parameters on the SCOBY yield.
... The increase in phenol content is due to enzymes produced by bacteria and yeast during the fermentation process, which degrade complex compounds. According to Essawet et al. [21], during the fermentation process, there was biotransformation of catechin compounds and other types of polyphenolic compounds by enzymes in the Kombucha culture [22], such as invertase, cellulases, amylases, which can break the complex bonds between phenolic compounds and tissue structures so that the total phenolic increases [21]. This biotransformation process is also influenced by pH because catechin and theaflavin compounds are less stable in tea solutions at pH ≤ 5 [23]. ...
Article
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Kombucha is a fermented tea beverage with the addition of a kombucha starter called SCOBY (Symbiotic Culture of Bacteria and Yeast). This research aimed to know the microbiological, chemical and antibacterial activity from various concentrations of turmeric kombucha. The data result was analyzed by descriptive analysis with one factor of turmeric concentration (0.4%; 0.8%; 1.2%; 1.6%; 2%). The best treatment was selected using Multi-Criteria Decision-Making (MCMD) method with the Simple Additive Weighting (SAW) technique. The best treatment was obtained on turmeric kombucha 0.8%. Based on analysis, the best treatment is turmeric kombucha 0.8% with characteristics as follows: pH 2.92; total acid 0.28%; total phenol 147.45 μg GAE/ml; total sugar 8%, total microbial 2.5 x 10 ⁷ CFU/ml, inhibition zone diameters for E.coli 3.13 mm; whereas black tea kombucha has pH 2.81; total acid 0.58%; total phenol 716.02 μg GAE/ml; total sugar 7.83%, total microbial 1.3 × 10 ⁸ CFU/ml and inhibition zone diameters for E.coli 2.50 mm.
Article
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.
Chapter
This study isolated antibacterial probiotic strains from sour shrimp, a Vietnamese traditional fermented food, and optimized culturing conditions for the chosen strain. Strain V101 was chosen for optimization experiments for its high antagonistic activity and production of strong antibacterial compounds against indicator harmful bacteria – Escherichia coli, and Staphylococcus aureus. Molecular identification of 16S rRNA sequencing showed that V101 strain was Lactobacillus paracasei. Optimization of culturing conditions found that this strain produces the highest biomass and acid accumulation on modified MRS at pH 5.5; temperature 37 °C in 60 h. Under optimum condition, biomass and acid production increased 76.61% and 10.69% respectively, and antibacterial activities against E. coli improved up to 20%. Pilot fermentation of L. paracasei V101 on production Vietnamese pickles, sour shrimp showed that the fermentation process was quicker, tastier, and fermented products could be preserved longer. These findings will be a potential prerequisite for further study on L. paracasei V101 as a strain not only good for food fermentation and preserving but also a helpful probiotic bacteria bring benefits to human health.
Article
The large-scale availability of glucuronic acid for industrial sectors is limited due to involving costly conventional purification strategies. Here, aqueous two-phase system (ATPS) was used as potent economical platform for selective recovery of D-glucuronic acid. Paenibacillus apiarus MTCC 2192 produced extracellular D-glucuronic acid with maximum yield (0.657 mg/ml) during late log phase. D-glucuronic acid was extracted after treating cell free extract with ATPS system consisting 10% PEG and 15% Potassium hydrogen phosphate (PHP) salt. It showed maximum recovery (82.97%) with lower concentration (5%) of high molecular weight of PEG 6000. The increased concentration of PHP-salt from 10 to 25% (w/w) and variation of pH (4–9) favours high recovery of D-glucuronic acid in top phase due to removal of majority of inhibitory protein component. ATPS with 5% PEG 6000 and 25% PHP-salt showed higher recovery of D-glucuronic acid (84.20%) at pH-4 and could be used as low-cost bio-separation tool to fulfil its great demand.
Article
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.
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Kombucha is a fermented beverage composed of a range of natural compounds such as sugars, ethanol, organic acids, and complex microbial communities of bacteria and yeasts. Based on this several biological properties are attributed to this drink. However, the production of kombucha is not standardized and the final composition of the beverage is highly dependent on the raw materials used and the physicochemical parameters adopted in the process. As a consequence, kombuchas not only vary from one producer to another but also from different batches of the same producer, making the assumptions of quality and properties questionable. In this review, we explore the largely unchecked relations between kombucha and its claimed health benefits. A systematic review was also performed to specifically discuss the potential probiotic and prebiotic effects of kombucha. Although several studies report that kombucha present antimicrobial, antioxidant, detoxifying, and hepatoprotective activities, among others, whereas others classify kombucha as a probiotic drink, there is a lack of scientific evidence about the content of probiotics in this drink and its possible role in the intestinal microbiota. These facts highlight the opportunities in researching and modifying the microbiome composition of kombucha, possibly improving the general qualities of this so-called functional drink.
Chapter
Nowadays, the modern living lifestyle made the number of stressful people increasing day by day. This strategy brought up a problem of overusing stress managing pills, whose side effects are weight gains, changes of appetite and sleep habits, frustration, etc. As a result, there is a need for natural antidepressant remedies for the community to reduce such stressful situations. Tea (Camellia sinensis) becomes one of the most popular drinks worldwide because of its effective medicinal properties such as antioxidant, antitumor, antidepression, cancer and cardiovascular diseases prevention, etc. However, fresh tea might be quite bitter due to high tannin content, hard to preserve and insomnia causing. Fortunately, fermented tea could be another better choice as it reduced tannin content, increased fragrant and eye-catching color, together with the richness of γ-aminobutyric acid (GABA), a neuro-benefit compound, could overcome those downsides. In this study, tea was screened for enzyme inactivation conditions, then fermented for good color ratios, lower tannin content, and higher GABA content. Oolong tea inoculated with 8% L. brevis and fermented in 4 days yielded better GABA content than fermentation of Oolong tea with and without Viscozyme L. Under these conditions, fermented tea had a good sensory assessment with color, flavor almost like Pu-erh tea. Other attributions of fermented tea would be TF/TR at 1/9.7, TC at 1.53%, tannin content at 13.72%, and GABA content at 302.38 mg/kg, almost 4 times higher than GABA content in raw material. This finding is a requisite for further production of GABA rich tea to create widely consuming and naturally stress suppressing drinks.
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The inhibition of pancreatic lipase and the associated reduction of lipid absorption has become the most appropriate approach for treating obesity. Meanwhile, katuk (Sauropus androgynus) leaves are rich in polyphenols that act as natural bioactive compounds and are also responsible for the potential effect on metabolic diseases, including inhibition of pancreatic lipase activity. Naturally occurring polyphenols can inhibit pancreatic lipase and consequently affect fat digestion as well as energy intake. Therefore, this study aimed to optimize the inhibitory activity of pancreatic lipase, which plays an essential role in lipid absorption. In fermented katuk (Sauropus androgynus) leaves were brewed following RSM using a Box Behnken design. Data analysis was used to optimize the formulation with a response surface model consisting of three factors namely sucrose concentration ranging from 10-20% b/v, culture 10-20 b/v, as well as fermentation time of 1-5 days. The parameters tested were the percentage inhibition of pancreatic lipase, antioxidant activity, polyphenol, and total acid. Based on the RSM optimization results obtained from the three influencing factors, the optimum conditions were established namely 10.43% w/v sucrose, 10% v/v kombucha culture, and fermentation for 5 days. These conditions yielded the most optimal responses, with the percentage inhibition of pancreatic lipase, antioxidant activity, polyphenol, and total acid being 86.13%, 96.27%, 0.97 mg GAE/mL, and 1.11%, respectively. In general, the results demons-trated that the RSM method of the Box Behnken design and the parameter prediction values obtained using the model equation are in good agreement with the experimental values with at least R2 ≥ 0.8.
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Traditional fermented foods are obtained by a complex consortium of autochthonous microorganisms producing a wide variety of bioactive compounds, thus representing a reservoir of strains with new functional properties. Here, doughs obtained using five different wholegrain flours were singly fermented with selected yeast strains, which were evaluated for their functional traits. Lactate, volatile fatty acids and conjugated linoleic acid isomers produced by fermented doughs were detected by HPLC, while dough anti-inflammatory capacity was measured on human peripheral blood mononuclear cells by flow cytometry. Yeast potential probiotic activity was assessed by evaluating their resistance to simulated gastric and intestinal fluids. For the first time we report evidence of yeast strains producing high levels of the conjugated linoleic acid (CLA) isomer CLA 10-12tc and propionic acid, which are known for their specific health benefits. Moreover, such yeast strains showed an anti-inflammatory capacity, as revealed by a significantly decreased production of the strongly pro-inflammatory cytokine IL-1β. All our Saccharomyces cerevisiae strains were remarkably resistant to simulated gastric and intestinal fluids, as compared to the commercial probiotic strain. The two strains S. cerevisiae IMA D18Y and L10Y showed the best survival percentage. Our novel yeast strains may be exploited as valuable functional starters for the industrial production of cereal-based innovative and health-promoting fermented foods.
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The Medusomyces gisevi (combucha) culture has long been widely used by the population for food purposes, as well as a natural prophylactic and medicinal agent. The detoxification, antioxidant, anti-inflammatory, immunostimulating, hypolipidemic properties etc. are among the proven properties of kombucha. Researches by a number of authors have proven a pronounced bacteriostatic and bactericidal effect of kombucha metabolites against a wide range of pathogenic microorganisms. In this work we conducted research on the fish pickling technology on the basis of vinegar obtained from the cultural liquid of the kombucha. We studied the organoleptic and physicochemical indicators of the experimental pickled fish batches, according to the results of which it was noted that in the course of autoleptic changes when pickling by the proposed method, the proteins undergo a stronger denaturation.
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Huanglongbing (HLB) is a destructive citrus greening disease; no commercially applicable measures exist. ‘LB8‐9’ Sugar Belle® (SB), originally developed for the fresh market, is the most HLB‐tolerant cultivar among commercially available varieties. Due to the limited capacity of the fresh fruit market, there is a need to increase the demand for SB juice. Kombucha is a fermented tea beverage with black tea and sugar, and is considered a healthy drink with an increasing market. Therefore, we aim to study the potential of using SB juice in kombucha production. Regular (black tea with no citrus juice added), Hamlin (black tea with Hamlin juice added), and SB kombucha (black tea with SB juice added) were prepared and analyzed to observe the composition of aroma and taste compounds in the kombuchas. Aroma and taste compounds in the kombuchas were analyzed using gas chromatography–mass spectrometry/olfactometry and liquid chromatography–triple quadrupole mass spectrometry, respectively. For aroma compounds, SB kombucha was characterized by high concentrations of terpenes and their derivatives, which have mandarin‐like aroma characteristics and health benefits such as antidiabetic and antioxidant effects. For taste compounds, SB kombucha contained higher amount of fructose and organic acids, which have the potential to increase the intensity of sweetness and sourness, and flavonoids. This would support the potential benefits of using SB to make kombucha. This study provides valuable information about the aroma and taste compounds in SB kombucha and its potential health benefits, compared with regular and Hamlin kombucha. This experiment provided valuable information on the elevated aroma and taste compounds, their potential health benefits, and the changes of those compounds during kombucha fermentation in ‘LB8‐9’ Sugar Belle® kombucha, compared to regular and Hamlin kombucha. In the absence of an effective cure or therapy for HLB, this can be the first step for developing alternative citrus product to help the citrus industry mitigate the negative impacts from HLB.
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Kombucha is a drink produced by fermentation of sweetened tea due to symbiotic relationship between yeast and acetic acid bacteria species. In this study; pH value, total acidity, alcohol, total phenolic compounds quantities, caffein and some individual compounds contents of kombucha drinks produced using white, black and green tea were determined. At the end of the fermantation, pH and total acidity (% acetic acid) values of kombuchas including white, black and green tea were found 3,11; 3.22; 3.16 and 8,9; 9,2; 9,0, respectively. Total phenolic compund content of kombuchas produced with white tea (736,1 mg GAE/L) was higher than others. The highest amount of compounds analyzed in the kombucha samples were identified as caffeine. Gallic acid (4,76±1,06 mg/L), caffeine (63,47±4,64 mg/L) and epicatechin (1,59±0,06 mg/L) quantities of kombuchas produced with using white tea were found higher than kombuchas produced with using black and green tea.
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Kombucha is a drink produced by fermentation of sweetened tea due to symbiotic relationship between yeast and acetic acid bacteria species. In this study; pH value, total acidity, alcohol, total phenolic compounds quantities, caffein and some individual compounds contents of kombucha drinks produced using white, black and green tea were determined. At the end of the fermantation, pH and total acidity (% acetic acid) values of kombuchas including white, black and green tea were found 3,11; 3.22; 3.16 and 8,9; 9,2; 9,0, respectively. Total phenolic compund content of kombuchas produced with white tea (736,1 mg GAE/L) was higher than others. The highest amount of compounds analyzed in the kombucha samples were identified as caffeine. Gallic acid (4,76±1,06 mg/L), caffeine (63,47±4,64 mg/L) and epicatechin (1,59±0,06 mg/L) quantities of kombuchas produced with using white tea were found higher than kombuchas produced with using black and green tea.
Article
Scale not only affects the taste and color of water, but also increases the risks of osteoporosis and cardiovascular diseases associated with drinking it. As a popular beverage, tea is rich many substances that have considerable potential for scale inhibition, including protein, tea polyphenols and organic acids. In this study, the effect of tea brewing on scale formation was explored. It was found that the proteins, catechins and organic acids in tea leaves could be released when the green tea was brewed in water with sufficient hardness and alkalinity. The tea-released protein was able to provide carboxyl groups to chelate with calcium ions (Ca²⁺), preventing the Ca²⁺ from reacting with the carbonate ions (CO3²⁻). The B rings of catechins were another important structure in the complexation of Ca²⁺ and magnesium ions (Mg²⁺). The carboxyl and hydroxyl groups on the organic acids was able to form five-membered chelating rings with Ca²⁺ and Mg²⁺, resulting in a significant decrease in Ca²⁺ from 100.0 to 60.0 mg/L. Additionally, the hydrogen ions (H⁺) provided by the organic acids consumed and decreased the alkalinity of the water from 250.0 to 131.4 mg/L, leading to a remarkable reduction in pH from 8.93 to 7.73. It further prevented the bicarbonate (HCO3⁻) from producing CO3²⁻ when the water was heated. The reaction of the tea constituents with the hardness and alkalinity inhibited the formation of scale, leading to a significant decrease in turbidity from 10.6 to 1.4 NTU. Overall, this study provides information to help build towards an understanding of the scale inhibition properties of tea and the prospects of tea for anti-scaling in industrial applications.
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One defining goal of microbiome research is to uncover mechanistic causation that dictates the emergence of structural and functional traits of microbiomes. However, the extraordinary degree of ecosystem complexity has hampered the realization of the goal. Here we developed a systematic, complexity-reducing strategy to mechanistically elucidate the compositional and metabolic characteristics of microbiome by using the kombucha tea microbiome as an example. The strategy centered around a two-species core that was abstracted from but recapitulated the native counterpart. The core was convergent in its composition, coordinated on temporal metabolic patterns, and capable for pellicle formation. Controlled fermentations uncovered the drivers of these characteristics, which were also demonstrated translatable to provide insights into the properties of communities with increased complexity and altered conditions. This work unravels the pattern and process underlying the kombucha tea microbiome, providing a potential conceptual framework for mechanistic investigation of microbiome behaviors.
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Kombucha is a beverage made by fermenting sugared tea using a symbiotic culture of bacteria belonging to the genus Acetobacter, Gluconobacter, and the yeasts of the genus Saccharomyces along with glucuronic acid, which has health-promoting properties. The paper presents the evaluation of ferments as a potential cosmetic raw material obtained from Yerba Mate after different fermentation times with the addition of Kombucha. Fermented and unfermented extracts were compared in terms of chemical composition and biological activity. The antioxidant potential of obtained ferments was analyzed by evaluating the scavenging of external and intracellular free radicals. Cytotoxicity was determined on keratinocyte and fibroblast cell lines, resulting in significant increase in cell viability for the ferments. The ferments, especially after 14 and 21 days of fermentation showed strong ability to inhibit (about 40% for F21) the activity of lipoxygenase, collagenase and elastase enzymes and long‐lasting hydration after their application on the skin. Moreover, active chemical compounds, including phenolic acids, xanthines and flavonoids were identified by HPLC/ESI–MS. The results showed that both the analyzed Yerba Mate extract and the ferments obtained with Kombucha may be valuable ingredients in cosmetic products.
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Abstract In this study, physicochemical, microbiological, and sensory properties, antibacterial and antifungal effects of kombucha teas produced with some small berry fruits (blackberry, raspberry, and red goji berry) were investigated. During fermentation, titratable acidity and pellicle biomass weights increased whereas water activity, brix, viscosity, L* and b* values decreased. At the end of fermentation, the highest minerals determined in the samples were potassium and magnesium. Also, catechin and gallic acid were detected in all samples. Samples produced with blackberry were the most appreciated ones in all criteria. The highest antibacterial and antifungal effects were determined in samples containing blackberries on Staphylococcus aureus and Rhizopus nigricans (24.36 and 20.53 mm zone diameters). The antibacterial effect, MIC, and MBC values (0.023 and 0.016 mg/L) on Staphylococcus aureus. Regarding the antifungal effect, the MIC and MFC values were determined in tea produced with blackberry on Rhizopus nigricans with 0.035 mg/L, and 0.023 mg/L.
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Kombucha is a SCOBY-fermented tea beverage known for its taste, sensorial qualities, and high endogenous microbial load. In recent years, kombucha has become a popular functional food with a compound annual growth rate of 25% from 2015 to 2020 in American kombucha sales alone, and sales are predicted to keep increasing significantly over the next decade. However, kombucha is lacking in scientific research, and there is still much to be explored regarding its safety and native probiotic content. This research looked into the various routes of contamination of several kombucha systems as well as the feasibility of the producing a kombucha beverage with health-promoting characteristics derived from the inclusion of lactic probiotics. Although bacterial spore contamination and survival in the kombucha SCOBY have been documented, it is unknown whether spores can survive in the liquid, or whether they can be transmitted to daughter SCOBYs. The foodborne pathogen and spore-former Bacillus cereus was inoculated into the SCOBY, unfermented liquid, and fermented liquid of three different kombucha systems. Data suggest that neither the route of contamination nor the kombucha system influenced the transmission or survival of B. cereus spores. The spread of the spores between culture and liquid across generation was shown to be sporadic but possible, so hygienic handling of kombucha cultures and raw materials throughout the entire production process is crucial to prevent uptake of pathogenic organisms. There was no survival of B. cereus spores after short-term storage or secondary fermentation, indicating that implementation of a holding step may mitigate potential food safety threats. Kombucha is perceived to contain probiotics, but not all live cultures comprise probiotics. Some commercial kombucha products have validated probiotic strains added to them post-fermentation, but this can be costly. If probiotics, such as lactic acid bacteria, are inoculated into sweet tea prior to fermentation, they may be able to acidify the tea, replacing the need for utilizing previous kombucha or acetic acid, or survive and/or produce beneficial metabolites during fermentation in great enough amounts to convey a health benefit upon consumption. The survivability of six probiotic Lactobacillus sp. in acidified, sweetened tea at 25ºC during kombucha fermentation was established, and the medium (tea) and temperature (25ºC) were both revealed to affect the growth rates of the bacteria. Differences in pH indicated that the probiotics were unable to acidify the tea pre-fermentation. Although survival during fermentation was possible for four out of the six probiotics, it was concluded that probiotic Lactobacillus sp. are not well suited for a probiotic kombucha beverages, but out of the tested probiotics, Lactobacillus brevis and Lactobacillus fermentum were the most promising candidates.
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Eggs are likely to be used in agriculture because they can provide enough nutrients for crop growth. Statistics show that a large number of eggs are lost due to breakage before reaching the final consumer. The purpose of this study was to make a natural liquid fertilizer as a substitute for chemical fertilizers using broken eggs as a resource and to evaluate the efficiency of the formulated fertilizer. To make the liquid fertilizer, the broken eggs and distilled water were mixed at ratios of 6 : 4 and 4 : 6. Then, effective microorganisms (EM) and sugar were added, and the mixture was fermented. The temperature and electrical conductivity (EC) increased gradually with the fermentation while the pH decreased. When evaluated following the seed germination index method of the compost, it was found that the fertilizer matured 10 days after the beginning of the experiment. The growth experiment was conducted with lettuce in which the fermented liquid fertilizer was compared with a commercial liquid fertilizer. The 6 : 4 treatment produced plants with the densest fresh shoot and roots weighing 41.6 and 4.6 g, respectively. The number of leaves (12.3 per plant) was also the highest for the 6 : 4 treatment. Soil analysis showed that the soil pH was improved, and the soil organic matter was increased in the fermented liquid fertilizer treatment.
Article
The study was carried out to investigate the changes of antioxidant properties and quality of green coffee beans fermented by using Bacillus subtilis and Saccharomyces cerevisiae as starter cultures in sugarcane and banana juice at different times fermentation. The fermentations were conducted with different juice concentrations for different fermentation times 24, 48, and 72 hours at room temperature. Antioxidant properties were determined by Folin-Ciocalteu reagent for the determination of total phenolic content, DPPH assay for the determination of antioxidant capacity, and colorimetric method used for determination of total flavonoid content. As a result, coffee fermentation at 10oBrix, 107 cells/mL for each type of microbe, and the time (48 hours) had a positive effect on antioxidant properties. However, there was not a significant difference in terms of antioxidant properties between fermented and original coffee beans at optimal conditions. Therefore, antioxidant properties were dramatically reduced during the early stages of fermentation, but it was shown to be able to overcome it through this study. This study is a premise to applying microbial products through fermentation to create a coffee with high antioxidant activity compared to conventional coffee products.
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Abstract Background Inflammatory diseases are a real scourge of contemporary times. Chronic inflammation is the result of dysbiosis, increased intestinal permeability and activation of the immune system. Its causes are sought in the widespread Western diet, which is claimed to elicit an adverse effect on the microbiota composition and balance in the intestinal ecosystem. Therefore, one of the means to assure good health condition is to maintain the function of the intestinal barrier. Recent reports have indicated the role of fermented foods and bioactive food compounds in shaping microbiota, alleviating inflammation, and restoring homeostasis. Although the human body has developed certain natural mechanisms to ensure body homeostasis, like e.g. autophagy, understanding the role of food in managing this process is a needed line of research. Scope and approach This review article discusses the current knowledge about fermented food and its role in maintaining the integrity of the intestinal barrier. It emphasizes the role of fermented products and bioactive food compounds in alleviating inflammation and indicates the importance of the autophagy process in maintaining homeostasis in the intestinal epithelium. Finally, it highlights the need for further studies into the role of food in managing processes that affect gut balance. Key findings and conclusions: The presented overview of recent scientific reports indicates the role of fermented products in modulating microbiota composition and of bioactive food ingredients in autophagy activation. However, most of the reported studies were performed in vitro or in a rodent model. Thus, their results should not be extrapolated to humans. Because of the lack of comprehensive studies in this respect, there is a need for further, well-designed research to understand the molecular mechanisms by which food ingredients affect health.
Article
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.
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The tea fungus (commonly designed as ''kombucha'') is a symbiotic culture of at least three microorganisms : the acetic acid bacteria Acetobacter xylinum and two yeasts Zygosaccharomyces rouxii and Candida sp. in sugared tea (Hesseltine, 1965; Anonymous, 1983). These microorganisms were cultured in their traditional medium and several metabolites were identified and quantified : ethanol, lactic, acetic, gluconic and glucuronic acids. The antibacterial product known as usnic acid was also searched.
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The effect of Kombucha tea (KT) on oxidative stress induced changes in rats subjected to chromate treatment are reported. KT feeding alone did not show any significant change in malondialdehyde (MDA) and reduced glutathione (GSH) levels, but did enhance humoral response and delayed type of hypersensitivity (DTH) response appreciably over control animals. Chromate treatment significantly enhanced plasma and tissue MDA levels, decreased DTH response considerably, enhanced glutathione peroxidase and catalase activities; however, no change in GSH, superoxide dismutase and antibody titres was noticed. KT feeding completely reversed the chromate-induced changes. These results show that Kombucha tea has potent anti-oxidant and immunopotentiating activities.
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Mucinous neoplasms occur rarely in association with cystic teratoma, Sertoli-Leydig cell tumor, granulosa cell tumor or carcinoid tumor. Several cases of an ovarian stromal tumor with minor sex-cord elements have been reported in the literatures. However, there has been no report about an ovarian mucinous neoplasm coexisting with a stromal tumor with sex-cord elements yet. We report a case of an ovarian neoplasm composed of both mucinous cystadenoma and stromal tumor with minor sex-cord elements in a 58-yr-old female. The ovary including the mass measured 5 cm in size. On section, it revealed an unilocular cyst (4.5 cm in diameter) filled with mucinous fluid. There was a round, yellow, solid nodule, 1.5 cm in diameter within the wall. Microscopically, the cyst was lined by a single layer of endocervical mucinous epithelium and the nodule was composed of spindle cells showing an intersecting and whorled arrangement. There were cell nests showing polygonal shape with abundant cytoplasm among the spindle cells. They showed immunoreactivity for inhibin and did not have any connection with the adjacent mucinous epithelium. Therefore, we interpret the mucinous cystadenoma as having arisen de novo.
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Kombucha tea (KT) is a popular health beverage and is used as an alternative therapy. KT is prepared by placing the kombucha culture in solution of tea and sugar and allowing to ferment. The inoculum is a fungus consisting of symbiotic colony of yeast and bacteria. KT is consumed in several countries and is believed to have prophylactic and therapeutic benefits in a wide variety of ailments, viz., intestinal disorders, arthritis, ageing and stimulation of immunological system. Though KT is used in several parts of the world its beneficial effects and adverse effects have not been scientifically evaluated. Since there are no animal toxicological data on KT, subacute oral toxicity study was carried out. Five groups of rats were maintained: (a) control group given tap water orally, (b) KT given 2 ml/kg orally, (c) plain tea (PT) given 2 ml/kg orally, (d) KT given in drinking water, 1% (v/v) and (e) PT given in drinking water, 1% (v/v). The rats were given this treatment daily for a period of 90 days. Weekly records of weight, feed intake, water intake and general behaviour were monitored. There was no significant difference in the growth of the animals as evidenced by the progressive body weight change. The organ to body weight ratio and histological evaluation did not show any toxic signs. The haematological and biochemical variables were within the clinical limits. The study indicates that rats fed KT for 90 days showed no toxic effects.
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The objective of the study was to evaluate toxicity, anti-stress activity and hepato-protective properties of Kombucha tea. Kombucha tea was fed orally for 15 days using three different doses i.e. normal dose, five and ten times the dose. Rats were then sacrificed and various biochemical, and histological parameters were estimated. Anti-stress activity was evaluated either by 1) by exposing animals to cold and hypoxia and estimating the levels of malondialdehyde and reduced glutathione in plasma/blood or 2) by subjecting the animals to restraint stress and recording faecal output. Hepato-toxicity was induced by challenging the animals to an acute dose of paracetamol (1 gm/kg) orally and determining the plasma levels of SGPT, SGOT and MDA. The effect of oral administration of different doses of K-tea to albino rats was examined and the results indicate that K-tea has no significant toxicity as revealed by various biochemical and histopathological parameters. K-tea has been found to prevent lipid peroxidation and fall in reduced glutathione level when rats were exposed to cold and hypoxia in simulated chamber. Further, K-tea has also been found to decrease the Wrap-restraint faecal pellet output in rats. K-tea has also been found to decrease paracetamol induced hepatotoxicity significantly. The study shows that K-tea has anti-stress and hepato-protective activities.
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In this study, the possibility of using tea production waste as a new casing material in mushroom (Agaricus bisporus) cultivation was investigated. Some physical and chemical characteristics of tea waste, fermented tea waste and a mixture of tea waste with peat were compared with that of peat casing, as were their effects on yield. The highest yield was obtained from peat casing. Using tea production waste alone as a casing was not acceptable for assured yield when it was compared with peat. But, a mixture of tea production waste with peat in 1:1 (v:v) ratio increased the yield. There was no significant difference between the mushroom yields of tea production waste+peat and peat casing materials at the end of 30 and 40 days. High salt content, organic and inorganic compounds in casing materials caused reduction of yields. However, a high iron content in casing material gave a significant positive correlation with total yield at 40 days.
Article
Green tea catechins (GTC) and theaflavins (TF) possess a variety of biological activities. The present study focused on stability of GTC and TF in various solutions and drinks. It was observed that both GTC and TF were vulnerable to degradation caused by elevation of temperature and pH of incubation media. In general, GTC was more stable than TF. When boiled in water, four GTCs showed similar rates of degradation, but in sodium phosphate buffer (pH7.4) at room temperature, four GTCs demonstrated varying stability, with epigallocatechin gallate (EGCG) and epigallocatechin (EGC) being completely degraded in 6 h of incubation, while epicatechin (EC) and epicatechin gallate (ECG) were only degraded by less than 35%. Four TFs also demonstrated varying stability, with theaflavin-3,3′-digallate (TF3) and theaflavin-3′-gallate- B (TF2B) in general being more stable than theaflavin-1 (TF1) and theaflavin-3-gallate-A (TF2A) in either boiling water or alkaline sodium phosphate buffer. When incubated in various solutions and soft drinks, both GTC and TF had poor long-term stability and decayed by at least 50% during the first month of storage at room temperature.
Article
Kombucha is a refreshing beverage obtained by the fermentation of sugared tea with a symbiotic culture of acetic bacteria and fungi, consumed for its beneficial effects on human health. Research conducted in Russia at the beginning of the century and testimony indicate that Kombucha can improve resistance against cancer, prevent cardiovascular diseases, promote digestive functions, stimulate the immune system, reduce inflammatory problems, and can have many other benefits. In this paper, we report on studies that shed more light on the properties of some constituents of Kombucha. The intensive research about the effects of tea on health provide a good starting point and are summarized to get a better understanding of the complex mechanisms that could be implicated in the physiological activity of both beverages.
Article
Tea, an extract of the leaves of the plant Camellia sinensis, has been considered a medicine and healthful beverage for ages. The beneficial effects of tea are thought to be due to its polyphenolic components. Herein, we discuss the present status of tea as a possible cancer chemopreventive agent, covering basic chemistry and biochemical activity of tea, pharmacokinetics of major tea components, studies in animal and cell lines, epidemiological investigations, and future challenges. Tea is one of the few chemopreventive agents known to have protective effects at different stages of the carcinogenic process. Tea constituents may inhibit this process by modulating signal transduction pathways leading to the inhibition of cell proliferation and transformation and enhancement of apoptosis. These activities may or may not be due to the antioxidative activity of tea polyphenols. The bioavailability and tissue levels of tea polyphenols is a key topic to be studied in order to understand the mechanisms of action of tea and its possible protection against cancer in humans.
Article
Green tea catechins (GTCs) as a mixture of (−)-epicatechin (EC), (−)-epicatechin gallate (ECG), (−)-epigallocatechin (EGC), and (−)-epigallocatechin gallate (EGCG) possess a variety of biological activities. We have previously studied the stability of GTCs either as a mixture or as individual epicatechin derivatives in various pH, demonstrating that GTCs as a mixture in alkaline solutions were extremely unstable and degraded almost completely in a few minutes, whereas in acidic solutions (pH < 4) they were very stable. For the pH ranging from 4 to 7, the stability of GTCs was inversely associated with the pH value of the incubation solutions. The present study examined the effect of ascorbic acid and citric acid on the stability of GTCs incubated in sodium phosphate buffer (pH = 7.42). Ascorbic acid added to the incubation mixture significantly increased the stability of GTCs whereas citric acid exhibited no effect. Four epicatechin derivatives examined demonstrated varying stability, with EGCG and EGC being equally instable and EC and ECG being relatively stable. The addition of ascorbic acid significantly increased the stability of all four derivatives, particularly EGC and EGCG. The present results, although not directly transferable to in vivo conditions, may suggest that the presence of ascorbic acid may stabilize the GTCs in the intestine where the pH is neutral or alkaline before absorption. Keywords: Catechin; epicatechin, epicatechin gallate; epigallocatechin gallate; epigallocatechin; longjing tea
Article
Green tea catechins (GTCs), which include (−)-epicatechin (EC), (−)-epicatechin gallate (ECG), (−)-epigallocatechin (EGC) and (−)-epigallocatechin gallate (EGCG), possess a variety of biological activities. We have previously studied the effect of dietary GTCs as a mixture on membrane oxidation of red blood cells and found that GTCs were partially absorbed and detected in the blood of rats given an oral ingestion of 100 mg of GTCs. To explain the partial absorption of GTCs and their varying free-radical scavenging capacity at different pH, the present paper was to study further the pH stability of these GTC isomers because there is a sharp increase in pH from the acidic stomach to the slightly alkaline intestine. Longjing GTCs as a mixture in alkaline solutions (pH > 8) were extremely unstable and degraded almost completely in a few minutes, whereas in acidic solutions (pH < 4) they were very stable. For the pH between 4 and 8, the stability of GTCs was pH-dependent, i.e., the lower the pH, the greater the stability. Four epicatechin isomers examined demonstrated varying stability in alkaline solutions with EGCG and EGC being equally instable, and EC and ECG being relatively stable. The present results suggest that part of the mechanism by which GTCs were partially absorbed may be attributed to instability of EGCG and EGC in the intestine where the pH is neutral or alkaline. Keywords: Epicatechin; epicatechin gallate; epigallocatechin gallate; epigallocatechin; longjing tea
Article
Further applications of a spectrophotometric method are described for the determination of polyphenolic oxidation products in black tea liquors for the assessment of quality in tea. In addition to calculating theaflavin and thearubigin contents from optical density measurements at 380 mu, values for total colour and brightness have been calculated from optical density measurements at 460 mu. Confirmation has been obtained that theaflavin content is an extremely important factor in determining quality in black tea, and in determining ‘brightness’ in tea infusions. Thearubigins contribute to colour and strength. The effects of seasonal variations and of methods of manufacture on the composition of tea have been examined. Changes in composition during storage of tea under adverse conditions of temperature and moisture content have been related to losses of quality. The effects of the composition of the water used on the composition and colour of tea infusions are also indicated.
Article
Variation in polyphenot oxidase activity and levels of total polyphenols and catechins with respect to different clones and shoot components, and its effect on quality of black tea (Camellia sinensis (L) 0 Kuntze, were studied. There was a wide variation in polyphenol oxidase activity of the different clones tested. The optimum fermentation time and polyphenol oxidase activity of different clones exhibited a hyperbolic relationship, viz y = 2.36 + 1129/x, where y = optimum fermentation time in minutes and x = polyphenol oxidase activity in μM catechol oxidised g−1 acetone powder min−1, with an r value of −0.98, which is signi Jicant at P ≤ 0.001. A good non-linear relationship was found between polyphenol oxidase activity of ji-esh tea shoots of different clones and the theajavins content of corresponding black teas. Among different shoot components, bud and first leaf had higher levels of polyphenols and catechins than internodes. However, the polyphenol oxidase activity showed a reverse trend: the internodes exhibited a higher enzyme activity compared with other components. Formation of theajavins during fermentation of different shoot components was in good agreement with polyphenol oxidase activity. High performance liquid chromatographic analysis of the theaflavins fraction in tea brew of black teas made from different components of tea shoot showed that buds resulted in black tea with the highest amount of theaflavin gallates, whereas teas produced from internodes had the lowest amount of theaflavin gallates. A new factor, viz theaflavin digallate equivalent, was developed, and the significance of this factor for chemical evaluation of black tea quality is discussed in this paper.
Article
The tea fungus is a symbiosis of osmophilic yeasts (mainly Schizosaccharomyces pombe, Saccharomycodes ludwigii, Pichia spec.) and acetic acid bacteria (Acetobacter xylinum, A. xylinoides, Bacterium gluconicum) used to produce teakwass with sugared black tea as substrate. The influence of the following sugars on the production of ethanol and lactic acid was studied using enzymatic tests: sucrose, lactose, glucose and fructose. Maximal yields of ethanol were recorded with 150 g fructose/l (8.11 g ethanol/l and 50 g sucrose/l (6.3 g ethanol/l). Lactose and glucose yielded only minor amounts of ethanol. Lactic acid was produced in relatively high concentrations with 50 sucrose/l (0.9 g acid/l); the other sugars in all tested concentrations stimulated the synthesis of this acid only to a moderate degree. The pH values of the teakwass preparations generally dropped during incubation as a result of acid formation. Test persons estimated the teakwass products as refreshing with a fruitlike taste within 6 to 10 days of incubation; prolongation of fermentation yielded a distinctly sour flavour like vinegar.
Article
Tea is one of the most popular beverages consumed worldwide. The relationship between tea consumption and human cancer incidence is an important concern. This topic has been studied in different populations by many investigators, but no clear-cut conclusion can be drawn. Whereas some studies have shown a protective effect of tea consumption against certain types of cancers, other studies have indicated an opposite effect. Our purpose is to provide a critical review of this topic, covering basic chemistry and biochemical activity of tea, epidemiologic investigations, and laboratory studies, as well as possible directions for future research. Studies have demonstrated either a lack of association between tea consumption and cancer incidence at specific organ sites or inconsistent results. On the other hand, many laboratory studies have demonstrated inhibitory effects of tea preparations and tea polyphenols against tumor formation and growth. This inhibitory activity is believed to be mainly due to the antioxidative and possible antiproliferative effects of polyphenolic compounds in green and black tea. These polyphenolics may also inhibit carcinogenesis by blocking the endogenous formation of N-nitroso compounds, suppressing the activation of carcinogens, and trapping of genotoxic agents. The effect of tea consumption on cancer is likely to depend on the causative factors of the specific cancer. Therefore, a protective effect observed on a certain cancer with a specific population may not be observable with a cancer of a different etiology. On the basis of this concept, we suggest future laboratory and epidemiologic studies to elucidate the relationship between tea consumption and human cancer risk.
Article
This article summarizes available data on the chemopreventive efficacies of tea polyphenols, curcumin and ellagic acid in various model systems. Emphasis is placed upon the anticarcinogenic activity of these polyphenols and their proposed mechanism(s) of action. Tea is grown in about 30 countries and, next to water, is the most widely consumed beverage in the world. Tea is manufactured as either green, black, or oolong; black tea represents approximately 80% of tea products. Epidemiological studies, though inconclusive, suggest a protective effect of tea consumption on human cancer. Experimental studies of the antimutagenic and anticarcinogenic effects of tea have been conducted principally with green tea polyphenols (GTPs). GTPs exhibit antimutagenic activity in vitro, and they inhibit carcinogen-induced skin, lung, forestomach, esophagus, duodenum and colon tumors in rodents. In addition, GTPs inhibit TPA-induced skin tumor promotion in mice. Although several GTPs possess anticarcinogenic activity, the most active is (–)-epigallocatechin-3-gallate (EGCG), the major constituent in the GTP fraction. Several mechanisms appear to be responsible for the tumor-inhibitory properties of GTPs, including enhancement of antioxidant (glutathione peroxidase, catalase and quinone reductase) and phase II (glutathione-S-transferase) enzyme activities; inhibition of chemically induced lipid peroxidation; inhibition of irradiation-and TPA-induced epidermal ornithine decarboxylase (ODC) and cyclooxygenase activities; inhibition of protein kinase C and cellular proliferation; antiinflammatory activity; and enhancement of gap junction intercellular communication. Curcumin is the yellow coloring agent in the spice turmeric. It exhibits antimutagenic activity in the Ames Salmonella test and has anticarcinogenic activity, inhibiting chemically induced preneoplastic lesions in the breast and colon and neoplastic lesions in the skin, forestomach, duodenum and colon of rodents. In addition, curcumin inhibits TPA-induced skin tumor promotion in mice. The mechanisms for the anticarcinogenic effects of curcumin are similar to those of the GTPs. Curcumin enhances glutathione content and glutathione-S-transferase activity in liver; and it inhibits lipid peroxidation and arachidonic acid metabolism in mouse skin, protein kinase C activity in TPA-treated NIH 3T3 cells, chemically induced ODC and tyrosine protein kinase activities in rat colon, and 8-hydroxyguanosine formation in mouse fibroblasts. Ellagic acid is a polyphenol found abundantly in various fruits, nuts and vegetables. Ellagic acid is active in antimutagenesis assays, and has been shown to inhibit chemically induced cancer in the lung, liver, skin and esophagus of rodents, and TPA-induced tumor promotion in mouse skin. Ellagic acid functions through a variety of mechanisms, including inhibition of microsomal P-450 enzymes, stimulation of glutathione-S-transferase, scavenging the reactive metabolites of carcinogens, and direct binding to DNA, thus potentially masking sites that would normally interact with ultimate carcinogens. GTP, curcumin and ellagic acid exhibit potent antioxidant effects. This property, coupled with their other effects, make them effective chemopreventives against both the initiation and promotion/progression stages of carcinogenesis.
Article
A high-performance liquid chromatography method employing diode array detection was developed to determine levels of the major catechins present in black, green, and Jasmine tea infusions. Reversed-phase separations were performed on a C18 column using three gradients: acetonitrile-acetate buffer, methanol-acetate buffer, and acetonitrile-acetate buffer with ascorbic acid. The identities of the tea catechins were established by comparing absorbance spectra and retention times to reference standards chromatographed under identical conditions. Epicatechin, epigallocatechin, epicatechin gallate, and epigallocatechin gallate were found in all the tea infusions examined, ranging in concentration from 1-13 mg dl-1. These levels indicate that even moderate tea consumption can contribute a substantial quantity of flavanols to the diet. Although some differences between the three brewed teas were evident, all were comparably good sources of these catechins.
Article
Kombucha was prepared in a tea broth (0.5% w/v) supplemented with sucrose (10% w/v) by using a commercially available starter culture. The pH decreased steadily from 5 to 2.5 during the fermentation while the weight of the "tea fungus" and the OD of the tea broth increased through 4 days of the fermentation and remained fairly constant thereafter. The counts of acetic acid-producing bacteria and yeasts in the broth increased up to 4 days of fermentation and decreased afterward. The antimicrobial activity of Kombucha was investigated against a number of pathogenic microorganisms. Staphylococcus aureus, Shigella sonnei, Escherichia coli, Aeromonas hydrophila, Yersinia enterolitica, Pseudomonas aeruginosa, Enterobacter cloacae, Staphylococcus epidermis, Campylobacter jejuni, Salmonella enteritidis, Salmonella typhimurium, Bacillus cereus, Helicobacterpylori, and Listeria monocytogenes were found to be sensitive to Kombucha. According to the literature on Kombucha, acetic acid is considered to be responsible for the inhibitory effect toward a number of microbes tested, and this is also valid in the present study. However, in this study, Kombucha proved to exert antimicrobial activities against E. coli, Sh. sonnei, Sal. typhimurium, Sal. enteritidis, and Cm. jejuni, even at neutral pH and after thermal denaturation. This finding suggests the presence of antimicrobial compounds other than acetic acid and large proteins in Kombucha.
Article
Changes in major components and microbes in tea fungus broth (or kombucha; teakwass) prepared from nine different sources during a prolonged fermentation of up to 60 days were investigated. Cell concentrations of both yeasts and acetic acid bacteria in broth were generally higher than those in the cellulosic pellicles. The residual sucrose concentration decreased linearly with time, although the rate fell after the first month. Metabolic fates of glucose and fructose produced as a result of the hydrolysis of sucrose were different. Glucose was not produced in parallel with fructose (0.085 g 100 ml(-1) d(-1)) but was produced with a lower initial rate (0.041 g 100 ml(-1) d(-1)). Both titratable acidity and gluconic acid increased steadily with time for all samples, although gluconic acid was not generated for 6 days until the fermentation had begun. Acetic acid increased slowly to a maximum value of 1.1 g 100 ml(-1) after 30 days; thereafter, it decreased gradually. Gluconic acid contributed to the titratable acidity and thus, the taste of tea fungus broth, during the final stage of fermentation. It is concluded that the desired quality or composition of kombucha can be obtained through the proper control of fermentation time.
Article
Green tea cateachins (GTC). namely (-) epicatechin (EC), (-) epicatechin gallate (ECG), (-) epigallocatechin (EGC), and (-) epigallocatechin gallate (EGCG), have been studied extensively for their wide-ranging biological activities. The goal of the present study was to examine the stability of GTC as a mixture under various processing conditions. The stability study demonstrated that GTC was stable in water at room temperature. When it was brewed at 98 degrees C for 7 h, longjing GTC degraded by 20%. When longjing GTC and pure EGCG were autoclaved at 120 degrees C for 20 min, the epimerization of EGCG to (-) gallocatechin gallate (GCG) was observed. The relatively high amount of GCG found in some tea drinks was most likely the epimerization product of EGCG during autoclaving. If other ingredients were absent, the GTC in aqueous solutions was pH-sensitive: the lower the pH, the more stable the GTC during storage. When it was added into commercially available soft drinks or sucrose solutions containing citric acid and ascorbic acid, longjing GTC exhibited varying stability irrespective of low pH value. This suggested that other ingredients used in production of tea drinks might interact with GTC and affect its stability. When canned and bottled tea drinks are produced, stored, and transported, the degradation of GTC must be taken into consideration.
Article
Tea has received a great deal of attention because tea polyphenols are strong antioxidants, and tea preparations have inhibitory activity against tumorigenesis. The bioavailability and biotransformation of tea polyphenols, however, are key factors limiting these activities in vivo. The inhibition of tumorigenesis by green or black tea preparations has been demonstrated in animal models on different organ sites such as skin, lung, oral cavity, esophagus, forestomach, stomach, small intestine, colon, pancreas, and mammary gland. Epidemiological studies, however, have not yielded clear conclusions concerning the protective effects of tea consumption against cancer formation in humans. The discrepancy between the results from humans and animal models could be due to 1) the much higher doses of tea used in animals in comparison to human consumption, 2) the differences in causative factors between the cancers in humans and animals, and 3) confounding factors limiting the power of epidemiological studies to detect an effect. It is possible that tea may be only effective against specific types of cancer caused by certain etiological factors. Many mechanisms have been proposed for the inhibition of carcinogenesis by tea, including the modulation of signal transduction pathways that leads to the inhibition of cell proliferation and transformation, induction of apoptosis of preneoplastic and neoplastic cells, as well as inhibition of tumor invasion and angiogenesis. These mechanisms need to be evaluated and verified in animal models or humans in order to gain more understanding on the effect of tea consumption on human cancer.
Article
During olive oil production, large quantities of olive mill wastewater (OMW) are produced. This wastewater material, containing a high level of phenolic compounds, poses a serious environmental problem in almost all Mediterranean countries. Candida tropicalis YMEC14 was used as an extremophile strain to design an aerobic biotreatment process to detoxify OMW and reduce its polluting organic load. The process was enhanced by directing yeast metabolism towards biodegradation pathways using hexadecane as co-metabolite and by immobilizing yeast cells in calcium alginate beads. Under immobilization conditions, C. tropicalis YMEC14 grown at 40 degrees C in OMW supplemented with hexadecane resulted in 69.7%, 69.2% and 55.3% reduction of chemical oxygen demand, monophenols and polyphenols, respectively, after a 24-h fermentation cycle.
Article
Since 1922 when Wu proposed the use of the Folin phenol reagent for the measurement of proteins (l), a number of modified analytical pro- cedures ut.ilizing this reagent have been reported for the determination of proteins in serum (2-G), in antigen-antibody precipitates (7-9), and in insulin (10). Although the reagent would seem to be recommended by its great sen- sitivity and the simplicity of procedure possible with its use, it has not found great favor for general biochemical purposes. In the belief that this reagent, nevertheless, has considerable merit for certain application, but that its peculiarities and limitations need to be understood for its fullest exploitation, it has been studied with regard t.o effects of variations in pH, time of reaction, and concentration of react- ants, permissible levels of reagents commonly used in handling proteins, and interfering subst.ances. Procedures are described for measuring pro- tein in solution or after precipitation wit,h acids or other agents, and for the determination of as little as 0.2 y of protein.
Article
The metabolism of chlorogenic acid, naringin, and rutin, representative members of three common families of dietary polyphenols, the hydroxycinnamates, the flavanones, and the flavonols, respectively, was studied in an in vitro mixed culture model of the human colonic microflora. Time- and concentration-dependent degradation of all three compounds was observed, which was associated with the following metabolic events after cleavage of the ester or glycosidic bond: reduction of the aliphatic double bond of the resulting hydroxycinnamate caffeic acid residue; dehydroxylation and ring fission of the heterocyclic C-ring of the resulting deglycosylated flavanone, naringenin, and of the deglycosylated flavonol, quercetin (which differed depending on the substitution). The metabolic events, their sequences, and major phenolic end products, as identified by GC-MS or LC-MS/MS, were elucidated from the structural characteristics of the investigated compounds. The major phenolic end products identified were 3-(3-hydroxyphenyl)-propionic acid for chlorogenic acid, 3-(4-hydroxyphenyl)-propionic acid and 3-phenylpropionic acid for naringin, and 3-hydroxyphenylacetic acid and 3-(3-hydroxyphenyl)-propionic acid for rutin. The degree of degradation of the compounds studied was significantly influenced by the substrate concentration as well as individual variations in the composition of the fecal flora. The results support extensive metabolism of dietary polyphenols in the colon, depending on substrate concentration and residence time, with resultant formation of simple phenolics, which can be considered biomarkers of colonic metabolism if subsequently absorbed. It is also apparent that a relatively small number of phenolic degradation products are formed in the colon from the diverse group of natural polyphenols.
Report of tea technologist
  • S Ramaswamy
Ramaswamy, S., 1978. Report of tea technologist. UPASI Scientific Department of Annual Report, 126 – 148.
ISO, Methods for determination of substances characteristic of green and black tea. Part 2: Determination of catechins in green tea-method using high performance liquid chromatography
  • Anon
Anon. (1999). ISO, Methods for determination of substances character-istic of green and black tea. Part 2: Determination of catechins in green tea-method using high performance liquid chromatography. ISO/CD 14502-2.