Kombucha Fermentation Research Articles

Exploring the Acetobacteraceae family isolated from kombucha SCOBYs worldwide and comparing yield and characteristics of biocellulose under various fermentation conditions

Bacterial cellulose (BC) is a cellulosic biopolymer produced by specific acetic acid bacteria during kombucha fermentation. In this study, bacterial cellulose-producing strains were isolated from four different global kombucha SCOBY samples obtained from markets in the Netherlands, America, China, and Iran. The strains were identified using biochemical and molecular techniques. The ability of species to produce BC was evaluated under both static and stirred fermentation conditions. Seven dominant strains from the Acetobacteraceae family and the genus of Komagataeibacter and Gluconacetobacter were identified and submitted to NCBI gene bank archives: K. xylinus CH1, K. sucrofermentans IR2, K. intermedius IR3, K. cocois AM2, K. sucrofermentans NE4, K. cocois NE6, and G. liquefaciens NE7. Among these, K. intermedius IR3, isolated from local Iranian SCOBY, exhibited the highest BC production yield at 5.733 ± 0.170 gL−1 under static fermentation conditions. On the other hand, K. xylinus CH1, from Chinese SCOBY, had the highest yield under stirred conditions, producing 12.689 ± 0.808 gL−1 of BC. The BC production yield of both K. xylinus CH1 and K. intermedius IR3 under stirred conditions was 3 and 1.3 times more than static conditions, respectively. Despite the yield differences, static fermentation demonstrated superior physicochemical characteristics; such as moisture content, water holding capacity, and crystallinity degree, compared to stirred. Therefore, depending on the intended application in industry and specific criteria, both products could serve as functional substitutes in food and medicine sectors.

Dewatering and drying of Kombucha Bacterial Cellulose for preparation of biodegradable film for food packaging

Kombucha Bacterial Cellulose (KBC), obtained from waste products of kombucha fermentation, has potential applications in diverse fields. The present study used tea waste as a raw material for producing kombucha-like beverages and bacterial cellulose (BC). The in-situ dewatering and drying operations were performed to remove the high-water content from fermented KBC. Herein, the performance of BC in pressure-driven separation has been investigated as a function of dewatering pressure, drying temperature, and drying time in a multifunctional filtration cell. The Central Composite Design (CCD) was used to optimize the dewatering and drying parameters. The optimum conditions were found to be 4 bar pressure, 99 °C drying temperature, and 5 min drying time with a desirability value of 0.921. The predicted response values agreed with actual responses within 2.3–2.7 %. The dried films were prepared at optimized conditions and used to investigate thickness, density, mechanical properties, Fourier transform infrared, and scanning electron microscopy. The properties of KBC film varied as fermentation days increased. The KBC films' transparency decreased as thickness and density increased. The KBC film exhibits excellent mechanical properties such as tensile strength, maximum load, extension at the break, load at the break, and Young's modulus. The KBC films have been reported to be biodegradable and non-toxic and may be used for food packaging. Moreover, the present study successfully demonstrated that KBC packaging material could extend the shelf life of tomatoes by 13–15 days under accelerated conditions.

Enhanced Biological Potential and Phytochemical Profiling of Phoenix Dactylifera Leaves (Deglet Nour and Alig) by Kombucha Fermentation: Focus on Polyphenols, Antioxidant, Antidiabetic, and Cytotoxic Activities.

The date palm, scientifically known as Phoenix dactylifera, is an important cultural and economic source of wealth in southern Tunisia. It produces considerable agricultural waste, including palm leaves, the disposal of which is often a challenge. Our study addresses the sustainable conversion of date palm leaves into a valuable product through kombucha fermentation, focusing on two widely used varieties in Tunisia: Deglet Nour and Alig. HPLC-RI analysis showed a significant difference in the fermentation process between the treated samples, which is reflected in the highest sugar consumption and metabolite production in Alig palm. Unfermented and fermented date palm leaves were sequentially extracted with solvents of increasing polarity to evaluate their chemical composition and bioactivity. The results showed that kombucha fermentation significantly increased the total phenolic content, with the highest amounts in the ethyl acetate fraction. In terms of antioxidant activity, the ethyl acetate extracts showed a high percentage inhibitory activity (82.76%) against the DPPH radical found in fermented Palm Alig, which also exhibited the most important antidiabetic capacity (resulting in an IC50 value of 20 µg/mL). The chemical analyses resulted in the detection of 19 compounds by HPLC-DAD and 50 volatiles by GC-MS, which are mainly found in kombucha extracts.

Kombucha Fermentation in Coffee: Application of Constant Air Flow Reactor

Kombucha Fermentation in Coffee: Application of Constant Air Flow Reactor

Dynamic changes in microbial communities and volatile compounds in kombucha fermentation using Flos sophorae and Elm fruits, compared to black and green tea

The dynamic changes in physicochemical properties, microbial communities, and volatile compounds in kombucha made from Flos sophorae (FLSK) and Elm fruit (EFK) were compared to those of black tea (BTK) and green tea (GTK) over a 12-day fermentation period. The results revealed that overall flavonoid and polyphenol content, as well as antioxidant activity, increased initially and then decreased, accompanied by a steady reduction in pH within the fermentation broths investigated. Notably, the GTK exhibited stronger antioxidant activity than the other fermentation broths. Furthermore, 16S rRNA gene sequencing revealed that Komagataeibacter rhaeticus, Komagataeibacter saccharivorans, and Acidovorax wautersii were the dominating microbial species in the fermentation broths under this study. Komagataeibacter rhaeticus initially reduced and then increased throughout the FLSK fermentation, whereas Komagataeibacter saccharivorans increased from day 0 to day 6, and remain stable by day 12 during the EFK fermentation. Comparative analysis revealed that Komagataeibacter rhaeticus was more abundant in the FLSK and GTK than in the EFK and BTK, whereas Komagataeibacter saccharivorans showed a higher abundance in the EFK relative to the other fermentation broths. Gas chromatography-mass spectrometry identified acetic acid, linalool, ethanol, and ethyl acetate as the major volatile chemicals that rose significantly in fermentation mixtures of the examined substrates. The FLSK had a much higher linalool concentration than the other fermentation broths, although the EFK and GTK had higher ethanol content. Correlation study found that Komagataeibacter rhaeticus was negatively related with alcohol compounds, but Komagataeibacter saccharivorans was positively associated with a diverse spectrum of acids, alcohols, and esters. The study found changes in bioactive chemicals as well as interactions between bacterial populations and volatile compounds throughout fermentation in the substrates investigated.

Application of scoby bacterial cellulose as hydrocolloids on physicochemical, textural and sensory characteristics of mango jam.

The scoby pellicle of symbiotic culture of bacteria and yeast is a by-product from kombucha fermentation. While a portion is used as starter culture, the remainder is often discarded, yet it can be a valuable source of bacterial cellulose. Scoby from black, green and oolong tea kombucha fermentation was assessed for its hydrocolloid effects in mango jam-making through evaluation of physicochemical, textural and sensory characteristics. Quality of jam was significantly improved with water activity reduction up to 22.22% to 0.679, moisture content reduction up to 37.06% to 19.92%, and a pH drop up to 5.9% to 3.19 with the use of 20 to 100 g kg-1 scoby. In colour analysis, presence of scoby led to a brighter jam due to higher values from 30.98 to a range of 31.82 to 40.83. Texture of jam with scoby gave higher gel strength and adhesiveness, with the most prominent effects from the black tea kombucha. Overall acceptability in sensory test scoring was above 70% on a nine-point hedonic scale with the 40 g kg-1 green tea kombucha scoby jam chosen as the most preferred. Scoby gave significant contributions to jam stability, appearance and texture, showing potential as a clean-label food ingredient. © 2024 Society of Chemical Industry.

A rapid method for detecting l-Theanine during kombucha fermentation using SERS combined with machine/deep learning

The rapid detection of key indicators during the fermentation is crucial for improving product quality. In light of this, a strategy was developed for the rapid detection of l-Theanine during kombucha fermentation using surface-enhanced Raman Scattering (SERS) coupled with machine/deep learning methodologies. After analyzing the attribution of l-Theanine SERS characteristic peaks, effective variable features, converted features, and depth features were extracted, and calibration models were constructed employing Partial Least Squares (PLS), Support Vector Machine (SVM), and a one-dimensional Convolutional Neural Network (1DCNN). Based on the first 10 principal components derived via principal component analysis (PCA), the established model, PCA10-1DCNN, displayed superior performance with a determination coefficient (Rp2) of 0.9750. PCA10-1DCNN achieved commendable verification efficacy, with a maximum error of 4.4460 µg/mL, indicating the efficacy of this strategy for the l-Theanine rapid detection. This study offers a viable strategy for the l-Theanine rapid detection in the production of tea-based beverages.

Cascara kombucha potential as a functional food for fasting glucose regulation, cholesterol control, and liver function modulation: in vitro and in vivo study

SummaryUnhealthy dietary patterns are a major contributor to obesity worldwide, leading to various adverse metabolic effects such as elevated liver enzyme levels and increased cholesterol concentrations. This study investigates the potential of cascara kombucha as a functional beverage to provide health benefits in both in vitro and in vivo models. Our results indicate that kombucha fermentation enhances the bioactive compounds in cascara, including polyphenols and flavonoids. The in vitro study found that cascara kombucha effectively decreased free radicals (DPPH and ABTS) levels, α‐amylase, and lipase activity, suggesting its potential to act as an antioxidant and modulate carbohydrate and lipid metabolism. In a mouse model, oral administration of cascara kombucha at a dose of 300 mg/kg body weight for 28 days successfully decreased fasting blood glucose levels, improved liver health by reducing aspartate transaminase and alanine transaminase levels, and lowered serum cholesterol content induced by a fat‐enriched diet compared to the untreated group. The levels of superoxide dismutase and catalase, suppressed by the fat‐enriched diet, were restored to normal. Additionally, cascara kombucha downregulated genes associated with inflammation induced by a fat‐enriched diet, including tnf‐α, IL‐6, IL‐1β, and cox‐2. It also positively affected the balance of intestinal microflora in mice by reducing coliform density and enhancing probiotic populations. These findings highlight the potential of cascara kombucha as a promising approach to addressing health issues caused by poor dietary habits and metabolic imbalances.

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.

Bioactive Hydrogel Formulation Based on Ferulic Acid-Grafted Nano-Chitosan and Bacterial Nanocellulose Enriched with Selenium Nanoparticles from Kombucha Fermentation.

Selenium nanoparticles (SeNPs) have specific properties that result from their biosynthesis particularities. Chitosan can prevent pathogenic biofilm development. A wide palette of bacterial nanocellulose (BNC) biological and physical-chemical properties are known. The aim of this study was to develop a hydrogel formulation (SeBNCSFa) based on ferulic acid-grafted chitosan and bacterial nanocellulose (BNC) enriched with SeNPs from Kombucha fermentation (SeNPsK), which could be used as an adjuvant for oral implant integration and other applications. The grafted chitosan and SeBNCSFa were characterized by biochemical and physical-chemical methods. The cell viability and proliferation of HGF-1 gingival fibroblasts were investigated, as well as their in vitro antioxidant activity. The inflammatory response was determined by enzyme-linked immunosorbent assay (ELISA) of the proinflammatory mediators (IL-6, TNF-α, and IL-1β) in cell culture medium. Likewise, the amount of nitric oxide released was measured by the Griess reaction. The antimicrobial activity was also investigated. The grafting degree with ferulic acid was approximately 1.780 ± 0.07% of the total chitosan monomeric units, assuming single-site grafting per monomer. Fourier-transform infrared spectroscopy evidenced a convolution of BNC and grafted chitosan spectra, and X-ray diffraction analysis highlighted an amorphous rearrangement of the diffraction patterns, suggesting multiple interactions. The hydrogel showed a high degree of cytocompatibility, and enhanced antioxidant, anti-inflammatory, and antimicrobial potentials.

Optimizing Oxygen Exposure during Kombucha Brewing Using Air-Permeable Silicone Bags

As the commercial and home brewing of kombucha expands to accommodate its increased popularity, novel brewing practices that generate non-alcoholic kombucha in an efficient manner become valuable. The research presented in this work compares kombucha brewed in a glass jar brewing vessel to that brewed in an air-permeable silicone bag. Identical kombucha ferments with various sugar food sources were prepared and placed in each vessel, and variables such as titratable acidity, pH, alcohol by volume, gluconic acid concentration, acetic acid concentration, and sugar content were studied as a function of time. The results indicated that, regardless of the food source, kombucha brewed in an air-permeable bag exhibited more efficient acid production, lower ethanol concentration, and greater sugar utilization relative to equivalent kombucha brewed in a jar.

Kombucha with yam: Comprehensive biochemical, microbiological, and sensory characteristics

Consumer demand for functional foods has increased, helping to popularize and increase the consumption of Kombucha. Other substrates have been used together with tea to improve the functional and sensory properties of the beverage. Thus, this study evaluated the comprehensive biochemical, microbiological, and sensory characteristics of kombuchas fermented with green tea (Camellia sinensis) and different concentrations of yam (0, 10, and 20 % w/v). Based on pre-tests to detect the best concentration of yam in the beverage (10, 20, 30, and 40 %) and fermentation time (5, 7, and 14 days),the concentrations of 10 and 20 % of yam and five days of fermentation were selected through pH, °Brix, and sensory analysis. During the kombucha fermentation, there was a decrease in °Brix and pH. Sucrose, glucose, fructose, citric, and succinic acids were related to the beginning of fermentation, and lactic and acetic acids were more related to the end of fermentation in the treatment containing 20 % yam. The fermentation time did not change the color of the kombucha. Fatty acids, phenols, terpenoids, and alcohols were the volatile groups with the most compounds identified. Only two yeast genera were identified (Brettanomyces bruxellensis and Pichia membranifaciens), and bacteria of the genera Acetobacter, Lactobacillus, Pantoea, Pseudomonas, Azospirillum, and Enterobacter. The beverage control showed less turbidity and more clear. The fruity descriptor was more perceived in treatments with yam. However, the perception of the apple descriptor decreases as the yam concentration increases. The yam’s concentration alters the kombucha’s microbiota and sensory characteristics, mainly appearance and acidity. Kombucha fermentation using yam extract is viable, and the product is sensorially accepted. However, technological improvements, such as yam flour, could be made mainly for appearance and taste attributes.

Definition of halal analysis of formulation of kombucha drink from simplicia of malay apple fruit (Syzygium malaccense)

The wealth of biodiversity and the abundance of native Indonesian germplasm resources have not been optimally utilized domestically. Malay apple, which belongs to the myrtaceae family, has various health benefits. However, its utilization is still limited, thus requiring ideas to increase public interest in this fruit. Therefore, innovation is carried out by transforming malay apple into kombucha fermentation beverages as a step to optimize its utilization. The research aimed to measure the total alcohol content, total acid, and total sugar in the formulation of kombucha beverages derived from malay apple fruit juice, with the goal of developing it into a functional beverage. The research process involved testing alcohol content using gas chromatography, measuring total acid by alkalimetric titration method, and measuring total sugar content by anthrone method. The research results showed that the malay apple kombucha sample the level of alcohol content was 0.0213%, the total acid was 1.38% (<2 g/L), and the total sugar was 0.807 µg. The kombucha malay apple which category halal kombucha.

Changes and biotransformation mechanism of main functional compounds during kombucha fermentation by the pure cultured tea fungus

Kombucha was fermented by the pure cultured tea fungus, and the changes of functional compounds and their transformation were explored. After fermentation, the contents of total polyphenols, total flavonoids, quercetin, kaempferol and catechins respectively enhanced by 77.14%, 69.23%, 89.11%, 70.32% and 45.77% compared with the control, while flavonol glycosides reduced by 38.98%. The bioavailability of polyphenols and flavonoids respectively increased by 29.52% and 740.6%, and DPPH and ABTS respectively increased by 43.81% and 35.08% compared with the control. Correlation analysis showed that microorganisms and the antioxidant activity were highly positive correlation with total polyphenols, total flavonoids, EGC, EC, EGCG, ECG, quercetin and kaempferol, and negative correlation with kaempferol-3-glucoside. The constructed models confirmed that organic acids were more likely to damage the structure of tea leaves, and enzymes (polygalacturonidase and tannase) and solvents (acids, alcohols and esters) had a synergistic effect on the biotransformation of functional compounds.

Efficiency of freeze- and spray-dried microbial preparation as active dried starter culture in kombucha fermentation.

Kombucha is a widely consumed fermented beverage produced by fermenting sweet tea with a symbiotic culture of bacteria and yeast (SCOBY). The dynamic nature of microbial communities in SCOBY may pose challenges to production scale-up due to unpredictable variations in microbial composition. Using identified starter strains is a novel strategy to control microorganism composition, thereby ensuring uniform fermentation quality across diverse batches. However, challenges persist in the cultivation and maintenance of these microbial strains. This study examined the potential of microencapsulated kombucha fermentation starter cultures, specifically Komagataeibacter saccharivorans, Levilactobacillus brevis and Saccharomyces cerevisiae, through spray-drying and freeze-drying. Maltodextrin and gum arabic-maltodextrin were employed as carrier agents. Our results revealed that both spray-dried and freeze-dried samples adhered to physicochemical criteria, with low moisture content (2.18-7.75%) and relatively high solubility (65.75-87.03%) which are appropriate for food application. Freeze-drying demonstrated greater effectiveness in preserving bacterial strain viability (88.30-90.21%) compared to spray drying (74.92-78.66%). Additionally, the freeze-dried starter strains demonstrated similar efficacy in facilitating kombucha fermentation, compared to the SCOBY group. The observations included pH reduction, acetic acid production, α-amylase inhibition and elevated total polyphenol and flavonoid content. Moreover, the biological activity, including antioxidant potential and in vitro tyrosinase inhibition activity, was enhanced in the same pattern. The freeze-dried strains exhibited consistent kombucha fermentation capabilities over a three-month preservation, regardless of storage temperature at 30 or 4 °C. These findings highlight the suitability of freeze-dried starter cultures for kombucha production, enable microbial composition control, mitigate contamination risks and ensure consistent product quality. © 2024 Society of Chemical Industry.

Physicochemical Characteristics of Bitter Leaf (Vernonia amygdalina Del.) Kombucha with Palm Sugar Addition

Functional drinks are processed drinks that contain food components that are beneficial for body health and have good sensory evaluation. Functional drinks can be used to prevent degenerative diseases such as diabetes mellitus. Kombucha is a functional drink fermented from tea and sugar using a kombucha starter or Symbiotic Culture of Bacteria and Yeast (SCOBY). Kombucha has functions as an antioxidant, antidiabetic, anticancer and antimicrobial. A variety of leaves that include phenols and bitter leaves with components that are beneficial to the body can be used to make kombucha. Palm sugar can be used as alternative sugar for kombucha fermentation because palm sugar has a low glycemic index of 35. This study aims to determine the effect of using palm sugar concentration on total dissolved solids, viscosity, pH value, total flavonoids, total phenols, and reducing sugar content. The research results show that the use of palm sugar can increase total dissolved solids, viscosity, pH value, total flavonoids, total phenols and reducing sugars. The best treatment is the use of 25% palm sugar with a total soluble solids value of 18.38˚Brix, viscosity of 1.37 cP, pH value of 3.43, total flavonoids of 0.275 mg QE/g sample, total phenols of 0.99 mg GAE/ml, and reducing sugar of 9.24%.

Modelling pH Dynamics, SCOBY Biomass Formation, and Acetic Acid Production of Kombucha Fermentation Using Black, Green, and Oolong Teas

Kombucha is a traditional, fermented beverage made with an essential biomaterial known as SCOBY (symbiotic culture of bacteria and yeast). Three different tea types, namely black, green, and oolong, were compared in kombucha fermentation in terms of pH dynamics, the formation of SCOBY biomass, and the production of acetic acid. The rational, exponential, and polynomial models described pH dynamics with good fit, R2 > 0.98. The formation of SCOBY biomass and the production of acetic acid were modelled using sigmoidal functions, with three-parameter logistic and Gompertz models and four-parameter Boltzmann and Richards models. The F-test indicated that the three-parameter models were statistically adequate; thus, the Gompertz model was modified to present the biological meaning of the parameters. The SCOBY biomass formation rates ranged from 7.323 to 9.980 g/L-day, and the acetic acid production rates ranged from 0.047 to 0.049% acid (wt/vol)/day, with the highest values from the non-conventional substrate, oolong tea. The correlations between pH and SCOBY biomass or acetic acid using polynomial models enable the prediction of product formation in kombucha processing.

Spectrofluorimetric Analysis of Riboflavin Content during Kombucha Fermentation.

Kombucha is a traditional beverage obtained by the microbial fermentation of tea using a symbiotic culture of bacteria and yeasts. In addition to several documented functional properties, such as anti-inflammatory activity and antioxidant activity, kombucha is often credited with high levels of vitamins, including riboflavin. To our knowledge, the vitamin B2 content in traditionally prepared kombucha has been determined in only two studies, in which the concentration measured by the HPLC technique ranged from 2.2 × 10-7 to 2.1 × 10-4 mol dm-3. These unexplained differences of three orders of magnitude in the vitamin B2 content prompted us to determine its concentration during the cultivation of kombucha under very similar conditions by spectrofluorimetry. The B2 concentrations during the 10-day fermentation of black tea ranged from 7.6 × 10-8 to 3.3 × 10-7 mol dm-3.

Viability and Diversity of the Microbial Cultures Available in Retail Kombucha Beverages in the USA.

Kombucha is a two-stage fermented sweetened tea beverage that uses yeast and lactic acid bacteria (LAB) to convert sugars into ethanol and lactate and acetic acid bacteria (AAB) to oxidize ethanol to acetate. Its popularity as a beverage grew from claims of health benefits derived from this vibrant microbial bioconversion. While recent studies have shed light on the diversity of cultures in Kombucha fermentation, there is limited information on the diversity, and especially viability, of cultures in retail beverages that advertise the presence of Kombucha and probiotic cultures. In this study, 12 Kombucha beverages produced by different manufacturers throughout the US were purchased and microbially characterized. Eight of the beverages contained viable Kombucha cultures, while 3 of the remaining 4 had viable Bacillus cultures as added probiotics. Amplicon profiling revealed that all contained Kombucha yeast and bacteria cells. The dominant yeasts detected were Lachancea cidri (10/12), Brettanomyces (9/12), Malassezia (6/12), and Saccharomyces (5/12). Dominant LAB included Liquorilactobacillus and Oenococcus oeni, and AAB were Komagataeibacter, Gluconobacter, and Acetobacter. One beverage had a significant amount of Zymomonas mobilis, an ethanol-producing bacterium from Agave cactus. While Kombucha beverages differ in the types and viability of cultures, all except one beverage contained detectable viable cells.

Chemical composition and bioactivity status of Pancratium maritimum (sea lily) subjected to kombucha fermentation

Chemical composition and bioactivity status of Pancratium maritimum (sea lily) subjected to kombucha fermentation