Recently, the increase in microbreweries and the consequent production of craft beers have reached exponential growth. The interest in non-conventional yeasts for innovation and a unique selling ...feature in beer fermentation is increasing. This work studied the autochthonous Saccharomyces and non-Saccharomyces yeasts, isolated from various food sources, with the ability to modify and improve the fermentative and aromatic profiles during alcoholic fermentation. The ability to ferment maltose and produce desirable aroma compounds were considered as the key characters for the screening selection. A synthetic beer wort was developed for this purpose, to simulate beer wort composition.
A total of forty-seven yeast strains belonging to different genera were analysed according to their fermentation profile, volatile compounds production and sensory analysis. Three native strains of Saccharomyces cerevisiae, Zygoascus meyerae and Pichia anomala were selected to evaluate their aromatic profile in single and mixed fermentations. The strains produced 4-vinylguaiacol, β-phenylethyl alcohol, and isoamyl alcohol at levels significantly above the sensory threshold, making them interesting for wheat and blond craft beer styles. The native Hanseniaspora vineae was also included in a co-fermentation treatment, resulting in a promising yeast to produce fruity beers.
•A synthetic beer wort was developed to simulate beer wort composition.•Z. meyerae, P. anomala and H. vineae were the selected non-conventional yeasts.•Aroma compounds produced were promising for wheat and blond craft beer styles.•High ester production by Hanseniaspora vineae is promising for fruity beers.
The production of aflatoxin (AF) B1 and B2 was determined during malting of wheat grains artificially contaminated with a toxigenic A. flavus strain (CCDCA 11553) isolated from craft beer raw ...material. Malting was performed in three steps (steeping, germination and kilning) following standard Central European Commission for Brewing Analysis procedures. AFB1 and AFB2 were quantified in eleven samples collected during the three malting steps and in malted wheat. Both, AFB1 and AFB2 were produced at the beginning of steeping and detected in all samples. The levels of AFB1 ranged from 229.35 to 455.66 μg/kg, and from 5.65 to 13.05 μg/kg for AFB2. The AFB2 increased during steeping, while no changes were observed in AFB1. Otherwise, AFB1 decreased during germination and AFB2 did not change. AFB1 and AFB2 increased after 16 h of kilning at 50 °C and decreased at the end of kilning, when the temperature reached 80 °C. The levels of AFB1 wheat malt were lower than those detected in wheat grains during steeping; however, levels of both AFB1 (240.46 μg/kg) and AFB2 (6.36 μg/kg) in Aspergillus flavus inoculated wheat malt exceeded the limits imposed by the regulatory agencies for cereals and derived products.
•Toxigenic Aspergillus flavus was isolated from wheat grains used for craft beer brewing.•A. flavus produced aflatoxins when inoculated into wheat grains during steeping.•Aflatoxins B1 (AFB1) and AFB2 were detected during malting of artificially contaminated wheat.•AFB1 levels in wheat malt obtained from artificially contaminated grains exceeded limits for cereal derived products.
Schooled by the brutalities of totalitarian regimes, the puzzles of sub-atomic physics, the incompatibilities of true believers and the courtrooms of credentialed experts supporting opposing sides ...for pay, we are properly suspicious of claims to accuracy and certainty. The more difficult and more hopeful option is a critical but no less determined revival of the old news rules - aware of the uncertainties and respectful of diverse perspectives, but devoted to enriching understanding rather than defending positions, and willing to let readers make up their own minds.
Non-conventional yeast species have great capacity for producing diverse flavor profiles in production of alcoholic beverages, but their potential for beer brewing, in particular in consecutive ...fermentations with Saccharomyces cerevisiae, has only poorly been explored. We have screened 17 non-conventional yeast species for production of an appealing profile of flavor esters and phenolics in the first phase of alcoholic fermentation, followed by inoculation with S. cerevisiae to complete the fermentation. For measurement of phenolic compounds and their precursors we developed an improved and highly sensitive methodology. The results show that non-conventional yeast species possess promising potential for enhancement of desirable flavors in beer production. Notable examples are increasing isoamyl acetate (fruity, banana flavor) by application of P. kluyverii, augmenting ethyl phenolic compounds (spicy notes) with Brettanomyces species and enhancing 4-vinyl guaiacol (clove-like aroma) with T. delbrueckii. All Pichia strains also produced high levels of ethyl acetate (solvent-like flavor). This might be selectively counteracted by selection of an appropriate S. cerevisiae strain for the second fermentation phase, which lowers total ester profile. Hence, optimization of the process conditions and/or proper strain selection in sequentially inoculated fermentations are required to unlock the full potential for aroma improvement by the non-conventional yeast species.
•Non-Saccharomyces yeasts have been screened for their bioflavoring potential in beer.•Pichia kluyverii is unique for its strong production of fruity esters.•Ethyl and vinyl phenols and their precursors can be determined simultaneously with HPLC.•Brettanomyces sequential inoculation can be positive or negative for flavor profile.•Aroma contribution is not additive in sequential beer fermentations.
The recent realisation regarding the potentiality of the long-neglected non-
Saccharomyces
yeasts in improving the flavour profile and functionality of alcoholic beverages has pushed researchers to ...search for such potent strains in many sources. We studied the fungal diversity and the rice beer production capability of the fungal strains isolated from
emao
—a traditional rice beer starter culture of the Boro community. Fifty distinct colonies were picked from mixed-culture plates, of which ten representative morphotypes were selected for species identification, and simultaneous saccharification and beer fermentation (SSBF) assay. The representative isolates were identified as
Hyphopichia burtonii
(Hbur-FI38, Hbur-FI44, Hbur-FI47 & Hbur-FI68),
Saccharomyces cerevisiae
(Scer-FI51),
Wickerhamomyces anomalus
(Wano-FI52),
Candida carpophila
(Ccar-FI53),
Mucor circinelloides
(Mcir-FI60), and
Saccharomycopsis malanga
(Smal-FI77 and Smal-FI84). The non-
Saccharomyces
yeast strains Hbur-FI38, Hbur-FI44, Ccar-FI53, and Smal-FI77 showed SSBF capacity on rice substrate producing beer that contained 7–10% (v/v) ethanol. A scaled-up fermentation assay was performed to assess the strain-wise fermentation behaviour in large-scale production. The nutritional, functional, and sensory qualities of the SSBF strain fermented beer were compared to the beer produced by
emao.
All the strains produced beer with reduced alcohol and energy value while compared to the traditional starter
emao
. Beer produced by both the strains of
H. burtonii
stood out with higher ascorbic acid, phenol, and antioxidant property, and improved sensory profile in addition to reduced alcohol and energy value. Such SSBF strains are advantageous over the non-SSBF
S. cerevisiae
strains as the former can be used for direct beer production from rice substrates.
Graphical abstract
Juice made from sea-buckthorn berries (Hippophae rhamnoides L.) is a valuable source of bioactive compounds, vitamins, as well as micro- and macronutrients. By applying defatted sea-buckthorn juice, ...it is possible to enhance wheat beer and change its sensory properties and the contents of bioactive compounds in the finished product. A sensory assessment showed that wheat beers with a 5% v/v addition of sea-buckthorn juice were characterised by a balanced taste and aroma (overall impression). Physicochemical analyses showed that, compared to the control samples, wheat beers enhanced with defatted sea-buckthorn juice at a rate of 5% v/v or 10% v/v had high total acidity with respective mean values of 5.30 and 6.88 (0.1 M NaOH/100 mL), energy values lower on average by 4.04% and 8.35%, respective polyphenol contents of 274.1 mg GAE/L and 249.7 mg GAE/L, as well as higher antioxidant activity (measured using DPPH, FRAP, and ABTS assays). The findings show that the samples of wheat beer enhanced with sea-buckthorn juice had average ascorbic acid contents of 2.5 and 4.5 mg/100 mL (in samples with 5% v/v and 10% v/v additions, respectively) and contained flavone glycosides, e.g., kaempferol-3-O-glucuronide-7-O-hexoside. Based on the current findings, it can be concluded that wheat beer enhanced with sea-buckthorn juice could emerge as a new trend in the brewing industry.
Gut microbiota modulation might constitute a mechanism mediating the effects of beer on health. In this randomized, double-blinded, two-arm parallel trial, 22 healthy men were recruited to drink 330 ...mL of nonalcoholic beer (0.0% v/v) or alcoholic beer (5.2% v/v) daily during a 4-week follow-up period. Blood and faecal samples were collected before and after the intervention period. Gut microbiota was analyzed by 16S rRNA gene sequencing. Drinking nonalcoholic or alcoholic beer daily for 4 weeks did not increase body weight and body fat mass and did not changed significantly serum cardiometabolic biomarkers. Nonalcoholic and alcoholic beer increased gut microbiota diversity which has been associated with positive health outcomes and tended to increase faecal alkaline phosphatase activity, a marker of intestinal barrier function. These results suggest the effects of beer on gut microbiota modulation are independent of alcohol and may be mediated by beer polyphenols.
This short communication is devoted to a fully-mechanized flow analysis system for the control of beer fermentation process. The developed system is based on microsolenoid flow controlling devices ...(valves and pumps) and a flow-through optoelectronic detector. All these components are powered and controlled by a Adruino-compatible microprocessor platform that creates an integrated, compact, and robust analytical tool. Multiplication of sample aspiration ports of the analytical system allows for simultaneous monitoring of several independently performed fermentation processes, as well as a single process at the different places of fermentation tank. To demonstrate its practical utility, the developed system has been applied for online and real-time monitoring of yeast propagation and distribution in beer worts in the course of various fermentation processes. Potentially, this flow analysis system can be easily expanded to the form of multianalyte monitor equipped with optoelectronic sensors and biosensors for the determination of other parameters and analytes.
•The real-time monitor of yeast growth in beer wort is presented.•The monitor allows for early detection of irregularities in the fermentation process.•The monitor allows effects of beer wort ingredients on yeast proliferation to be examined.•The monitor allows yeast distribution in wort beer to be controlled.
Craft beer because of its fresh flavor, unique taste, and rich nutrition is becoming more popular to consumers. Compared with industry beer, craft beer is often nonfiltered and nonpasteurized, for ...this reason, it has a short shelf life and is more susceptible to microbial spoilage, which may cause the quality deterioration of craft beer and the formation of biogenic amine as a harmful factor for consumer's health. In this study, the 23 beer‐spoilage bacteria were isolated from craft beer, which were identified as 15 Lactobacillus (L.) brevis, 3 L. plantarum, 1 L. parabuchneri, 2 L. paracasei, and 2 Pediococcus damnosus. Among 23 beer‐spoilage isolates, 20 representatives were able to form tyramine, histamine, putrescine, cadaverine, and/or tryptamine in MRS broth. The nine Lactobacillus strains were incubated in beer and produced tyramine, histamine, putrescine, cadaverine, and/or tryptamine during beer storage process. Logistic and Gompertz model could be adopted to respectively describe the kinetics of microorganism growth and biogenic amine formation. The relationship between the biogenic amines and biomass was simulated by Luedeking–Piret model very well, and showed that the formation of biogenic amine was mainly bacteria growth‐associated in beer. These findings may be helpful for finding the preventive measures to control biogenic amine formation and for enhancing the safety of craft beer.
Practical Application
The selection of the biogenic amine‐producing spoilage bacteria from craft beer and the investigation their kinetics of the growth and biogenic amines production under beer environmental conditions was very helpful for finding preventive measures to eliminate or reduce biogenic amine formation and for appropriate increase in food safety.
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