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

Preparation, Quality Analysis and Antioxidant Activity of Sea Buckthorn (Hippophae rhamnoides L.) Kombucha Beverage at Different Fermentation Temperatures

Sea buckthorn is a unique resource with high nutritional value. The objective of this study was to develop a novel kombucha beverage from sea buckthorn juice by means of inoculation with kombucha (Symbiotic Culture of Bacteria and Yeast, SCOBY). The study investigated and compared the differences in physicochemical properties, antioxidant activity, and sensory evaluation during fermentation at different temperatures with those of traditional cultured green tea kombucha. The findings demonstrated that there were significant variations in physicochemical properties, antioxidant activity, and sensory evaluation among the sea buckthorn kombuchas produced at different temperatures. Among these, the sea buckthorn kombucha produced by fermentation at 28 °C exhibited the strongest antioxidant properties and the most favorable sensory evaluation. Furthermore, changes in the active substances were observed at different temperatures, and correlation analysis revealed that the antioxidant activity of Kombucha tea was correlated with the content of total phenols and total flavonoids. Consequently, the utilization of sea buckthorn juice in the production of kombucha beverages holds considerable promise.

As next-generation probiotics: acetic acid bacteria isolated from Kombucha beverages produced with Anatolian hawthorn leaves

This research examined acetic acid bacteria (AAB) isolated from Kombucha beverages produced with Anatolian hawthorn (Crataegus orientalis) as next-generation probiotics. Eighty-six AAB were isolated from the samples and investigated in terms of biosafety, viability in vitro gastrointestinal conditions, technological and bioactive properties, and also in vitro adhesion abilities. Seventy-six isolates demonstrating γ-hemolysis exhibited resistance to erythromycin and ampicillin. Besides, these isolates survived at low pH and in the presence of bile salts. However, the majority of AAB isolates showed tolerance to phenol, pepsin, and pancreatin. Also, twenty-one isolates showed protease enzyme activity, while eight isolates had amylase enzyme activity. Despite most of the isolates showed viability at 1.5% salt, only 19 isolates survived at 10% salt. Most AAB isolates exhibited inhibition zones ranging from 8 to 26 mm against test bacteria, their antioxidant activities were above 80%. Additionally, some isolates exhibited auto-aggregation ability ranging from 0.66 to 23.62% and co-aggregation ability ranging from 1.18 to 71.32%, while hydrophobicity ranged from 1.32 to 69.87% toward xylene. Finally, the indigenous 76 AAB isolates that had remarkable probiotic properties were characterized based on 16S rRNA gene sequencing, and the isolates belonged to Komagateibacter sp. (64.47%), Komagateibacter saccharivorans (15.79%), K. rhaeticus (11.84%), and Gluconobacter sp. (7.90%). As a result, the isolates identified as Gluconobacter sp. A21, Komagataeibacter sp. A139, Gluconobacter sp. A141, and Komagataeibacter sp. A146, which showed high viability under gastrointestinal conditions, safe and acceptable in terms of technological, bioactive, and adhesion properties and could be evaluated as next-generation probiotics.

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 (ethyl acetate and butanol) 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 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.

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.

Microorganisms and bacterial cellulose stability of Kombucha under different manufacture and storage conditions

It is crucial to clarify the stability of Kombucha in the manufacture and storage stages due to the extensive study on the fermented products of Kombucha and the increase in the use of bacterial cellulose (BC). This study aimed to evaluate the stability of Kombucha in different manufacturing and storage temperatures within a certain time period. The stability of microorganisms and BC in Kombucha was investigated through regular replacement with the tea media at 28 and 25°C for manufacture, and the storage temperature of Kombucha was at 25, 4, and -20°C. Morphological observations of the BC in Kombucha ended at 28 and 25°C for manufacture and storage were performed using atomic force microscopy (AFM) before inoculation. The viable cell counts and AFM results showed that the stability of Kombucha during manufacture was better at 28°C than at 25°C, with higher microbial viability and BC productivity in the former at the time of manufacture, whereas 25°C was more favorable for the stability of Kombucha during storage. At the same temperature of 25°C, the manufacturing practice improved the microbial viability and BC stability compared with storage; the pH value of Kombucha was lower, and the dry weight of BC was higher during storage compared with manufacture. The maximum BC water holding capacity (97.16%) was maintained by storage at 4°C on day 63, and the maximum BC swelling rate (56.92%) was observed after storage at -20°C on day 7. The research was conducted to provide reference information for applying Kombucha and its BC in food and development in other industries.

Evaluating Enterococcus faecium9 N-2 as a probiotic candidate from traditional village white cheese

In this study, various functional and probiotic attributes of the Enterococcus faecium 9 N-2 strain isolated from village-style white cheese were characterized, while also assessing its safety. To achieve this, we conducted an in vitro analysis of several key probiotic properties exhibited by the 9 N-2 strain. Notably, this strain demonstrated robust resilience to low pH, high bile salt concentrations, lysozyme, pepsin, pancreatin, and phenol. Furthermore, this strain displayed exceptional auto-aggregation capabilities and moderate co-aggregation tendencies when interacting with Escherichia coli. The cell-free supernatant derived from strain 9 N-2 exhibited significant antimicrobial activity against the tested pathogens. The strain exhibited resistance to gentamicin, meropenem, and bacitracin, while remaining susceptible to vancomycin and various other antibiotics. Furthermore, it was found that E. faecium 9 N-2 possessed the capacity to produce the phytase enzyme. When all the results of this study are evaluated, it is thought that 9 N-2 strain has superior probiotic properties, and therefore it can be used as probiotic in food, medicine, and animal feed in the future. In addition, further in vivo tests should be performed to fully understand its effects and mechanisms of action and to confirm its safety and probiotic effects. Further research and clinical trials are also needed to identify new strains with potential probiotic properties.

Kombucha: Challenges for Health and Mental Health

BACKGROUND

Increasing research into probiotics is showing potential benefits for health in general and mental health in particular. Kombucha is a recent beverage and can be considered a probiotic drink, but little is known about its effects on physical and mental health. This product is experiencing growth in the market; however, there are no scientific results to support its potential for physical and mental health.

AIM

This review article aims to draw attention to this issue and to highlight the lack of studies in this area.

KEY FINDINGS AND CONCLUSIONS

The lack of legislation for the correct marketing of this product may also constrain clinical studies. However, clinical studies are of utmost importance for an in-depth understanding of the effects of this product on the human body. More research is needed, not only to better understand the impact of Kombucha on the human body, but also to ensure the application of regulatory guidelines for its production and marketing and enable its safe and effective consumption.

Microbial, physicochemical and proximate analysis of Tej collected from Amhara regional state of Ethiopia

Tej is an Ethiopian traditional alcoholic beverage with significant social and economic importance. Due to the spontaneous fermentation process of Tej, several issues such as safety, quality, and physicochemical properties of the final products is rquired to be assessed. Thus, this study was aimed to assess the microbial quality, physicochemical, and proximate properties of Tej associated with different maturity time. The microbial, physicochemical and proximate analyses were carried out by standard protocol. Lactic acid bacteria (6.30 log CFU/mL) and yeast (6.22 log CFU/mL) were the dominat microorganisms of all Tej samples at different maturity time, with significant differences (p = 0.001) in mean microbial count among samples. The mean pH, titratable acidity and ethanol content of Tej samples were 3.51, 0.79 and 11.04% (v/v), respectively. There were significant differences (p = 0.001) among the mean pH and titratable acidity values. The mean proximate compositions (%) of Tej samples were as follows: moisture (91.88), ash (0.65), protein (1.38), fat (0.47) and carbohydrate (3.91). Statistically significant differences (p = 0.001) were observed in proximate compositions of Tej samples from different maturity time. Generally, Tej maturity time has a great impact on the improvement of nutrient composition and the increment of the acidic contents which in turn suppress the growth of unwanted microorganisms. Further evaluation of the biological, and chemical safety and development of yeast-LAB starter culture are strongly recommended to improve Tej fermentation in Ethiopia.

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.

Date Fruits as Raw Material for Vinegar and Non-Alcoholic Fermented Beverages

Currently, foods and beverages with healthy and functional properties, especially those that claim to prevent chronic diseases, are receiving more and more interest. As a result, numerous foods and beverages have been launched onto the market. Among the products with enhanced properties, vinegar and fermented beverages have a high potential for growth. Date palm fruits are a versatile raw material rich in sugars, dietary fibers, minerals, vitamins, and phenolic compounds; thus, they are widely used for food production, including date juice, jelly, butter, and fermented beverages, such as wine and vinegar. Furthermore, their composition makes them suitable for the formulation of functional foods and beverages. Microbial transformations of date juice include alcoholic fermentation for producing wine as an end-product, or as a substrate for acetic fermentation. Lactic fermentation is also documented for transforming date juice and syrup. However, in terms of acetic acid bacteria, little evidence is available on the exploitation of date juice by acetic and gluconic fermentation for producing beverages. This review provides an overview of date fruit’s composition, the related health benefits for human health, vinegar and date-based fermented non-alcoholic beverages obtained by acetic acid bacteria fermentation.

Kombucha analogues around the world: A review

Kombucha is a traditional healthy beverage usually made by the fermentation of sweetened tea with a symbiotic culture of bacteria and yeast. The consumption of kombucha is associated with numerous health benefits and therefore the beverage has attracted the attention of consumers worldwide. Non-typical substrates (fruits, vegetables, plants, herbs, dairy, and by-products) are being inoculated with the kombucha consortium in an attempt to develop new products. This review paper reviews the fermentation parameters for different non-tea substrates used to make kombucha, in addition to the findings obtained in terms of physico-chemical analysis, biological activities and sensory evaluation.

Fermentation with Tea Residues Enhances Antioxidant Activities and Polyphenol Contents in Kombucha Beverages

Kombucha is a popular beverage with various bioactivities (such as antioxidant activity), which can be attributed to its abundant bioactive compounds, especially polyphenols. Kombucha is conventionally prepared by fermentation of a sugared black tea infusion without tea residue. In this study, the effects of black tea residue and green tea residue on kombucha were studied, and its antioxidant activities, total phenolic contents, as well as concentrations of polyphenols at different fermentation stages were evaluated using ferric-reducing antioxidant power, Trolox equivalent antioxidant capacity, Folin-Ciocalteu method and high-performance liquid chromatography with a photodiode array detector. The results showed that fermentation with tea residue could markedly increase antioxidant activities (maximum 3.25 times) as well as polyphenolic concentrations (5.68 times) of kombucha. In addition, green tea residue showed a stronger effect than black tea residue. Overall, it is interesting to find that fermentation with tea residues could be a better strategy to produce polyphenol-rich kombucha beverages.

Strategies to Improve the Potential Functionality of Fruit-Based Fermented Beverages

It is only recently that fermentation has been facing a dynamic revival in the food industry. Fermented fruit-based beverages are among the most ancient products consumed worldwide, while in recent years special research attention has been granted to assess their functionality. This review highlights the functional potential of alcoholic and non-alcoholic fermented fruit beverages in terms of chemical and nutritional profiles that impact on human health, considering the natural occurrence and enrichment of fermented fruit-based beverages in phenolic compounds, vitamins and minerals, and pro/prebiotics. The health benefits of fruit-based beverages that resulted from lactic, acetic, alcoholic, or symbiotic fermentation and specific daily recommended doses of each claimed bioactive compound were also highlighted. The latest trends on pre-fermentative methods used to optimize the extraction of bioactive compounds (maceration, decoction, and extraction assisted by supercritical fluids, microwave, ultrasound, pulsed electric fields, high pressure homogenization, or enzymes) are critically assessed. As such, optimized fermentation processes and post-fermentative operations, reviewed in an industrial scale-up, can prolong the shelf life and the quality of fermented fruit beverages.