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.

Differential consumption of malic acid and fructose in apple musts by Pichia kudriavzevii strains

AIMS

To assess the capability of Pichia kudriavzevii strains isolated from wine, cider, and natural environments in North Patagonia to produce ciders with reduced malic acid levels.

METHODS AND RESULTS

Fermentation kinetics and malic acid consumption were assessed in synthetic media and in regional acidic apple musts. All P. kudriavzevii strains degraded malic acid and grew in synthetic media with malic acid as the sole carbon source. Among these strains, those isolated from cider exhibited higher fermentative capacity, mainly due to increased fructose utilization; however, a low capacity to consume sucrose present in the must was also observed for all strains. The NPCC1651 cider strain stood out for its malic acid consumption ability in high-malic acid Granny Smith apple must. Additionally, this strain produced high levels of glycerol as well as acceptable levels of acetic acid. On the other hand, Saccharomyces cerevisiae ÑIF8 reference strain isolated from Patagonian wine completely consumed reducing sugars and sucrose and showed an important capacity for malic acid consumption in apple must fermentations.

CONCLUSIONS

Pichia kudriavzevii NPCC1651 strain isolated from cider evidenced interesting features for the consumption of malic acid and fructose in ciders.

Evaluation of the Efficacy of Kombucha-Based Drink Enriched with Inulin and Vitamins for the Management of Constipation-Predominant Irritable Bowel Syndrome in Females: A Randomized Pilot Study

Background

Constipation-predominant irritable bowel syndrome (IBS-C) mainly affects females, and dietary interventions for symptom relief often yield poor results because of low patient adherence. The development of functional food products enriched with dietary fibers may increase patients' adherence to a healthy diet and relieve IBS-С symptoms.

Objective

This proof-of-concept, open-label, randomized controlled pilot study is aimed to evaluate the efficacy of kombucha enriched with inulin and vitamins in females with IBS-C.

Methods

Forty females with IBS-C were randomly assigned to receive either 220 mL of kombucha enriched with inulin (2.53 g/220 mL) and vitamins (B1 - 0.59 mg, B2 - 0.55 mg, B3 - 5.9 mg, B6 - 0.7 mg, and folic acid - 81.4 μg/220 mL) or water for 10 d. Stool frequency, Bristol stool scale score (BSSS), and abdominal symptoms were evaluated using a 5-point Likert scale on days 5, 9 and 14 of the study. The palatability of the drink was assessed using a visual analog scale.

Results

After 10 d, the kombucha group showed a significant increase in stool frequency (0.60 ± 0.31-0.85 ± 0.19 times/d; P = 0.004) compared with the control (0.63 ± 0.33 compared with 0.72 ± 0.28; P = 0.6). The mean values of the BSSS increased in the kombucha group (3.0 ± 1.2-4.4 ± 1.0; P = 0.001), whereas they remained unchanged in the control (2.9 ± 1.2 compared with 3.4 ± 1.2; P = 0.6). The kombucha group also experienced a significant decrease in the feeling of incomplete bowel emptying (1.88 ± 0.78 compared with 1.41 ± 0.56 points; P = 0.015), which was not observed in the control group.

Conclusions

Short-term consumption of kombucha enriched with inulin and vitamins was associated with an increase in stool frequency, an improvement in the BSSS, and a reduction in the feeling of incomplete bowel emptying in females with IBS-C. Further large-scale clinical trials investigating the efficacy of kombucha enriched with inulin and vitamins in patients with IBS-C are warranted to prove the observed effects.

Trial registration number

This trial was registered at clinicaltrials.gov as NCT05164861 (==https://clinicaltrials.gov/study/NCT05164861?term=NCT05164861&rank=1; registered on 18 December, 2021).

Characterization of the Bacterial Composition of 47 Fermented Foods in Sweden

Fermentation has long been utilized to preserve and enhance the flavor and nutritional value of foods. Recently, fermented foods have gained popularity, reaching new consumer groups due to perceived health benefits. However, the microbial composition of many fermented foods re-mains unknown. Here, we characterized the bacterial composition, diversity, and richness of 47 fermented foods available in Sweden, including kombucha, water kefir, milk kefir, yogurt, plant-based yogurt alternatives, kimchi, sauerkraut, and fermented vegetables. Via 16S rRNA gene sequencing, we identified 2497 bacteria (amplicon sequence variants). The bacterial composition was strongly associated with the type of fermented food, and lactic acid bacteria and/or acetic acid bacteria dominated most samples. However, each fermented food had a unique composition, with kombucha and water kefir having the highest diversity across and within samples. Few bacteria were abundant in multiple foods and food groups. These were Streptococcus thermophilus in yogurts and plant-based yoghurts; Lactococcus lactis in milk kefirs and one water kefir; and Lactiplantibacillus plantarum in kimchi, sauerkraut, and fermented cucumber. The broad range of fermented foods included in this study and their diverse bacterial communities warrant further investigation into the implications of microbial compositions for product traits and potential impact on human health.

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.

Millennial drinks: acidity, fluoride content, and enamel softening

This in vitro study aimed to evaluate the acidity and fluoride content of beverages commonly consumed by millennials and the enamel-softening effect of these drinks on tooth enamel. The study included 13 beverages in 4 categories: energy (sports) drink, flavored sparkling water, kombucha, and other (an unsweetened iced tea, a vegetable-fruit juice blend, and a soft drink). The acidity was measured with a pH/ion meter, and the fluoride concentration was measured with a combined fluoride electrode coupled to the meter (n = 10 measurements per beverage). The Vickers hardness number of extracted molars was measured before and after a 30-minute immersion in 4 representative beverages via 2 immersion protocols (n = 10 per beverage per protocol): (1) immersion in the beverage only and (2) immersion alternating between the beverage and artificial saliva every other minute. The pH and fluoride concentrations of the beverages ranged from 2.652 to 4.242 and from 0.0033 to 0.6045 ppm, respectively. One-way analysis of variance (ANOVA) revealed that all differences between beverages in pH values were statistically significant, as were the majority of differences in fluoride concentrations (P < 0.001). The beverages and the 2 immersion methods significantly affected enamel softening (2-way ANOVA, P = 0.0001 to 0.033). The representative energy drink (pH 2.990; 0.0102 ppm fluoride) caused the greatest enamel softening followed by the representative kombucha (pH 2.820; 0.2036 ppm fluoride). The representative flavored sparkling water (pH 4.066; 0.0098 ppm fluoride) caused significantly less enamel softening than the energy drink and kombucha. A root beer (pH 4.185; 0.6045 ppm fluoride) had the least enamel softening effect. All tested beverages were acidic and had a pH below 4.5; only some contained fluoride. Flavored sparkling water, likely due to its higher pH, caused less enamel softening than the tested energy drink and kombucha. The fluoride content of kombucha and root beer lower their enamel-softening effects. It is imperative that consumers be aware of the erosive potential of beverages they consume.

Innovative beverage creation through symbiotic microbial communities inspired by traditional fermented beverages: current status, challenges and future directions

Fermented beverages (FBs) are facing challenges in functional performance and flavor complexity, necessitating the development of new multi-functional options. Traditional fermented beverages (TFBs), both alcoholic and nonalcoholic, have gained increased attention for their health-promoting effects during the COVID-19 pandemic. This review summarized the primary commercially available probiotics of FBs, along with the limitations of single and mixed probiotic FBs. It also examined the recent research progress on TFBs, emphasizing the typical microbial communities (MC) of TFBs, and TFBs made from crops (grains, vegetables, fruits, etc.) worldwide and their associated functions and health benefits. Furthermore, the construction, technical bottlenecks of the synthetic MC involved in developing innovative FBs were presented, and the promising perspective of FBs was described. Drawing inspiration from the MC of TFBs, developing of stable and multifunctional FBs using synthetic MC holds great promise for beverage industry. However, synthetic MC suffers from structural instability and poorly acknowledged interaction mechanisms, resulting in disappointing results in FBs. Future researches should prioritize creating synthetic MC fermentation that closely resemble natural fermentation, tailored to meet the needs of different consumers. Creating personalized FBs with high-tech intelligence is vital in attracting potential consumers and developing novel beverages for the future.

Potential neuroprotective effects of fermented foods and beverages in old age: a systematic review

Purpose

Numerous articles have recently studied the involvement of the gut microbiota in neurological diseases. Aging is associated with changes in the microbiome, which implies a reduction in microbial biodiversity among other changes. Considering that the consumption of a fermented-food diet improves intestinal permeability and barrier function, it seems of interest to study its participation in the prevention of neurodegenerative diseases. This article reviews existing studies to establish whether the consumption of fermented foods and fermented beverages prevents or ameliorates neurodegenerative decline in old age.

Methods

The protocol used was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Details of the protocol for this systematic review are registered on PROSPERO (CRD42021250921).

Results

Out of 465 articles identified in the Pubmed, Scopus, and Cochrane Library databases, a total of 29 that examined the relationship of the consumption of fermented products with cognitive impairment in old people were selected (22 cohort, 4 case-control, and 3 cross-sectional studies). The results suggest that low-to-moderate alcohol consumption and daily intake of coffee, soy products, and fermented-food diets in general are associated with a lower risk of dementia and Alzheimer's disease.

Conclusion

Daily consumption of fermented foods and beverages, either alone or as part of a diet, has neuroprotective effects and slows cognitive decline in old people.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=250921, identifier: CRD42021250921.

Effect of Gastrointestinal Digestion on the Bioaccessibility of Phenolic Compounds and Antioxidant Activity of Fermented Aloe vera Juices

Plant-based beverages are enriched by the fermentation process. However, their biocompounds are transformed during gastrointestinal digestion, improving their bioaccessibility, which is of primary importance when considering the associated health benefits. This study aimed to evaluate the effect of in vitro gastrointestinal digestion on phenolic compound bioaccessibility and antioxidant activity of novel Aloe vera juices fermented by probiotic Enterococcus faecium and Lactococcus lactis. Aloe vera juices were digested using the standardized static INFOGEST protocol. During digestion, phenolic compounds and antioxidant activity (DPPH, ABTS, and FRAP) were accessed. The digestion process was seen to significantly increase the total phenolic content of the fermented Aloe vera juices. The fermentation of Aloe vera increased the bioaccessibility of juice biocompounds, particularly for kaempferol, ellagic acid, resveratrol, hesperidin, ferulic acid, and aloin. The phenolics released during digestion were able to reduce the oxidative radicals assessed by ABTS and FRAP tests, increasing the antioxidant action in the intestine, where they are absorbed. The fermentation of Aloe vera by probiotics is an excellent process to increase the bioavailability of beverages, resulting in natural added-value functional products.

Aloe Vera-Fermented Beverage Ameliorates Obesity and Gut Dysbiosis in High-Fat-Diet Mice

Aloe vera has been proven to have various medicinal properties, including anti-inflammatory and anti-obesity functions. However, the effects of Aloe vera-fermented beverages (AFB) on obesity and its complications are still not clear. In this study, HepG2 cells in high-fat environment and high-fat diet (HFD) mice were used to investigate the potential obesity-preventing function of AFB. We found that AFB intervention decreased the amount of lipid droplets of HepG2 cells, suppressed the body weight gain and adipose accumulation, and reduced the serum contents of total cholesterol (TC), alanine aminotransferase (ALT), and interleukin 10 (IL-10) of HFD-mice. In addition, it also changed the composition of the gut microbiota. The ratio of Firmicutes/Bacteroidetes was decreased, while the relative abundance of Muribaculaceae, Alistipes and Rikenellaceae_RC9_gut_group was increased after the administration of AFB compared with HFD-mice. These results demonstrated that AFB can prevent diet-induced obesity (DIO) and provides a new option to modulate obesity-related gut dysbiosis.

Effect of Hop Varieties and Forms in the Hopping Process on Non-Alcoholic Beer Quality

The aim of this study was to determine how the hopping technique affects the quality of non-alcoholic beer (NAB). A series of NABs were brewed and tested for basic physicochemical characteristics, profiles of selected volatile compounds, and microbial contamination. The brewing process yielded 13 experimental groups of beers, all of which had an ethanol content of <0.5%v/v. Among the batches brewed with ‘Marynka’ hops, the pellet form was found to provide the highest concentrations of hop-derived volatile compounds, whereas in the ‘Magnum’ groups, the extracts and whole hops proved superior. Humulene and caryophyllene were the primary volatiles in terms of quantity. All the brews were contamination-free—no microbes other than yeast cells were detected. Their microbiological purity was also supported by an assay of beer-defect indicators (volatile compounds), which only showed low levels of acetaldehyde, 1-propanol, 2-methylbutanol, and 3-methylbutanol. The hopping technique deployed was found not to affect the physicochemical parameters of NABs, but did have a significant impact on their volatile compound profile.

Microbial Communities of Artisanal Fermented Milk Products from Russia

Fermented milk products (FMPs) have numerous health properties, making them an important part of our nutrient budget. Based on traditions, history and geography, there are different preferences and recipes for FMP preparation in distinct regions of the world and Russia in particular. A number of dairy products, both widely occurring and region-specific, were sampled in the households and local markets of the Caucasus republics, Buryatia, Altai, and the Far East and European regions of Russia. The examined FMPs were produced from cow, camel, mare’s or mixed milk, in the traditional way, without adding commercial starter cultures. Lactate and acetate were the major volatile fatty acids (VFA) of the studied FMPs, while succinate, formate, propionate and n-butyrate were present in lower concentrations. Bacterial communities analyzed by 16S rRNA gene V4 fragment amplicon sequencing showed that Firmicutes (Lactococcus, Lactobacillus, Streptococcus, Lentilactobacillus and Leuconostoc) was the predominant phylum in all analyzed FMPs, followed by Proteobacteria (Acetobacter, Klebsiella, Pseudomonas and Citrobacter). Lactobacillus (mainly in beverages) or Lactococcus (mainly in creamy and solid products) were the most abundant community-forming genera in FMPs where raw milk was used and fermentation took place at (or below) room temperature. In turn, representatives of Streptococcus genus dominated the FMPs made from melted or pasteurized milk and fermented at elevated temperatures (such as ryazhenka, cottage cheese and matsoni-like products). It was revealed that the microbial diversity of koumiss, shubat, ryazhenka, matsoni-like products, chegen, sour cream and bryndza varied slightly within each type and correlated well with the same products from other regions and countries. On the other hand, the microbiomes of kefir, prostokvasha, ayran, cottage cheese and suluguni-like cheese were more variable and were shaped by the influence of particular factors linked with regional differences and traditions expressed in specificities in the production process. The microbial diversity of aarts, khurunga, khuruud, tan, ayran and suluguni-like cheese was studied here, to our knowledge, for the first time. The results of this study emphasize the overall similarity of the microbial communities of various FMPs on the one hand, and specificities of regional products on the other. The latter are of particular value in the age of globalization when people have begun searching for new and unusual products and properties. Speaking more specifically, these novel products, with their characteristic communities, might be used for the development of novel microbial associations (i.e., starters) to produce novel products with improved or unique properties.

Investigation of the Phageome and Prophages in French Cider, a Fermented Beverage

Phageomes are known to play a key role in the functioning of their associated microbial communities. The phageomes of fermented foods have not been studied thoroughly in fermented foods yet, and even less in fermented beverages. Two approaches were employed to investigate the presence of phages in cider, a fermented beverage made from apple, during a fermentation process of two cider tanks, one from an industrial producer and one from a hand-crafted producer. The phageome (free lytic phages) was explored in cider samples with several methodological developments for total phage DNA extraction, along with single phage isolation. Concentration methods, such as tangential flow filtration, flocculation and classical phage concentration methods, were employed and tested to extract free phage particles from cider. This part of the work revealed a very low occurrence of free lytic phage particles in cider. In parallel, a prophage investigation during the fermentation process was also performed using a metagenomic approach on the total bacterial genomic DNA. Prophages in bacterial metagenomes in the two cider tanks seemed also to occur in low abundance, as a total of 1174 putative prophages were identified in the two tanks overtime, and only two complete prophages were revealed. Prophage occurrence was greater at the industrial producer than at the hand-crafted producer, and different dynamics of prophage trends were also observed during fermentation. This is the first report dealing with the investigation of the phageome and of prophages throughout a fermentation process of a fermented beverage.

Moderate Beer Intake Downregulates Inflammasome Pathway Gene Expression in Human Macrophages

Simple Summary

Moderate consumption of fermented beverages is associated with prevention against diseases involving inflammation and immunity. Conversely, for high drinking levels, an increase of inflammatory mediators and the susceptibility to infections occur, which tend to offset the benefits in terms of health. Unfortunately, this area remains poorly understood. Inflammation is now recognized as an overwhelming burden for public health. Thus, subcellular molecular complexes such as the “inflammasomes” have been identified as key players in cellular stress and tissue damage, and as regulators of immune and inflammatory responses. Here, we investigated the impact of moderate intake of alcohol-free and traditional beer in humans on the inflammasome pathway of activated pro-inflammatory human macrophages. The results of this study showed that macrophages submitted to a pro-inflammatory stimulus to activate the inflammosome had a mitigated inflammatory response in the presence of blood serum obtained from healthy volunteers after consuming alcohol-free or traditional beer for four weeks (women one can and men two cans per day) compared to the response found in the presence of blood serum obtained before beer intake. This was shown by a decrease in end components of the inflammasome cascade (IL-1β and TNF) at gene expression and protein level as found with alcohol-free and traditional beer, respectively.

Abstract

Inflammasomes are key components of the innate immunity system that trigger the inflammatory response. Inappropriate activity of the inflammasome system has been linked to onset and perpetuation of inflammation in atherosclerotic plaques and cardiovascular disease. Low-to-moderate beer consumption is inversely associated with cardiovascular event presentation, while high levels of alcohol intake are associated with increased cardiovascular risk. Although fermented beverages have been suggested to exert their beneficial effects through their anti-oxidant and anti-inflammatory properties, little is known regarding the capacity of beer to modulate innate immunity cell responses. To this aim, primed or activated THP-1 macrophages were conditioned with human serum obtained from a prospective two-arms longitudinal crossover study to investigate the effect of a moderate and regular daily intake of beer, either alcohol-free or traditional, in the regulation of TLR-mediated inflammatory responses in healthy but overweight individuals. Conditioned macrophages with serum obtained after four-week intervention with alcohol-free beer significantly reduced the transcription of pro-inflammatory interleukins such as IL-1β and TNF. The serum of traditional beer consumers did not exhibit the same capacity as the serum of alcohol-free beer consumers to reduce gene expression of pro-inflammatory interleukins; however, serum from traditional beer consumers showed a regulatory effect at the protein level by significantly decreasing the intracellular protein levels of pro-IL-1β in primed macrophages and preventing cleaved-IL-1β protein release.

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.

Exopolysaccharides Producing Lactic Acid Bacteria in Wine and Other Fermented Beverages: For Better or for Worse?

Lactic acid bacteria (LAB) from fermented beverages such as wine, cider and beer produce a wide range of exopolysaccharides (EPS) through multiple biosynthetic pathways. These extracellular polysaccharides constitute key elements for bacterial species adaptation to such anthropic processes. In the food industry, LAB polysaccharides have been widely studied for their rheological, functional and nutritional properties; however, these have been poorly studied in wine, beer and cider until recently. In this review, we have gathered the information available on these specific polysaccharide structure and, biosynthetic pathways, as well as the physiology of their production. The genes associated with EPS synthesis are also presented and compared. Finally, the possible role of EPS for bacterial survival and spread, as well as the risks or possible benefits for the winemaker and the wine lover, are discussed.

Impact of Oral Microbiota on Flavor Perception: From Food Processing to In-Mouth Metabolization

Flavor perception during food intake is one of the main drivers of food acceptability and consumption. Recent studies have pointed to the oral microbiota as an important factor modulating flavor perception. This review introduces general characteristics of the oral microbiota, factors potentially influencing its composition, as well as known relationships between oral microbiota and chemosensory perception. We also review diverse evidenced mechanisms enabling the modulation of chemosensory perception by the microbiota. They include modulation of the chemosensory receptors activation by microbial metabolites but also modification of receptors expression. Specific enzymatic reactions catalyzed by oral microorganisms generate fragrant molecules from aroma precursors in the mouth. Interestingly, these reactions also occur during the processing of fermented beverages, such as wine and beer. In this context, two groups of aroma precursors are presented and discussed, namely, glycoside conjugates and cysteine conjugates, which can generate aroma compounds both in fermented beverages and in the mouth. The two entailed families of enzymes, i.e., glycosidases and carbon-sulfur lyases, appear to be promising targets to understand the complexity of flavor perception in the mouth as well as potential biotechnological tools for flavor enhancement or production of specific flavor compounds.

Identification of new ethanol-tolerant yeast strains with fermentation potential from central Patagonia

The quest for new wild yeasts has increasingly gained attention because of their potential ability to provide unique organoleptic characters to fermented beverages. In this sense, Patagonia offers a wide diversity of ethanol-tolerant yeasts and stands out as a bioprospecting alternative. This study characterized the genetic and phenotypic diversity of yeast isolates obtained from Central Chilean Patagonia and analyzed their fermentation potential under different fermentative conditions. We recovered 125 colonies from Nothofagus spp. bark samples belonging to five yeast species: Saccharomyces eubayanus, Saccharomyces uvarum, Lachancea cidri, Kregervanrija delftensis, and Hanseniaspora valbyensis. High-throughput microcultivation assays demonstrated the extensive phenotypic diversity among Patagonian isolates, where Saccharomyces spp and L. cidri isolates exhibited the most outstanding fitness scores across the conditions tested. Fermentation performance assays under wine, mead, and beer conditions demonstrated the specific potential of the different species for each particular beverage. Saccharomyces spp. were the only isolates able to ferment beer wort. Interestingly, we found that L. cidri is a novel candidate species to ferment wine and mead, exceeding the fermentation capacity of a commercial strain. Unlike commercial strains, we found that L. cidri does not require nutritional supplements for efficient mead fermentation. In addition, L. cidri produces succinic and acetic acids, providing a distinct profile to the final fermented product. This work demonstrates the importance of bioprospecting efforts in Patagonia to isolate novel wild yeast strains with extraordinary biotechnological potential for the fermentation industry.

Changes in the Antioxidative Activity and the Content of Phenolics and Iridoids during Fermentation and Aging of Natural Fruit Meads

The aim of the study was to investigate changes in the content of biologically active compounds during the fermentation and aging of natural meads with the addition of three Cornelian cherry juices from three cultivars: 'Koralovyi', 'Podolski' and 'Yantarnyi', in the amount of 10% v/v. After the fermentation process the content of gallic and ellagic acids significantly increased, in relation to wort. Whereas the greatest losses were observed among unstable anthocyanins. The three-month aging process also reduced the content of the analyzed compounds except for ellagic acid, the content of which increased by up to 90%. The content of biologically active compounds, including iridoids and antioxidant phenolics, are constantly changing in the process of fermentation and aging of fruit meads. The studies proved that the addition of Cornelian cherry juice allows significantly enriched classic meads with new biologically active compounds, such as: exceptional iridoids (loganic acid, cornuside, loganine, sweroside), flavonols, phenolic acids and anthocyanins.

Bioconversion of Milk Permeate with Selected Lactic Acid Bacteria Strains and Apple By-Products into Beverages with Antimicrobial Properties and Enriched with Galactooligosaccharides

The present research study aims to prepare prototypes of beverages from milk permeate (MP) using fermentation with 10 different strains of lactic acid bacteria (LAB) showing antimicrobial properties (L. uvarum LUHS245, L. casei LUHS210, L. curvatus LUHS51, L. plantarum LUHS135, P. acidilactici LUHS29, L. plantarum LUHS122, L. coryniformins LUHS71, L. paracasei LUHS244, P. pentosaceus LUHS183, L. faraginis LUHS206) and MP with (AppMP) or without (MP) the addition of 8% (w/w) apple by-products (App). Two groups of prototypes of beverages were prepared: fermented MP and fermented MP with App (AppMP). Acidity parameters, LAB viable counts, lactose and galactooligosaccharides (GOSs) content, antimicrobial properties against 15 pathogenic and opportunistic bacterial strains, overall acceptability and emotions induced of the final fermented beverages for consumers were evaluated. Results showed that all LAB grew well in MP and LAB strain exhibited a significant (p ≤ 0.05) influence on galactobiose and galactotriose synthesis in the fermentable MP substrate. The highest total content of GOS (26.80 mg/100 mL) was found in MPLUHS29 fermented beverage. In addition, MPLUHS245, MPLUHS210 and AppMPLUHS71 fermented beverages showed high antimicrobial activity, inhibiting 13 out of 15 tested microbial pathogens. The overall acceptability of AppMP fermented beverages was 26.8% higher when compared with fermented beverages without App (MP), and the most intensive "happy" emotion was induced by MPLUHS71, MPLUHS24, MPLUHS183 and MPLUHS206 samples. Finally, very promising results were also attained by the bioconversion of MP with selected LAB and App addition into the prototypes of antimicrobial beverages enriched with GOS.

Phage community involvement in fermented beverages: an open door to technological advances?

Bacteriophages (phages) are considered the most abundant biological entities on Earth. An increasing interest in understanding phage communities, also called viromes or phageomes, has arisen over the past decade especially thanks to the development and the accessibility of Next Generation Sequencing techniques. Despite the increasing amount of available metagenomic data on microbial communities in various habitats, viromes remain poorly described in the scientific literature particularly when it comes to fermented food and beverages such as wine and cider. In this review, a particular attention is paid to the current knowledge on phage communities, with a special focus on fermented food viromes and the methodological tools available to undertake their study. There is a striking lack of available data on the fermented foods and beverages viromes. As far as we know, and although a number of phages have been isolated from wine, no general study has to date been carried out to assess the diversity of viromes in fermented beverages and their possible interactions with microbiota throughout the fermentation process. With the aim of establishing connections between the currently used technologies to carry out the analysis of viromes, possible applications of current knowledge to fermented beverages are examined.

Color Stability of Fermented Mare's Milk and a Fermented Beverage from Cow's Milk Adapted to Mare's Milk Composition

Color is important for the consumer when making a purchase decision. Mare’s milk and, thus, fermented mare’s milk is little known to consumers. Thus, it is worth presenting research showing the extent of color change during the production and storage of mare’s milk. Herein, we examined the range of color changes in mare’s milk and cow’s milks adapted to mare’s milk composition. These samples were further fermented and stored for 3 weeks at 5 ± 1 °C. Starter cultures containing Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus were used for fermentation. Mare’s milk reached the required pH of 4.5 during fermentation faster (255 min) than cow’s milk (300 min). After fermentation, mare’s milk compared to cow’s milk and adapted cow’s milk had lower titratable acidity (0.75%) and firmness (145. 6 |(g∙s)|). The water holding capacity (95.6%) and number of Lactobacillus (7.71 log CFU/mL) and Streptocococcus (7.20 log CFU/mL) in mare’s and other’s milks were the same. Mare’s milk was furthest from the ideal white (WI) color, with its chrome (C*) being 1.5-times larger than cow’s milk. However, fermented mare’s milk was darker than the fermented adapted milk and cow’s milk by 36% and 58%, respectively. Storage caused a decrease in the WI, C*, and yellowness index (YI). The fermented mare’s milk color stability during production and storage was less than that of fermented cow’s milk. After 3 weeks storage, it was observed that the titratable acidity increased to 1.05%, and the pH decreased to 4.3 in fermented mare’s milk. The water holding capacity decreased but was still higher compared to fermented cow’s milk.

Validation of a LLME/GC-MS Methodology for Quantification of Volatile Compounds in Fermented Beverages

Knowledge of composition of beverages volatile fraction is essential for understanding their sensory attributes. Analysis of volatile compounds predominantly resorts to gas chromatography coupled with mass spectrometry (GC-MS). Often a previous concentration step is required to quantify compounds found at low concentrations. This work presents a liquid-liquid microextraction method combined with GC-MS (LLME/GC-MS) for the analysis of compounds in fermented beverages and spirits. The method was validated for a set of compounds typically found in fermented beverages comprising alcohols, esters, volatile phenols, and monoterpenic alcohols. The key requirements for validity were observed, namely linearity, sensitivity in the studied range, accuracy, and precision within the required parameters. Robustness of the method was also evaluated with satisfactory results. Thus, the proposed LLME/GC-MS method may be a useful tool for the analysis of several fermented beverages, which is easily implementable in a laboratory equipped with a GC-MS.

Glycolytic Proteins Interact With Intracellular Melatonin in Saccharomyces cerevisiae

Melatonin is a bioactive compound that is present in fermented beverages and synthesized by yeast during alcoholic fermentation. Many studies have shown that melatonin interacts with some mammalian proteins, such as sirtuins or orphan receptor family proteins. The aim of this study was to determine the intracellular synthesis profile of melatonin in Saccharomyces cerevisiae and to identify the proteins that may interact with this molecule in yeast cells. Melatonin from fermentation samples was analyzed by liquid chromatography mass spectrometry, and proteins bound to melatonin were immunopurified by melatonin-IgG-Dynabeads. Melatonin was produced intracellularly in the lag phase of yeast growth and was exported to the extracellular media during the stationary phase. During this period, melatonin was bound to six proteins with molecular weights from 55 to 35 kDa. Sequence analysis showed that most proteins shared high levels of homology with glycolytic enzymes. An RNA-binding protein was also identified, the elongation alpha factor, which is related to mitochondria. This study reports for the first time the interaction of melatonin and proteins inside yeast cells. These results highlight the possible role of melatonin as a signal molecule and provide a new perspective for understanding its role in yeast.

Kombucha from alternative raw materials - The review

Nowadays, people's awareness about the role of diet in maintaining well-being and good health has increased. Consumers expect that the products not only provide them with essential nutrients but will also be a source of biologically active substances, which are beneficial to their health. One of the "healthy trends," which has appeared among the consumers worldwide is kombucha, a tea drink with high antioxidant potential, obtained through the activity of a consortium of acetic acid bacteria and osmophilic yeast, which is also called "tea fungus." Kombucha obtained from tea is characterized by its health-promoting properties. Promising results in in vitro and in vivo studies have prompted research groups from around the world to search for alternative raw materials for tea fungus fermentation. Attempts are made to obtain functional beverages from leaves, herb infusions, vegetable pulp, fruit juices, or milk. This review focuses on describing the progress in obtaining a fermented beverage and bacterial cellulose using tea fungus on alternative raw materials.

Anthocyanins and Anthocyanin-Derived Products in Yeast-Fermented Beverages

The beverages obtained by yeast fermentation from anthocyanin-rich natural sources (grapes, berries, brown rice, etc.) retain part of the initial pigments in the maturated drink. During the fermentation and aging processes anthocyanins undergo various chemical transformations, which include reactions with glycolytic products (especially pyruvate and acetaldehyde) or with other compounds present in the complex fermentation milieu (such as vinylphenols obtained from cinnamic acids by means of a yeast decarboxylase) yielding pigments which can be more stable than the initial anthocyanins. Overall, these compounds contribute to the organoleptic traits of the mature product, but also to the overall chemical composition which make the yeast fermented beverages important sources of dietary antioxidants. In this review, we focused on the studies regarding the changes underwent by anthocyanins during yeast-mediated fermentation, on the approaches taken to enrich the fermented beverages in anthocyanins and their derived products, and on the interrelations between yeast and anthocyanin which were of relevance for obtaining a high-quality product containing optimum amounts of anthocyanin and anthocyanin-derived products.

Rapid Quantification of Major Volatile Metabolites in Fermented Food and Beverages Using Gas Chromatography-Mass Spectrometry

Here we present a method for the accurate quantification of major volatile metabolites found in different food and beverages, including ethanol, acetic acid and other aroma compounds, using gas chromatography coupled to mass spectrometry (GC-MS). The method is combined with a simple sample preparation procedure using sodium chloride and anhydrous ethyl acetate. The GC-MS analysis was accomplished within 4.75 min, and over 80 features were detected, of which 40 were positively identified using an in-house and a commercialmass spectrometry (MS) library. We determined different analytical parameters of these metabolites including the limit of detection (LOD), limit of quantitation (LOQ) and range of quantification. In order to validate the method, we also determined detailed analytical characteristics of five major fermentation end products including ethanol, acetic acid, isoamyl alcohol, ethyl-L-lactate and, acetoin. The method showed very low technical variability for the measurements of these metabolites in different matrices (<3%) with an excellent accuracy (100% ± 5%), recovery (100% ± 10%), reproducibility and repeatability [Coefficient of variation (CV) 1-10%)]. To demonstrate the applicability of the method, we analysed different fermented products including balsamic vinegars, sourdough, distilled (whisky) and non-distilled beverages (wine and beer).

Antioxidant and Angiotensin-Converting Enzyme Inhibitory Activity of Eucalyptus camaldulensis and Litsea glaucescens Infusions Fermented with Kombucha Consortium

Physicochemical properties, consumer acceptance, antioxidant and angiotensin-converting enzyme (ACE) inhibitory activities of infusions and fermented beverages of Eucalyptus camaldulensis and Litsea glaucescens were compared. Among physicochemical parameters, only the pH of fermented beverages decreased compared with the unfermented infusions. No relevant changes were reported in consumer preference between infusions and fermented beverages. Phenolic profile measured by UPLC MS/MS analysis demonstrated significant concentration changes of these compounds in plant infusions and fermented beverages. Fermentation induced a decrease in the concentration required to stabilize 50% of DPPH radical (i.e. lower IC50). Additionally, it enhanced the antioxidant activity measured by the nitric oxide scavenging assay (14% of E. camaldulensis and 49% of L. glaucescens); whereas relevant improvements in the fermented beverage were not observed in the lipid oxidation assay compared with unfermented infusions. The same behaviour was observed in the inhibitory activity of ACE; however, both infusions and fermented beverages had lower IC50 than positive control (captopril). The present study demonstrated that fermentation has an influence on the concentration of phenolics and their potential bioactivity. E. camaldulensis and L. glaucescens can be considered as natural sources of biocompounds with antihypertensive potential used either as infusions or fermented beverages.

Biopolymers from lactic acid bacteria. Novel applications in foods and beverages

Lactic acid bacteria (LAB) are microorganisms widely used in the fermented food industry worldwide. Certain LAB are able to produce exopolysaccharides (EPS) either attached to the cell wall (capsular EPS) or released to the extracellular environment (EPS). According to their composition, LAB may synthesize heteropolysaccharides or homopolysaccharides. A wide diversity of EPS are produced by LAB concerning their monomer composition, molecular mass, and structure. Although EPS-producing LAB strains have been traditionally applied in the manufacture of dairy products such as fermented milks and yogurts, their use in the elaboration of low-fat cheeses, diverse type of sourdough breads, and certain beverages are some of the novel applications of these polymers. This work aims to collect the most relevant issues of the former reviews concerning the monomer composition, structure, and yields and biosynthetic enzymes of EPS from LAB; to describe the recently characterized EPS and to present the application of both EPS-producing strains and their polymers in the fermented (specifically beverages and cereal-based) food industry.

Ethnobotany of wild plants used for starting fermented beverages in Shui communities of southwest China

BACKGROUND

Shui communities of southwest China have an extensive history of using wild plants as starters (Xiaoqu) to prepare fermented beverages that serve important roles in interpersonal relationships and cultural events. While the practice of using wild plants as starters for the preparation of fermented beverages was once prevalent throughout China, this tradition has seen a decline nationally since the 1930s. The traditional technique of preparing fermented beverages from wild plant starters remains well preserved in the Shui communities in southwest China and provides insight on local human-environment interactions and conservation of plant biodiversity for cultural purposes. The present study sought to examine the ethnobotany of wild plants used as starters for the preparation of fermented beverages including an inventory of plants used as a starter in liquor fermentation and associated knowledge and practices.

METHODS

Field surveys were carried out that consisted of semi-structured surveys and plant species inventories. One hundred forty-nine informants in twenty Shui villages were interviewed between July 2012 and October 2014 to document knowledge associated with wild plants used as a liquor fermentation starter. The inventories involved plant voucher specimens and taxonomic identification of plant collections.

RESULTS

A total of 103 species in 57 botanical families of wild plants were inventoried and documented that are traditionally used as starters for preparing fermented beverages by Shui communities. The majority of the species (93.2%) have multiple uses in addition to being used as a starter with medicinal purposes being the most prevalent. Shui women are the major harvesters and users of wild plants used as starters for preparing fermented beverages and transfer knowledge orally from mother to daughter.

CONCLUSIONS

Findings from this study can serve as a basis for future investigation on fermented beverages and foods and associated knowledge and cultural practices. However, with rapid development, utilization of wild plants and the cultural systems that support them are at risk of erosion. Cultural preservation practices are necessary in Shui communities for the continued use and transmission of this ethnobiological knowledge as well as associated biodiversity.