Kombucha Beverage from Green, Black and Rooibos Teas: A Comparative Study Looking at Microbiology, Chemistry and Antioxidant Activity

Time and temperature influence on physicochemical, microbiological, and sensory profiles of yerba mate kombucha

The present work aimed to evaluate the features of yerba mate kombucha during 7 days of fermentation at either 25 ºC or 30 ºC, monitoring physicochemical changes, sensory profile, and sensorial acceptance. The symbiotic microbial culture of active bacteria and yeasts (SCOBY) at the beginning and the end of the bioprocess was also identified. The yerba mate kombuchas fermented at 25 ºC for 5 days or 30 ºC for 4 days were suitable for consumption according to Brazilian standards. Acetic acid, ethanol, and chlorophyll contents were dependent on fermentation time and temperature, unlike the total phenolic content. The main yeast and bacterium in SCOBY were Brettanomyces bruxellensis and Komagataeibacter rhaeticus, respectively, which remained dominant when fermentation was conducted for up to 7 days at both temperatures. Fermentation of yerba mate infusion led to products characterized by sourness, vinegar bitter, and fermented flavors and aromas, making the acceptance of non-fermented Yerba mate preferable to fermented infusions.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-024-05951-z.

Techno-functional aspects of kombucha analogs formulated from mulberry coproducts

This study investigated the techno-functional conditions for producing fermented beverages using the kombucha artisanal consortium (kAC) while implementing sustainable strategies. According to the circular economy principles, the study focused on mulberry coproducts (MC) generated as agro-industrial waste during mulberry fruit production. The presence of target microorganisms in the beverage and biofilm was recorded to determine the MC content necessary for establishing kAC. Additionally, the physicochemical characteristics, carbohydrate and polyphenol profiles were analyzed to understand their impact on antioxidant activity and sensory responses in the soft drink. Notably, a concentration of 0.25% MC was found to yield fermented soft drinks rich in probiotic populations and displaying nutraceutical qualities that enhance antioxidant activity and sensory acceptability. This study offers valuable technical guidance for repurposing mulberry pruning coproducts in the creation of novel products.

The potential of dried Ginkgo Biloba leaves as a novel ingredient in fermented beverages of enhanced flavour and antioxidant properties

Fermentation enhances the nutritional profile of foods and beverages like beer, wine, and fermented teas. Ginkgo biloba, long utilized for its health-enhancing properties, contains bioactive compounds like terpene trilactones and flavonoids, known for their antioxidant and neuroprotective effects. This study explores the feasibility of using dried Ginkgo biloba leaves in SCOBY-mediated fermentation to produce novel health-promoting beverages similar to kombucha. Infusions of dried Ginkgo biloba leaves with varying sugar concentrations are fermented over 21 days. Results showed that these beverages exhibited potent antioxidant properties, notably higher than tea-kombucha, attributed to increased polyphenol content. HPLC analysis identified significant levels of bioactive compounds such as catechin and apigenin. Sensory evaluation highlighted optimal acceptance of the seven-day fermented product. This research underscores the potential of Ginkgo biloba as a functional ingredient in fermented beverages, offering a healthier alternative to conventional soft drinks.

Multidisciplinary advances in kombucha fermentation, health efficacy, and market evolution

Kombucha, a fermented tea beverage, has seen a significant rise in global popularity. This increase is attributed to its reported health benefits and extensive cultural heritage. The comprehensive review examines kombucha through microbiology, biochemistry, and health sciences, highlighting its therapeutic potential and commercial viability. Central to kombucha production is the symbiotic culture of bacteria and yeasts (SCOBY), which regulates a complex fermentation process, resulting in a bioactive-rich elixir. The study examines the microbial dynamics of SCOBY, emphasizing the roles of various microorganisms. It focuses the contributions of acetic acid bacteria, lactic acid bacteria, and osmophilic yeasts, including genera such as Saccharomyces, Schizosaccharomyces, Zygosaccharomyces, Brettanomyces/Dekkera, and Pichia. These microorganisms play crucial roles in producing bioactive compounds, including organic acids, polyphenols, and vitamins. These bioactive compounds confer therapeutic properties to kombucha. These properties include antioxidant, antimicrobial, anti-inflammatory, antidiabetic, antihypertensive, cancer prevention, hepatoprotective, and detoxifying effects. The review also explores the growing market for kombucha, driven by consumer demand for functional beverages and opportunities for innovative product development. It emphasizes the necessity of standardized production to ensure safety and validate health claims. Identifying research gaps, the review highlights the importance of clinical trials to verify therapeutic benefits. Ultimately, this study integrates traditional knowledge with scientific research, providing directions for future studies and commercial expansion, emphasizing the role of kombucha in health and wellness.

Microbiological characterization of kombucha and biocellulose film produced with black tea and cocoa bean shell infusion

The food industry is increasingly striving to produce probiotics-based food and beverages using sustainable processes. Therefore, the use of by-products in product development has been investigated by several authors. The aim of this work was to investigate the effects of cocoa bean shell infusion in the production of kombucha through microbiological and genetic characterization. Three beverage formulations were prepared, one based on black tea (KBT), one based on cocoa bean shell infusion (KCS) and one containing 50 % black tea and 50 % cocoa shell infusion (KBL). The infusions were prepared with water, filtered, and sucrose was added. They were then homogenized and a portion of finished kombucha and SCOBY (symbiotic culture of bacteria and yeast) were added. Fermentation took place for 13 days and aliquots were collected every three days for physicochemical and microbial count analyses. Samples from the last day of fermentation were sent for DNA sequencing, extraction and quantification. The results were subjected to analysis of variance and compared by using Tukey's test (p < 0.05). The results show that there was a significant decrease in pH over time in all samples, while the titratable acidity increased, indicating an acidification of the beverage due to the production of organic acids. There was an increase in lactic acid bacterial colonies in all the formulations, which have a probiotic nature and are not always found in this type of beverage. Regarding the taxonomic classification of the samples, microorganisms of the kingdoms Fungi and Bacteria, of the families Saccharomycetaceae and Acetobacteraceae, were found in KBT, KCS and KBL, but with different microbiological compositions, with different amounts of yeasts and bacteria. Therefore, the use of by-products such as cocoa bean shell in the production of kombucha can contribute to the reduction of waste in the food industry and, at the same time, accelerate fermentation increasing the presence of lactic acid bacteria when compared to black tea.

Innovative Analogs of Unpasteurized Kombucha Beverages: Comparative Analysis of Mint/Nettle Kombuchas, Considering Their Health-Promoting Effect, Polyphenolic Compounds and Chemical Composition

Increasing demand for functional beverages is attracting consumers' attention and driving research to expand our knowledge of fermentation using symbiotic culture of bacteria and yeast (SCOBY) and demonstrate the health effects of consuming kombucha. The objective of this study was to develop innovative recipes for unpasteurized mint/nettle kombucha analogs, and to compare the products obtained under varying conditions in terms of chemical composition, bioactive polyphenols and health-promoting activity. Four variants of kombucha beverages (K1-K4), differing in the addition of sucrose and fermentation temperature, were formulated. The fermentation process provided data indicating the increase of antidiabetic, anti-inflammatory and anticholinergic properties, while a decrease in antioxidant capacity was observed. The content of polyphenolics was the highest on the seventh day of fermentation. A higher fermentation temperature and a larger amount of sucrose accelerated the fermentation process, which may be crucial for shortening the production time of kombucha drinks.

Microbiological, Functional, and Chemico-Physical Characterization of Artisanal Kombucha: An Interesting Reservoir of Microbial Diversity

Kombucha is a trending tea fermented via a complex microflora of yeasts and acetic acid bacteria. It can be a valid low-calorie substitute for soft drinks due to its sour, naturally carbonated, and sweet taste. Despite increased interest, the microflora and functional properties of kombucha have not yet been fully understood. The aim of this work was to characterize, from a microbiological, chemico-physical, and functional point of view, three types of artisanal kombucha obtained by fermenting green tea containing sugar by means of different starter cultures. Metagenomic analysis revealed a predominance of yeasts compared to bacteria, regardless of the sample. In particular, Brettanomyces spp. was found to be the dominant yeast. Moreover, the different types of kombucha had different microbial patterns in terms of acetic acid bacteria and yeasts. Ethanol and acetic acid were the dominant volatile molecules of the kombucha volatilome; the samples differed from each other in terms of their content of alcohols, esters, and acids. All the samples showed a high antioxidant potential linked to the high content of phenols. This study confirmed the positive chemico-physical and functional properties of kombucha and indicated that the microflora responsible for the fermentation process can significantly affect the characteristics of the final product.

Alternative Substrates for the Development of Fermented Beverages Analogous to Kombucha: An Integrative Review

Kombucha is a fermented beverage that originated in China and is spread worldwide today. The infusion of Camellia sinensis leaves is mandatory as the substrate to produce kombucha but alternative plant infusions are expected to increase the opportunities to develop new fermented food products analogous to kombucha, with high technological potential and functional properties. This review gathers information regarding promising alternative substrates to produce kombucha-analogous beverages, focusing on plants available in the Amazonia biome. The data from the literature showed a wide range of alternative substrates in increasing expansion, with 37 new substrates being highlighted, of which ~29% are available in the Amazon region. Regarding the technological production of kombucha-analogous beverages, the following were the most frequent conditions: sucrose was the most used carbon/energy source; the infusions were mostly prepared at 90-100 °C, which allowed increased contents of phenolic compounds in the product; and 14 day-fermentation at 25-28 °C was typical. Furthermore, herbs with promising bioactive compound compositions and high antioxidant and antimicrobial properties are usually preferred. This review also brings up gaps in the literature, such as the lack of consistent information about chemical composition, sensory aspects, biological properties, and market strategies for fermented beverages analogous to kombucha produced with alternative substrates. Therefore, investigations aiming to overcome these gaps may stimulate the upscale of these beverages in reaching wide access to contribute to the modern consumers' quality of life.

Additional advances related to the health benefits associated with kombucha consumption

Kombucha is a fermented, acidic beverage that dates back thousands of years as a remedy for various health problems in East Asia. Due to its health benefits, kombucha has gained popularity and attracted the attention of both consumers and researchers. The health benefits of kombucha are predominantly attributed to its bioactive compounds that have antioxidant, antimicrobial, probiotic, and other positive effects owing to fermentation. Many factors such as the type of the substrate used, the symbiotic culture of the bacterial yeast composition, and fermentation conditions influence the extent of these properties. This review focuses on recent developments regarding the bioactive constituents of kombucha and its potential health benefits (antimicrobial, antioxidant, antidiabetic, hepatoprotective effects) as well as its impact on multiple sclerosis, nephrotoxicity, gastric ulceration and gut microbiota. Additionally, the composition of kombucha, alternative uses of its biofilm, and potential toxicity are also discussed. Kombucha is a healthy and safe beverage with multiple health benefits that are primarily related to the presence of bacteria, yeasts, and other bioactive constituents. Moreover, kombucha has been suggested as a potential source of probiotics and eco-friendly materials (kombucha-derived bacterial cellulose) for several industries including food and textile.

Metagenomic, organoleptic profiling, and nutritional properties of fermented kombucha tea substituted with recycled substrates

Kombucha fermentation yields a diverse range of beneficial macro and micronutrients. In our study, we examined the metabolites, antioxidant activity, organoleptic characteristics, and nutritional attributes of traditionally prepared kombucha tea, using black tea and sugar (control) as substrates, and compared them with tea made from tea dust and blackstrap molasses (test). Kombucha tea crafted from functional raw materials exhibited enhanced sensory qualities and improved health-promoting properties. The levels of tannins, flavonoids, and phenols play a crucial role in determining the antioxidant activity of kombucha tea. Using the DPPH and FRAP methods, we investigated the antioxidant activity throughout the fermentation period, ranging from day 0 to day 12, under optimized conditions. The results consistently demonstrated an initial increase in antioxidant activity from day 0 to 6, followed by a decline from day 6 to 12. Notably, statistical analysis revealed that the antioxidant activity of the test sample was significantly better (p > 0.001) compared to the control sample. The nutritional content of the kombucha from day 6 of the test sample is higher than the control sample provided sugars (fructose 0.4 ± 0.1, glucose 0.7 ± 0.1, sucrose 1.4 ± 0.1) g/100 mL, minerals (calcium, 19.4 ± 0.15, iron 23.1 ± 0.25, and potassium 28.3 ± 0.25) mg/100 mL, vitamins (B1 0.58 ± 0.01, B2 0.30 ± 0.02, B3 0.33 ± 0.02, B6 0.75 ± 0.02, B9 0.19 ± 0.03, B12 0.9 ± 0.03, and C 1.38 ± 0.06) mg/100 mL, sodium 4.35 ± 0.25 mg/100 mL, calories 14.85 ± 0.25 mg/100 mL, carbohydrates 3.135 ± 0.12, and acids (acetic acid 4.20 ± 0.02, glucuronic acid 1.78 ± 0.02) mg/100 mL on day 12. The predominant microbial species identified in both control and test samples included Komagataeibacter rhaeticus, Gluconobacter oxydans, Brettanomyces bruxellensis, and Zygosaccharomyces bailli, each with varying dominance levels. These microorganisms play essential roles in metabolizing sugars, generating acids, and contributing to the distinctive flavor profile of kombucha. Sensory evaluations of the control and test samples were analyzed, and the overall preference was 88% for the test sample with tea dust and molasses. The sensory characteristics of the test sample included a fruity smell (41%), fizzy texture (66%), bright color (47%), and a fruity taste (67%), with overall acceptability (56%) rating it as excellent. Our research contributes to a deeper understanding of the interplay between raw materials, microbial composition, and the resulting composition of bioactive compounds.

Comparison of Anti-Inflammatory and Antibacterial Properties of Raphanus sativus L. Leaf and Root Kombucha-Fermented Extracts

In the cosmetics industry, the extract from Raphanus sativus L. is fermented using specific starter cultures. These cosmetic ingredients act as preservatives and skin conditioners. Kombucha is traditionally made by fermenting sweetened tea using symbiotic cultures of bacteria and yeast and is used in cosmetic products. The aim of this study was to evaluate the cosmetic properties of radish leaf and root extract fermented with the SCOBY. Both unfermented water extracts and extracts after 7, 14, and 21 days of fermentation were evaluated. The analysis of secondary plant metabolites by UPLC-MS showed higher values for ferments than for extracts. A similar relationship was noted when examining the antioxidant properties using DPPH and ABTS radicals and the protective effect against H2O2-induced oxidative stress in fibroblasts and keratinocytes using the fluorogenic dye H2DCFDA. The results also showed no cytotoxicity to skin cells using Alamar Blue and Neutral Red tests. The ability of the samples to inhibit IL-1β and COX-2 activity in LPS-treated fibroblasts was also demonstrated using ELISA assays. The influence of extracts and ferments on bacterial strains involved in inflammatory processes of skin diseases was also assessed. Additionally, application tests were carried out, which showed a positive effect of extracts and ferments on TEWL and skin hydration using a TEWAmeter and corneometer probe. The results obtained depended on the concentration used and the fermentation time.

Microbiome-based precision nutrition: Prebiotics, probiotics and postbiotics

Microorganisms have been used in nutrition and medicine for thousands of years worldwide, long before humanity knew of their existence. It is now known that the gut microbiota plays a key role in regulating inflammatory, metabolic, immune and neurobiological processes. This text discusses the importance of microbiota-based precision nutrition in gut permeability, as well as the main advances and current limitations of traditional probiotics, new-generation probiotics, psychobiotic probiotics with an effect on emotional health, probiotic foods, prebiotics, and postbiotics such as short-chain fatty acids, neurotransmitters and vitamins. The aim is to provide a theoretical context built on current scientific evidence for the practical application of microbiota-based precision nutrition in specific health fields and in improving health, quality of life and physiological performance.

Utilization of the sugar fraction from Arabica coffee pulp as a carbon source for bacteria producing cellulose and cytotoxicity with human keratinocyte

Coffee pulp (CP), a by-product of coffee production, is an underutilized resource with significant potential value. CP contains monosaccharides that can serve as an ideal carbon source for bacterial cultivation, enabling the production of value-added components such as medical-grade cellulose. Herein, we extracted the sugar fraction from Arabica CP and used it as a supplement in a growing media of a bacteria cellulose (BC), Komagataeibacter nataicola. The BC was then characterized and tested for cytotoxicity. The CP sugar fraction yielded approximately 7% (w/w) and contained glucose at 4.52 mg/g extract and fructose at 7.34 mg/g extract. Supplementing the sugar fraction at different concentrations (0.1, 0.3, 0.5, 0.7, and 1 g/10 mL) in sterilized glucose yeast extract broth, the highest yield of cellulose (0.0020 g) occurred at 0.3 g/10 mL. It possessed similar physicochemical attributes to the BC using glucose, with some notable improvements in fine structure and arrangement of the functional groups. In cytotoxicity assessments on HaCaT keratinocyte cells, bacterial cellulose concentrations of 2-1000 µg/mL exhibited viability of ≥ 80%. However, higher concentrations were toxic. This research innovatively uses coffee pulp for bacterial cellulose, aligning with the principles of a bio-circular economy that focuses on sustainable biomass utilization.

Evaluation of the probiotic potential of yeast isolated from kombucha in New Zealand

The current study investigated the in vitro probiotic potential of yeast isolated from kombucha, a tea beverage fermented with a symbiotic culture of acetic acid bacteria and yeast. A total of 62 yeast strains were previously isolated from four different commercial kombucha samples sold in New Zealand. Fifteen representative isolates belonging to eight different species were evaluated for their growth under different conditions (temperature, low pH, concentrations of bile salts, and NaCl). Cell surface characteristics, functional and enzymatic activities of the selected strains were also studied in triplicate experiments. Results showed that six strains (Dekkera bruxellensis LBY1, Sachizosaccharomyces pombe LBY5, Hanseniaspora valbyensis DOY1, Brettanomyces anomalus DOY8, Pichia kudraivzevii GBY1, and Saccharomyces cerevisiae GBY2) were able to grow under low-acid conditions (at pH 2 and pH 3) and in the presence of bile salts. This suggests their potential to survive passage through the human gut. All 15 strains exhibited negative enzymatic activity reactions (haemolytic, gelatinase, phospholipase, and protease activities), and thus, they can be considered safe to consume. Notably, two of the fifteen strains (Pichia kudraivzevii GBY1 and Saccharomyces cerevisiae GBY2) exhibited desirable cell surface hydrophobicity (64.60-83.87%), auto-aggregation (>98%), co-aggregation, resistance to eight tested antibiotics (ampicillin, chloramphenicol, colistin sulphate, kanamycin, nalidixic acid, nitrofurantoin, streptomycin, and tetracycline), and high levels of antioxidant activities (>90%). Together, our data reveal the probiotic activities of two yeast strains GBY1 and GBY2 and their potential application in functional food production.

Unveiling chemical responses in the kombucha-based fermentation of black tea, banana flower, and grape juice: LC-ESIMS, GNPS, MS-DIAL, and MS-FINDER-assisted chemical characterization

The lack of studies evaluating the chemical responses of kombucha microorganisms when exposed to plants is notable in the literature. Therefore, this work investigates the chemical behaviour of 7-, 14- and 21 day-fermentation of kombucha derived from three extracts obtained from banana inflorescence, black tea, and grape juice. After the acquisition of UPLC-ESI-MS data, GNPS molecular networking, MS-Dial, and MS-Finder were used to chemically characterize the samples. The microbial chemical responses were enzymatic hydrolysis, oxidation, and biosynthesis. The biosynthesis was different among the kombucha samples. In fermented black tea, gallic and dihydrosinapic acids were found as hydrolysis products alongside a sugar-derived product namely 7-(α-D-glucopyranosyloxy)-2,3,4,5,6-pentahydroxyheptanoic acid. The sphingolipids, safingol and cedefingol alongside capryloyl glycine and palmitoyl proline were identified. In fermented grapes, sugar degradation and chemical transformation products were detected together with three cell membrane hopanoids characterized as hydroxybacteriohopanetetrol cyclitol ether, (Δ6 or Δ11)-hydroxybacteriohopanetetrol cyclitol ether, and methyl (Δ6 or Δ11)-hydroxybacteriohopanetetrol cyclitol. The fermented banana blossom showed the presence of methyl (Δ6 or Δ11)-hydroxybacteriohopanetetrol cyclitol together with sphingofungin B, sphinganine and other fatty acid derivatives. Parts of these samples were tested for their inhibition against α-glucosidase and their antioxidant effects. Except for the 14-day fermented extracts, other black tea extracts showed significant inhibition of α-glucosidase ranging from 42.5 to 42.8%. A 14-day fermented extract of the banana blossom infusion showed an inhibition of 29.1%, while grape samples were less active than acarbose. The 21-day fermented black tea extract showed moderate antioxidant properties on a DPPH-based model with an EC50 of 5.29 ± 0.10 μg mL-1, while the other extracts were weakly active (EC50 between 80.76 and 168.12 μg mL-1).

Elevated abundance of Komagataeibacter results in a lower pH in kombucha production; insights from microbiomic and chemical analyses

Kombucha consumption has grown rapidly worldwide in the last decade, with production at both small- and large scales. The complex fermentation process involves both bacterial and yeast species, but little is known regarding the progression of microbial development during production. We explored the microbial diversity of multiple batches across two kombucha types, i. e commercial scale versus laboratory-made (hereafter "home") kombucha brew using metabarcoding to characterize both fungal and bacterial communities. We found the microbial community of the commercial kombucha brew to be more complex than that of the home brew. Furthermore, PERMANOVA uncovered significant compositional differences between the bacterial (F = 2.68, R2 = 0.23, p = 00.001) and fungal (F = 3.18, R2 = 0.26, p = 00.006) communities between batches. For the home brew, both alpha and beta diversity analyses revealed no significant differences between all batches and replicates. When the microbial diversity of the home and commercial kombucha types were directly compared, the former had higher proportions of Ammoniphilus and Komagataeibacter. The commercial kombucha on the other hand were high in Anoxybacillus, Methylobacterium and Sphingomonas. For the fungal communities, the most dominant fungal genera detected in both kombucha types were similar. Linear model revealed significant correlations between some microorganisms and the sugars and organic acids assayed in this study. For example, rising glucose levels correlated with an increase in the relative abundance of Komagataeibacter (F = 7.115, Adj. R2 = 0.44, p = 00.0003). We believe these results contribute towards achieving a better control of the kombucha fermentation process and may assist in targeted product diversification.

Volatilome, Microbial, and Sensory Profiles of Coffee Leaf and Coffee Leaf-Toasted Maté Kombuchas

Kombucha is a fermented beverage traditionally made from the leaves of Camelia sinensis. The market has drastically expanded recently, and the beverage has become more elaborated with new, healthy food materials and flavors. Pruning and harvesting during coffee production may generate tons of coffee leaves that are discarded although they contain substantial amounts of bioactive compounds, including those found in maté tea and coffee seeds. This study characterized the changes in volatilome, microbial, and sensory profiles of pure and blended arabica coffee leaf tea kombuchas between 3-9 days of fermentation. Acceptance was also evaluated by consumers from Rio de Janeiro (n = 103). Kombuchas (K) were prepared using black tea kombucha starter (BTKS) (10%), sucrose (10%), a symbiotic culture of Bacteria and Yeasts (SCOBY) (2.5%), and a pure coffee leaf infusion (CL) or a 50:50 blend with toasted maté infusion (CL-TM) at 2.5%. The RATA test was chosen for sensory profile characterization. One hundred volatile organic compounds were identified when all infusions and kombucha samples were considered. The potential impact compounds identified in CL K and CL-TM K were: methyl salicylate, benzaldehyde, hexanal, nonanal, pentadecanal, phenylethyl-alcohol, cedrol, 3,5-octadien-2-one, β-damascenone, α-ionone, β-ionone, acetic acid, caproic acid, octanoic acid, nonanoic acid, decanoic acid, isovaleric acid, linalool, (S)-dihydroactinidiolide, isoamyl alcohol, ethyl hexanoate, and geranyl acetone. Aroma and flavor descriptors with higher intensities in CL K included fruity, peach, sweet, and herbal, while CL-TM K included additional toasted mate notes. The highest mean acceptance score was given to CL-TM K and CL K on day 3 (6.6 and 6.4, respectively, on a nine-point scale). Arabica coffee leaf can be a co-product with similar fingerprinting to maté and black tea, which can be explored for the elaboration of potentially healthy fermented beverages in food industries.

Preparation and characterization of bacterial cellulose synthesized by kombucha from vinegar residue

Bacterial cellulose (BC) has been widely applied in various fields due to its excellent physicochemical properties, but its high production cost remains a challenge. Herein, the present study aimed to utilize the hydrolysate of vinegar residue (VR) as the only medium to realize the cost-effective production of BC. The BC production was optimized by the single-factor test. The treatment of 6 % VR concentration with 3 % acid concentration at 100 °C for 1.5 h and 96 U/mL of cellulase for 4 h at 50 °C obtained a maximum reducing sugar concentration of about 32 g/L. Additionally, the VR hydrolysate treated with 3 % active carbon (AC) at 40 °C for 0.5 h achieved a total phenol removal ratio of 86 %. The yield of BC reached 2.1 g/L under the optimum conditions, which was twice compared to the standard medium. The produced BC was characterized by SEM, FT-IR, XRD, and TGA analyses, and the results indicated that the BC prepared by AC-treated VR hydrolysate had higher fiber density, higher crystallinity, and good thermal stability. Furthermore, the regenerated BC (RBC) fibers with a tensile stress of 400 MPa were prepared successfully using AmimCl solution as a solvent by dry-wet-spinning method. Overall, the VR waste could be used as an alternative carbon source for the sustainable production of BC, which could be further applied to RBC fibers preparation.

Fermentation, functional analysis, and biological activities of turmeric kombucha

BACKGROUND

Kombucha is a popular fermented drink with therapeutic benefits. The present study aimed to examine the fermentation of turmeric-infused kombucha and evaluate its biological activities and functional properties.

RESULTS

The study of pH dynamics during fermentation found that turmeric kombucha has a lower pH decrease than standard kombucha, with the lowest pH of 3.1 being observed in 0.1% turmeric kombucha and the maximum pH of 3.8 found in 1% turmeric kombucha. The research shows that the symbiotic consortia of bacteria and yeast alters during the fermentation process with turmeric. Gas chromatogrphy-mass spectrometry analysis revealed that turmeric kombucha is abundant in terpenes, ketones, alcohols, aldehydes, phenols and fatty acids, with higher levels of active ingredients than regular kombucha. The kombucha with 0.6% turmeric had the highest overall acceptance score (9.0) in sensory evaluation. The total phenolic content after fermentation was in the range 0.2-0.8 mg gallic acid equivalents mL-1 . Increasing turmeric concentrations increased the antioxidant, cytotoxic and antibacterial activity of kombucha analogs, with the highest antioxidant activity (89%) observed at 0.8% turmeric, and the maximum cytotoxicity (74%) and antibacterial activity (zones of inhibition of 17.7 and 15.9 mm against Staphylococcus aureus and Escherichia coli, respectively) observed at 1% turmeric.

CONCLUSION

The fermentation of kombucha infused with turmeric enhanced its biological activities, making it a healthier alternative to traditional kombucha and presenting new opportunities in the field of functional foods. Further investigations into the mechanisms underlying these effects and in vivo studies are warranted to fully comprehend the impact of turmeric kombucha consumption on human health. © 2023 Society of Chemical Industry.

Phenolic Compounds and Antioxidant Properties of Fermented Beetroot Juices Enriched with Different Additives

Fermented beetroot juice is a beverage obtained from the fermentation of beetroot, most commonly red beet (Beta vulgaris L. var. conditiva). Nowadays, this product is increasingly recognised as a functional food with potentially beneficial health properties. It has been suggested to have antioxidant, anti-inflammatory, anticancer, antihypertensive, immunomodulatory, and probiotic effects, among others. Moreover, with the increasing popularity of the drink, newer variants are appearing in the food market, obtained by modifying the traditional recipe, adding other raw materials, herbs, and spices. Therefore, the aim of this study was to evaluate and compare the antioxidant potential and phytochemical composition of the selected fermented beetroot juices in different flavour variants available in the Polish food market. The study material consisted of six fermented beetroot juices: traditional, with garlic, with horseradish, with acerola, without salt, and iodized. The obtained results showed that the addition of acerola, horseradish, garlic, salt, and iodine in the form of sodium iodide and potassium iodide influenced the composition and properties of fermented beetroot juice. The most promising product in terms of potentially beneficial health properties related to the prevention of free radical diseases was fermented beetroot juice without salt (FRAP-5663.40 µM Fe (II)/L, ABTS-96.613%, TPC-760.020 mg GAE/L, TFC-221.280 mg RE/L). Iodized fermented beetroot juice had the highest vitamin C content-51.859 mg/100 mL. However, all the products tested were characterised by a significant content of biologically active substances with antioxidant properties and showed a high antioxidant potential. Moreover, all the fermented beetroot juices were rated positively in terms of flavour intensity, sweetness, acidity, colour, and overall acceptability. They can, therefore, be a good source of antioxidants in the daily diet.

Fermented Tea as a Food with Functional Value-Its Microbiological Profile, Antioxidant Potential and Phytochemical Composition

Kombucha is a fermented tea drink produced by a symbiotic culture of bacteria and yeast, known as SCOBY. Its base has traditionally been black tea, which has been recognized for its health-promoting properties, particularly its antioxidant activity based on its high content of pol-yphenolic compounds. A number of previous studies have demonstrated the equally favourable biochemical and phytochemical composition of green tea. The aim of this study was to analyse and compare the basic biochemical composition, microbiological composition and antioxidant properties of black and green tea-based Kombucha. The green tea-based Kombucha showed a quantitatively more abundant microbial composition (Lactic Acid Bacteria, Acetobacter sp., Yeast), a higher reducing potential (FRAP-4326.58 Fe(II)µM/L) and a higher content of total polyphenols (23.84 mg GAE/100 mL, reducing sugars (3212.00 mg/100 mL) as well as free amino acids (849.00 mg GLY/mL). Kombucha made from black tea, on the other hand, showed a higher anti-oxidant potential (1.17 Trolox (mM) TEAC), neutralising the DPPH radical at 94.33% and ABTS at 97.74%. It also had a higher level of acetic acid (0.08 g/100 mL). Green tea kombucha had a higher scavenging capacity of 90.6% for superoxide radical (O2-) and 69.28% for hydroxyl radical (·OH) than black tea kombucha. In the present study, both kombucha drinks tested were shown to be source of potent antioxidants. In addition, green tea, as a kombucha base, has proven to be as beneficial a raw material that will provide full nutritional and health-promoting values as traditional kombucha.

Addition of Saccharomyces eubayanus to SCOBY fermentations modulates the chemical and volatile compound profiles in kombucha

Kombucha is a fermented beverage derived from a sweetened tea fermentation inoculated with a bacteria-yeast consortium referred to as Symbiotic Culture of Bacteria and Yeast (SCOBY). Different SCOBY cultures can impact the beverage's quality and make the whole process highly variable. Adding Saccharomyces yeast cultures to the fermentation process can avoid stalled fermentations, providing a reproducible beverage. Here, we explored using different Saccharomyces eubayanus strains together with SCOBY in the context of kombucha fermentation. Our results show that yeast x SCOBY co-cultures exhibited a robust fermentation profile, providing ethanol and acetic acid levels ranging from 0,18-1,81 %v/v and 0,35-1,15 g/L, respectively. The kombucha volatile compound profile of co-cultures was unique, where compounds such as Isopentyl acetate where only found in yeast x SCOBY fermentations. Metabarcoding revealed that the SCOBY composition was also dependent on the S. eubayanus genotype, where besides Saccharomyces, amplicon sequence variants belonging to Brettanomyces and Starmerella were detected. These differences concomitated global changes in transcript levels in S. eubayanus related to the metabolism of organic molecules used in kombucha fermentation. This study highlights the potential for exploring different S. eubayanus strains for kombucha fermentation, and the significant yeast genotype effect in the profile differentiation in this process.

Understanding the effect of fermentation time on physicochemical characteristics, sensory attributes, and volatile compounds in green tea kombucha

Kombuchas are a trend in the fermented beverage field and the effect of fermentation time on their characteristics is necessary to better understand the process, mainly concerning volatile compounds, which are scarce information in the current literature. Thus, the present work aimed to evaluate the features of green tea kombucha during fermentation, monitoring the changes in pH, acidity, turbidity, polyphenols, ethanol, acetic acid, volatile compounds, and sensory profile and acceptance up to 14 days of fermentation. Kombuchas' pH and acidity decreased through time as expected, but after 4 days of fermentation, the beverage exceeded the Brazilian legal limits of acidity (130 mEq/L) and produced more than 0.5% AVB, which labels the beverage as alcoholic. Total polyphenols and condensed tannins content enhanced until the seventh day of fermentation and remained constant. Fermentation highly impacted the aroma of the infusion with a high formation of volatile acids, such as alcohols, esters, and ketones. Aldehydes were degraded during the bioprocess. Sensory characterization of kombucha showed that fermentation of 4 days increased perceived turbidity; vinegar, citric fruit, acid, and alcoholic aroma; and produced the beverage with sour, bitter, and vinegar flavor. Thus, the fermentation time of kombuchas must be controlled as they rapidly change and impact on the physicochemical parameters and sensory profile of the beverage can be negative.

Optimising the Production Process of Bacterial Nanocellulose: Impact on Growth and Bioactive Compounds

Research background

Research into bacterial cellulose production has been growing rapidly in recent years, as it has a potential use in various applications, such as in the medical and food industries. Previous studies have focused on optimising the production process through various methods, such as using different carbon sources and manipulating environmental conditions. However, further research is still needed to optimise the production process and understand the underlying mechanisms of bacterial cellulose synthesis.

Experimental approach

We used Plackett-Burman and Box-Behnken experimental designs to analyse the effect of different factors on bacterial cellulose production. The fermentation kinetics of the optimised medium was analysed, and the produced cellulose was characterised. This approach was used because it allows the identification of significant factors influencing bacterial cellulose growth, the optimisation of the culture medium and the characterisation of the produced cellulose.

Results and conclusions

The results showed that higher sucrose concentrations, higher kombucha volume fractions and a smaller size of the symbiotic culture of bacteria and yeast were the most important factors for the improvement of bacterial cellulose production, while the other factors had no relevant influence. The optimised medium showed an increase in the concentrations of total phenolic compounds and total flavonoids as well as significant antioxidant activity. The produced pure bacterial cellulose had a high water absorption capacity as well as high crystallinity and thermal stability.

Novelty and scientific contribution

The study makes an important scientific contribution by optimising the culture medium to produce bacterial cellulose more productively and efficiently. The optimised medium can be used for the production of a kombucha-like beverage with a high content of bioactive compounds and for the production of bacterial cellulose with high crystallinity and thermal stability. Additionally, the study highlights the potential of bacterial cellulose as a highly water-absorbent material with applications in areas such as packaging and biomedical engineering.

Native bacterial cellulose films based on kombucha pellicle as a potential active food packaging

The production of kombucha involves the synthesis of a bacterial cellulose-based native film by a microbial consortium, typically regarded as a waste by-product in commercial kombucha manufacturing. In this study, films were successfully obtained using the microbial consortium of kombucha, combined with infusions of black tea, green tea, rosehip, coffee, and licorice. These films exhibited a flexible rubbery-like structure and demonstrated inherent biological activity. Comparative analysis revealed that the licorice-based films exhibited a regular and less porous structure, while the green and black tea-based films displayed a porous structure, resulting in higher water permeability and swelling. Remarkably, green tea-based films showcased notable antioxidant activity (DPPH: %74.22 ± 2.05, ABTS: %81.59 ± 2.39) and exhibited antimicrobial properties against E. coli, S. aureus, and B. cereus, owing to their high phenolic content (1.62 ± 0.04 μg GAE/g). The antimicrobial efficacy of green tea-based films surpassed that of the other films against pathogenic microorganisms. By enhancing their hydrophobic properties, these innovative films hold promising potential as cost-effective, active, and environmentally friendly materials for food packaging applications.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-023-05808-x.

Chronic Kombucha Beverage Consumption Attenuates Inflammatory Markers and Histopathology of Brain Tissue in Transnet Global Brain Ischemia in Rats

There is evidence that kombucha beverage (KB), a traditional fermented beverage, has a preventive effect on experimental brain ischemia. According to our previous studies, pre-treatment of KB attenuates brain edema and improves motor skills and oxidative stress in a rat model of global brain ischemia. This study was designed to evaluate the effects of the pre-treatment of KB, as a novel agent, on pro-inflammatory parameters and brain histopathology changes following global brain ischemia. Adult male Wistar rats were randomly divided into the sham, the control, and the groups treated with kombucha (KB1 and KB2 groups). KB at doses 1 and 2 mL/kg was prescribed two-week consecutive days before induction of global brain ischemia. Global brain ischemia was induced by blocking common carotid arteries for 60 min and the following reperfusion by 24 h. The serum and brain levels of tumor necrosis factor-α(TNF-α), IL-1β, histopathological change, and infarct volume are determined using the ELISA, hematoxylin and eosin (H&E), and 2,3,5-triphenyl tetrazolium chloride (TTC) staining, respectively. This study indicated that pre-treatment of KB significantly reduced infarct volume, the serum, and brain levels of TNF-α and IL-1β. The histopathological finding of the brain tissue confirmed a protective role for pre-treatment KB in the ischemic rats. Thus, the present study showed that the beneficial effects of KB pre-treatment on brain ischemic may be mediated by decreasing pro-inflammatory parameters.

Kombucha Fermentation of Olympus Mountain Tea (Sideritis scardica) Sweetened with Thyme Honey: Physicochemical Analysis and Evaluation of Functional Properties

This study implemented kombucha fermentation of Olympus Mountain tea (Sideritis scardica) sweetened with honey (OMTWH) in order to investigate the potential for producing a novel beverage with functional properties. The increase in the total count of bacteria and yeast suggests that the OMTWH acts as a viable substrate for supporting the proliferation of the microorganisms of the Kombucha symbiotic culture. The fermentation resulted in a reduction in pH and increased total titratable acidity. After fermentation, a statistically significant increase in the vitamins C, B1, B2, B6, B7, and B12 content was observed (p < 0.05). Total phenolics and antioxidant activity of the fermented beverage was significantly enhanced, as assessed by the method of Folin-Ciocalteu and ABTS assay, respectively. Results revealed that OMTWH had a potent inhibitory activity of α-amylase, α-glucosidase, acetylcholinesterase, and butyrylcholinesterase; OMTWH fermented with a kombucha consortium exhibited even higher inhibition. Hence, the process of kombucha fermentation can convert OMTWH into a novel beverage with enhanced functional properties.

Research progress on alternative kombucha substrate transformation and the resulting active components

Kombucha is a customary tea-based beverage that is produced through the process of fermenting a mixture of tea and sugar water with symbiotic culture of bacteria and yeast (SCOBY). Traditional kombucha has various beneficial effects and can improve immunity. The significant market share of Kombucha can be attributed to the growing consumer inclination towards healthy foods within the functional beverage industry. The research focus has recently expanded from the probiotics of traditional black tea kombucha to encompass other teas, Chinese herbs, plant materials, and alternative substrates. There is a lack of comprehensive literature reviews focusing on substance transformation, functional, active substances, and efficacy mechanisms of alternative kombucha substrates. This article aimed to bridge this gap by providing an in-depth review of the biological transformation pathways of kombucha metabolites and alternative substrates. The review offers valuable insights into kombucha research, including substance metabolism and transformation, efficacy, pharmacological mechanism, and the purification of active components, offering direction and focus for further studies in this field.

Sucrose Concentration and Fermentation Temperature Impact the Sensory Characteristics and Liking of Kombucha

Kombucha is a fermented tea beverage consumed for its probiotics and functional properties. It has a unique sensory profile driven by the properties of tea polyphenols and fermentation products, including organic acids. Fermentation temperature and sucrose content affect the fermentation process and the production of organic acids; yet less is known about their impacts on the sensory profile and consumer acceptance. Thus, we aimed to examine the impact of sucrose concentration and fermentation temperature on sensory attributes and liking. For this study, kombucha tea was fermented at three different concentrations of sucrose and fermented at two temperatures for 11 days. Fermentation was monitored by pH, brix, and titratable acidity, and consumers (n = 111) evaluated the kombucha for sensory attributes and overall liking. The fermentation temperature resulted in significant differences in titratable acidity, with higher temperatures producing more organic acids, resulting in higher astringency, and suppressed sweetness. The lower fermentation was reported as significantly more liked, with no difference in liking between the 7.5% and 10% sucrose kombucha samples. Fermentation temperature had the greatest impact on the sensory profile rather than sucrose concentration, which had a greater effect on the fermentation rate and production organic acids.

Volatile, Microbial, and Sensory Profiles and Consumer Acceptance of Coffee Cascara Kombuchas

Given the substantial world coffee production, tons of coffee fruit cascara rich in bioactive compounds are discarded annually. Using this by-product to produce potentially healthy and acceptable foods is a sustainable practice that aggregates value to coffee production and may help improve people's lives. This study aimed to elaborate kombuchas from coffee cascara tea, evaluate their microbial profile, and monitor the changes in the volatile profile during fermentation, together with sensory attributes and acceptance by consumers from Rio de Janeiro (n = 113). Arabica coffee cascaras from Brazil and Nicaragua were used to make infusions, to which black tea kombucha, a Symbiotic Culture of Bacteria and Yeasts (SCOBY), and sucrose were added. Fermentation of plain black tea kombucha was also monitored for comparison. The volatile profile was analyzed after 0, 3, 6, and 9 days of fermentation via headspace solid phase microextraction GC-MS. A total of 81 compounds were identified considering all beverages, 59 in coffee cascara kombuchas and 59 in the black tea kombucha, with 37 common compounds for both. An increase mainly in acids and esters occurred during fermentation. Despite the similarity to black tea kombucha, some aldehydes, esters, alcohols, and ketones in coffee cascara kombucha were not identified in black tea kombucha. Potential impact compounds in CC were linalool, decanal, nonanal, octanal, dodecanal, ethanol, 2-ethylhexanol, ethyl acetate, ethyl butyrate, ethyl acetate, β-damascenone, γ-nonalactone, linalool oxide, phenylethyl alcohol, geranyl acetone, phenylacetaldehyde, isoamyl alcohol, acetic acid, octanoic acid, isovaleric acid, ethyl isobutyrate, ethyl hexanoate, and limonene. The mean acceptance scores for cascara kombuchas varied between 5.7 ± 0.53 and 7.4 ± 0.53 on a nine-point hedonic scale, with coffee cascara from three-day Nicaragua kombucha showing the highest score, associated with sweetness and berry, honey, woody, and herbal aromas and flavors. The present results indicate that coffee cascara is a promising by-product for elaboration of fermented beverages, exhibiting exotic and singular fingerprinting that can be explored for applications in the food industry.

Development of Fermented Kombucha Tea Beverage Enriched with Inulin and B Vitamins

Kombucha is a sweet and sour beverage made by fermenting a liquid base with a symbiotic culture of bacteria and yeast. Different tea substrates, carbohydrate sources, and additional ingredients are used to create beverages with different physical and chemical characteristics. The purpose of this work was to create a recipe and technology to study the properties of the beverage based on kombucha with a given chemical composition. The content of added functional ingredients (vitamins and inulin) in quantities comparable with reference daily intake was the specified parameter characterizing the distinctive features of the enriched beverages. For fermentation using symbiotic cultures of bacteria and yeast, a black tea infusion sweetened with sucrose was used as a substrate. The changes in the physicochemical characteristics of the fermented tea beverage base were evaluated. The dynamics of changes in pH, acidity, the content of mono- and disaccharides, ethanol, organic acids, polyphenolic compounds, and volatile organic substances were shown. The fermentation conditions were selected (pH up to 3.3 ± 0.3, at T = 25 ± 1 °C, process duration of 14 days) to obtain the beverage base. Strawberry and lime leaves were used as flavor and aroma ingredients, and vitamins with inulin were used as functional ingredients. Since the use of additional ingredients changed the finished beverage’s organoleptic profile and increased its content of organic acids, the final product’s physical–chemical properties, antioxidant activity, and organoleptic indicators were assessed. The content of B vitamins in the beverages ranges from 29 to 44% of RDI, and 100% of RDI for inulin, which allows it to be attributed to the category of enriched products. The DPPH inhibitory activity of the beverages was 82.0 ± 7%, and the ethanol content did not exceed 0.43%. The beverages contained a variety of organic acids: lactic (43.80 ± 4.82 mg/100 mL), acetic (205.00 ± 16.40 mg/100 mL), tartaric (2.00 ± 0.14 mg/100 mL), citric (65.10 ± 5.86 mg/100 mL), and malic (45.50 ± 6.37 mg/100 mL). The technology was developed using pilot equipment to produce fermented kombucha tea enriched with inulin and B vitamins.

Fermented Beverage Benefits: A Comprehensive Review and Comparison of Kombucha and Kefir Microbiome

Beverage fermentation is an ancient ritual that has been practised for millennia. It was slowly disappearing from households and communities due to the advancement of manufacturing technology and the marketing of soft drinks until the recent revival of the beverage fermentation culture due to an increase in the demand for health drinks amid the COVID-19 pandemic. Kombucha and kefir are two well-known fermented beverages that are renowned for their myriad of health benefits. The starter materials for making these beverages contain micro-organisms that act like microscopic factories producing beneficial nutrients that have antimicrobial and anticancer effects. The materials modulate the gut microbiota and promote positive effects on the gastrointestinal tract. Due to wide variations in the substrates and types of micro-organisms involved in the production of both kombucha and kefir, this paper compiles a compendium of the micro-organisms present and highlights their nutritional roles.

Changes in the chemical compositions and biological properties of kombucha beverages made from black teas and pineapple peels and cores

Several raw materials have been used as partial supplements or entire replacements for the main ingredients of kombucha to improve the biological properties of the resulting kombucha beverage. This study used pineapple peels and cores (PPC), byproducts of pineapple processing, as alternative raw materials instead of sugar for kombucha production. Kombuchas were produced from fusions of black tea and PPC at different ratios, and their chemical profiles and biological properties, including antioxidant and antimicrobial activities, were determined and compared with the control kombucha without PPC supplementation. The results showed that PPC contained high amounts of beneficial substances, including sugars, polyphenols, organic acids, vitamins, and minerals. An analysis of the microbial community in a kombucha SCOBY (Symbiotic Cultures of Bacteria and Yeasts) using next-generation sequencing revealed that Acetobacter and Komagataeibacter were the most predominant acetic acid bacteria. Furthermore, Dekkera and Bacillus were also the prominent yeast and bacteria in the kombucha SCOBY. A comparative analysis was performed for kombucha products fermented using black tea and a fusion of black tea and PPC, and the results revealed that the kombucha made from the black tea and PPC infusion exhibited a higher total phenolic content and antioxidant activity than the control kombucha. The antimicrobial properties of the kombucha products made from black tea and the PPC infusion were also greater than those of the control. Several volatile compounds that contributed to the flavor, aroma, and beneficial health properties, such as esters, carboxylic acids, phenols, alcohols, aldehydes, and ketones, were detected in kombucha products made from a fusion of black tea and PPC. This study shows that PPC exhibits high potential as a supplement to the raw material infusion used with black tea for functional kombucha production.

Intracellular Antioxidant and Anti-Inflammatory Effects and Bioactive Profiles of Coffee Cascara and Black Tea Kombucha Beverages

Kombucha is a functional beverage obtained through fermentation of sweetened Camellia sinensis infusion by a symbiotic culture of bacteria and yeasts that exerts many beneficial biological effects, mostly related to its antioxidant and anti-inflammatory effects. Alternative raw materials have been used to create new kombucha or kombucha-like products. Coffee is the most important food commodity worldwide and generates large amounts of by-products during harvest and post-harvest processing. The main coffee by-product is the dried fruit skin and pulp, popularly known as cascara. To date, no studies have evaluated the potential bioactivity of coffee cascara kombucha. In this study, we aimed to measure and compare the effects of infusions and kombuchas made with arabica coffee cascaras (n = 2) and black tea leaves (n = 1), fermented for 0, 3, 6, and 9 days on the intracellular production of Reactive Oxygen Species (ROS) and Nitric Oxide (NO) in model cells. Oxidative stress was induced in HK-2 cells with indoxyl sulfate (IS) and high glucose (G). Inflammation was induced with lipopolysaccharide (LPS) in RAW 264.7 macrophage. The contents of phenolic compounds, caffeine, and other physicochemical parameters were evaluated. To the best of our knowledge, this is the first study providing information on the bioactive profile and on the potential biological effects of coffee cascara kombucha. Fermentation caused the release of bound phenolic compounds from the infusions, especially total chlorogenic acids, with an average increase from 5.4 to 10.7 mg/100 mL (98%) and 2.6-3.4 mg/100 mL (30%) in coffee cascara and black tea kombucha, respectively, up to day 9. All evaluated beverages reduced (p < 0.0001) similarly the intracellular ROS (41% reduction, on average) and uric acid (10-55%) concentrations in HK-2 model cells, reversing the induced oxidative stress. All beverages also reduced (p < 0.0001, 81-90%) NO formation in LPS-induced macrophages, exhibiting an anti-inflammatory effect. These potential health benefits may be mostly attributed to polyphenols and caffeine, whose contents were comparable in all beverages. Coffee cascara showed similar potential to C. sinensis to produce healthy beverages and support sustainable coffee production.

Kombucha Beverages Produced from Fruits, Vegetables, and Plants: A Review on Their Pharmacological Activities and Health Benefits

Kombucha is a traditional health beverage produced by fermenting sweetened tea with a symbiotic culture of bacteria and yeasts. Consumption of kombucha beverages has been growing and there is kombucha commercially available worldwide as one of the most famous low-alcohol beverages. Kombucha beverages have been claimed to have beneficial effects on human health because they contain a variety of bioactive compounds that possess various functional properties. At present, several kinds of raw material (e.g., milk, fruit, vegetables, and herbs) have been fermented with kombucha consortium and consumed as kombucha beverages. Although several studies have been written regarding the biological activities of kombucha and raw materials, there is however little information available on the characterization of their components as well as the biological activities of fermented kombucha from many raw material mixtures. Several pharmacological activities were reviewed in the scientific literature, describing their potential implications for human health. In addition, the adverse effects and toxicity of kombucha consumption were also reviewed. In this study, we focused on the main and latest studies of the pharmacological effects of kombucha beverages produced from various kinds of raw materials, including antioxidant, anti-inflammatory, immunomodulatory, antimicrobial, anticancer, antidiabetic, antihypertensive, and antihyperlipidemic effects in in vitro and in vivo studies.

Kombucha analogs from maqui juice: Consortium age and sugar concentration effects on anthocyanin stability and its relationship with antioxidant activity and digestive enzyme inhibition

The fermentation of maqui juice (MJ), by incorporating kombucha as a starter culture, produces beverages with variable and stable anthocyanin contents. The metabolic effect of kombucha starter cultures obtained at different fermentation times was explored on the anthocyanin stability of maqui (Aristotelia chilensis (Mol.) Stuntz) juice supplemented at different concentrations of sucrose and fermented at different times. The stability of anthocyanins was associated with the levels of catechin detected in the fermentation system. This study concludes that the fermentation of MJ with sucrose (10%) and kombucha consortium of 7-days old, promotes the release and accumulation of phenolic compounds that act as co-pigments, with the best response in quality parameters of beverages such as color intensity, tone, hyperchromic effect, and a significant bathochromic shift. Finally, the additive effect of phenolic constituents with stable anthocyanins, confers to kombucha analogs an outstanding antioxidant quality and inhibitory effects on key enzymes in digestive processes.

Characterization of Aroma Active Compound Production during Kombucha Fermentation: Towards the Control of Sensory Profiles

Since the sensorial profile is the cornerstone for the development of kombucha as a beverage with mass market appeal, advanced analytical tools are needed to gain a better understanding of the kinetics of aromatic compounds during the fermentation process to control the sensory profiles of the drink. The kinetics of volatile organic compounds (VOCs) was determined using stir bar sorptive extraction-gas chromatography-mass spectrometry, and odor-active compounds were considered to estimate consumer perception. A total of 87 VOCs were detected in kombucha during the fermentation stages. The synthesis of mainly phenethyl alcohol and isoamyl alcohol probably by Saccharomyces genus led to ester formation. Moreover, the terpene synthesis occurring at the beginning of fermentation (Δ-3-carene, α-phellandrene, γ-terpinene, m- and p-cymene) could be related to yeast activity as well. Principal component analysis identified classes that allowed the major variability explanation, which are carboxylic acids, alcohols, and terpenes. The aromatic analysis accounted for 17 aroma-active compounds. These changes in the evolution of VOCs led to flavor variations: from citrus-floral-sweet notes (geraniol and linalool domination), and fermentation brought intense citrus-herbal-lavender-bergamot notes (α-farnesene). Finally, sweet-floral-bready-honey notes dominated the kombucha flavor (2-phenylethanol). As this study allowed to estimate kombucha sensory profiles, an insight for the development of new drinks by controlling the fermentation process was suggested. Such a methodology should allow a better control and optimization of their sensory profile, which could in turn lead to greater consumer acceptance.

Silver Nanoparticles Loaded on Chitosan-g-PVA Hydrogel for the Wound-Healing Applications

Silver nanoparticle composites have abundant biomedical applications due to their unique antibacterial properties. In the current work, green tea leaf extract was used as a natural reducing agent to synthesize AgNPs (AgNPs) using microwave irradiation technology. Furthermore, microwave irradiation has been used for the preparation of AgNPs/chitosan (Ch) grafted polyvinyl alcohol (PVA) hydrogel samples. To approve the accomplishment of AgNPs hydrogel polymer, UV-spectrum, TEM, and FT-IR spectrum analyses and the release of silver ions, actions were taken. The wound-healing ability of the prepared hydrogel samples was measured via both the in vitro (fibroblast cells) and the in vivo using rat models. It was found that chitosan-grafted polyvinyl alcohol, including AgNPs, exhibited excellent antibacterial activity against E. coli and S. aureus using the agar diffusion method. It can be said that microwave irradiation was successful in creating a hydrogel that contained silver nanoparticles. A wound that was still open was successfully treated with these composites.

Chemical and Aromatic Changes during Fermentation of Kombucha Beverages Produced Using Strawberry Tree (Arbutus unedo) Fruits

The use of alternative ingredients in the production of kombucha has seen a recent increase. Our research aimed to characterize the chemical, nutritional, microbial, and aromatic profiles of kombucha beverages prepared with strawberry tree (Arbutus unedo) fruits fermented with three different SCOBYs for 21 days. The analyses showed similar levels of microbiological groups (aerobic mesophilic microorganisms, lactic acid bacteria, acetic acid bacteria, and yeasts)among the SCOBYs used. The beverages studied displayed a decrease in pH value and carbohydrate content, and protein degradation was also observed as fermentation progressed. However, the increase in total phenolic compounds during the first week proved to be a point of interest. A total of 20 volatile organic compounds were detected, giving different sensory qualities to the beverages: higher ethanol, benzaldehyde-4-ethyl, or acetic acid depending on the SCOBY used. The results obtained indicated that strawberry tree kombucha might be an alternative beverage with notable nutritional and aromatic properties, with fermentation time and SCOBY composition being identified as crucial factors.

Metagenomic and physicochemical analysis of Kombucha beverage produced from tea waste

Kombucha beverage produced through fermentation of sugared tea using bacteria and yeast has gained attention for its beneficial health benefits. However, the cost linked to the raw materials often increases the upstream process expenses, thereby the overall operating expenditures. Thus, there is a need to explore alternative waste and cost-effective raw materials for Kombucha fermentation. The present study, compared the physico-chemical and microbial growth pattern of Kombucha beverage production using tea waste from the tea processing industries with that of the green/black tea, reporting similar trends irrespective of its type. Further, the amplicon sequencing of 16S rRNA showed dominant presence of Komagataeibacter rhaeticus and high throughput sequencing of ITS1 confirmed the presence of yeast species similar to Brettanomyces bruxellensis in the tea waste based Kombucha beverage. Appreciable amount of carbohydrates (8.5/100 g) and energy (34 kcal/100 g) with appropriate organoleptic properties favourable for human consumption were also observed during the nutritional content and qualitative property assessment. The overall study showed a broad taxonomic and functional diversity existing during Kombucha fermentation process with tea waste to maintain a sustained eco-system to facilitate cost-effective beverage production with desired properties for safe consumption.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-022-05476-3.

Eco-physiological response of secondary metabolites of teas: Review of quality attributes of herbal tea

Herbal tea is a rich source of secondary metabolites which are reputed to have medicinal and nutritional efficacy. These secondary metabolites are influenced by the abiotic and biotic stresses that improve the production of herbal teas in terms of biomass production, accumulation and partitioning of assimilates of compounds. In this study, various examples of herbal teas have been shown to respond differently to secondary metabolites affected by environmental factors. Thus, the meta-analysis of this study confirms that different herbal teas' response to environmental factors depends on the type of species, cultivar, and the degree of shade that the plant is exposed. It is also evident that the metabolic processes are also known to optimize the production of secondary metabolites which can thus be achieved by manipulating agronomic practices on herbal teas. The different phenolic compound in herbal teas possesses the antioxidant, antimicrobial, antiatherosclerosis, anti-inflammatory, antimutagenic, antitumor, antidiabetic and antiviral activities that are important in managing chronic diseases associated with lifestyle. It can be precluded that more studies should be conducted to establish interactive responses of biotic and abiotic environmental factors on quality attributes of herbal teas.

Characterization of Lactic Acid Bacteria Isolated from Spontaneously Fermented Sausages: Bioprotective, Technological and Functional Properties

Fermentation is one of the most ancient strategies to improve safety and extend shelf-life of the products. Starter cultures are mainly represented by lactic acid bacteria (LAB), which may also be bioprotective agents controlling the fermentation process, the native microbiota and pathogen outgrowth. This work aimed to select new LAB strains from spontaneously fermented sausages produced in different areas of Italy, which can be effective as starter cultures and bioprotective agents in fermented salami. The strains, mainly belonging to the Latilactobacillus sakei species, were characterized for their ability to inhibit major meat pathogens, the presence of antibiotic resistances and amine production. Moreover, technological performances, such as growth and acidification kinetics at increasing NaCl concentrations, were studied. As a result, new autochthonous Lat. sakei strains were obtained, lacking antibiotic resistance, possessing antimicrobial activity against Clostridium sporogenes, Listeria monocytogenes, Salmonella and Escherichia coli and with high growth performance under osmotic pressure. These strains have the potential for future application to improve the safety of fermented meats, even under conditions in which chemical preservatives are reduced or eliminated. Moreover, studies on autochthonous cultures are pivotal for guaranteeing specific characteristics of traditional products that represent an important cultural heritage.

A New Substrate and Nitrogen Source for Traditional Kombucha Beverage: Stevia rebaudiana Leaves

Recently, the use of different herbal products as carbon sources instead of black and green tea in the preparation of traditional kombucha has been investigated. In this study, functional kombucha was prepared by adding Stevia rebaudiana Bertoni leaves, which have special organoleptic properties, to kombucha medium, and some properties of the beverage were analyzed. Tea blends were determined as 100% green tea (control = C), 75% green tea (GT) + 25% Stevia (ST), 50% GT + 50% ST, and 100% ST. On the 15th day of fermentation, gluconic acid (43.12 ± 0.01 g/L) was detected as dominant organic acid in GT75 + ST25 samples compared to group C (p < 0.05). According to physicochemical parameters that determine the drinkability properties of prepared teas, the best results were in GT25 + ST75 compared to group C (p < 0.05). It proved that the highest activity was in GT25 + ST75 on the 10th day in the groups that applied different antioxidant tests (DPPH, MCA, and CUPRAC). The antimicrobial activities of kombucha at 25, 50, 75, and 100% concentrations of GT and ST reached the highest levels in the GT25 + ST75 group in samples after 10 days of fermentation for all selected microorganisms. The results prove that GT25 + ST75 kombucha is a functional product with high drinkability on the 10th day of fermentation and also more beneficial for health due to the phenolic compounds from both green tea and Stevia. Stevia rebaudiana leaves can be suggested that be used as a new substrate and nitrogen source for kombucha production.

Effect of Brown Algae and Lichen Extracts on the SCOBY Microbiome and Kombucha Properties

Kombucha tea was made by the fermentation of SCOBY culture of green tea broth with the addition of Fucus vesiculosus algae extract, Cetraria islandica lichen extract and their mixture. Kombucha was also made without the herbal supplements as a control. After 11 days of fermentation, in addition to the yeast Brettanomyces bruxellensis and the bacteria Komagataeibacter rhaeticus and Komagataeibacter hansenii contained in all of the samples, the yeast Zygosaccharomyces bailii and bacteria Komagataeibacter cocois were detected in the samples with the herbal extracts. In all of the kombucha with herbal additives, the total fraction of yeast was decreased as compared to the control. The total content of polyphenols and the antioxidant activity of the beverages with and without the addition of herbal extracts were comparable. The kombucha made with the algae extract showed an increased content of sucrose and organic acids, while the fructose and glucose content in the samples with algae and the mixture of extracts were lower than in the other samples. The samples with the algae extract had the highest organoleptic indicators "aroma", "clarity" and "acidity", while the control samples had slightly higher indicators of "taste" and "aftertaste". The results of this study indicate the potential of algae and lichens as functional supplements for obtaining non-alcoholic fermented beverages with additional nutraceutical value.

Kombuchas from Green and Black Tea Modulate the Gut Microbiota and Improve the Intestinal Health of Wistar Rats Fed a High-Fat High-Fructose Diet

The Western diet can negatively affect the gut microbiota and is associated with metabolic disorders. Kombucha, a tea fermented by a symbiotic culture of bacteria and yeast (SCOBY), is known for its bioactive properties and has become popular in the last years. In this study, we evaluated the effects of regular kombucha consumption on the gut microbiota and on outcomes related to the intestinal health of Wistar rats fed a high-fat high-fructose diet. After eight weeks receiving a standard diet (AIN-93M) (n = 10) or a high-fat and high-fructose diet (HFHF) (n = 30) to induce metabolic disorders, the animals were subdivided into four groups: AIN-93M (n = 10); HFHF (n = 10); GTK (HFHF + green tea kombucha (n = 10); and BTK (HFHF + black tea kombucha; n = 10) for 10 weeks. Although body composition did not differ among the groups, the HFHF diet was associated with metabolic alterations, and stimulated the growth of gram-negative bacteria such as Proteobacteria and Bacteroides. Kombucha ingestion could somewhat modulate the gut microbiota, attenuating the effects of a Western diet by increasing propionate production and favoring the growth of beneficial bacteria, such as Adlercreutzia in the GTK group. Our results suggest that regular kombucha consumption may be beneficial to intestinal health, which can be mostly attributed to its high content and diversity of phenolic compounds.

Effects of Fermentation Time and Type of Tea on the Content of Micronutrients in Kombucha Fermented Tea

The fermented tea beverage Kombucha is obtained through a series of biochemical and enzymatic reactions carried out by symbiotic cultures of bacteria and yeasts (SCOBY). It contains organic acids, vitamins, amino acids, and biologically active compounds, notably polyphenols, derived mainly from tea. Kombucha exhibits a range of health-promoting properties, including antioxidant or detoxifying effects. This fermented beverage is traditionally brewed with black tea, but other types of tea are used increasingly, which may have significant implications in terms of chemical composition and health-promoting effects. In this preliminary study, we investigated the content of micronutrients (manganese (Mn), copper (Cu), iron (Fe), chromium (Cr) and zinc (Zn)) by the ICP-OES method in Kombucha prepared with black, red, green and white tea at different time points of fermentation (1, 7, 14 days). It should be noted that the composition of separate ingredients such as tea, leaven or sugar has not been studied. Kombucha had the highest content of zinc-0.36 mg/L to 2.08 mg/L, which accounts for between 3% and 26% of the RDA (Recommended Dietary Allowance) for adults, and the smallest amounts of chromium (0.03 mg/L to 0.09 mg/L), which however represents as much as between 75% and 232% of the RDA. It has been demonstrated that the type of tea as well as the day of fermentation have a significant effect on the concentrations of selected minerals. Kombucha can therefore supplement micronutrients in the human diet.

Kombucha: Production and Microbiological Research

Kombucha is a sparkling sugared tea commonly prepared using a sugared tea infusion and fermented at ambient temperature for several days using a cellulose pellicle also called tea fungus that is comprised of acetic acid bacteria and yeast. Consumption of Kombucha has been reported as early as 220 B.C. with various reported potential health benefits and appealing sensory properties. During Kombucha fermentation, sucrose is hydrolysed by yeast cells into fructose and glucose, which are then metabolised to ethanol. The ethanol is then oxidised by acetic acid bacteria (AAB) to produce acetic acid which is responsible for the reduction of the pH and also contributes to the sour taste of Kombucha. Characterisation of the AAB and yeast in the Kombucha starter culture can provide a better understanding of the fermentation process. This knowledge can potentially aid in the production of higher quality products as these microorganisms affect the production of metabolites such as organic acids which are associated with potential health benefits, as well as sensory properties. This review presents recent advances in the isolation, enumeration, biochemical characteristics, conventional phenotypic identification system, and modern genetic identification techniques of AAB and yeast present in Kombucha to gain a better understanding of the microbial diversity of the beverage.

Medusomyces gisevii: cultivation, composition, and application

Tea fungus (Medusomyces gisevii) is a natural symbiotic consortium of yeast-like fungi and bacteria. Scientific literature provides a lot of information about the consortium, but it is largely fragmentary. We aimed to review and systematize the information on the research topic. We studied scientific publications, conference proceedings, intellectual property, regulatory documents, and Internet resources on the M. gisevii consortium using Scopus, Web of Science, e.LIBRARY.RU, and Google Academy. The methods applied included registration, grouping, classification, comparative analysis, and generalization. We described the origin and composition of tea fungus, specifying the microorganisms that make up its symbiotic community depending on the place of origin. Then, we reviewed the stages of fermentation and cultivation conditions in various nutrient media and presented the composition of the culture liquid. Finally, we analyzed the antimicrobial effect of M. gisevii on a number of microorganisms and delineated some practical uses of the fungus. The data presented in this article can be used to analyze or develop new methods for the cultivation and application of M. gisevii. We specified some possibilities for using not only the culture liquid but also the fruit body of the fungus in various industries.