Very high gravity brewing can achieve effective energy saving and significant emission reduction, and thereby has been progressively applied in beer industries. However, the yeast cells encountered ...multiple environmental stresses during very high gravity brewing, resulting in the sluggish fermentation. To overcome this issue, a practical strategy, that is increasing the fermentation temperature, has been used. However, to which extent the temperature could be increased and whether the higher temperature would influence the viability and vitality of the cells that would be re-used for the next run of fermentation remains unclear. In this study, we compare the fermentation performance of three lager yeast under different temperatures (11 °C, 15 °C, 18 °C). Yeast cell growth and fermentation rate analysis show that a higher temperature can indeed increase the fermentation rates. However, the taste value and volatile compounds analysis indicated that different temperatures have also changed the flavor fingerprint dramatically. Meanwhile, lower cell viability and flocculation ability could be caused by the higher temperature. Hence, increasing the fermentation temperature in a reasonable range is an available method for coping sluggish problem in very high gravity brewing.
•The impacts of different temperatures on VHG of lager beer was made.•E-tongue and GC-MS were applied to analysis the flavor with lager beer.•Yeast characters were discussed along with the fermentation performance.•Increasing temperature slightly is an available method for sluggish problem.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In this work, we studied the control of Listeria monocytogenes in raw chicken meat by marinating breast strips with beer containing bacteriocin leucocin C. An URA3 auxotrophic strain of probiotic ...yeast Saccharomyces boulardii CNCM I-745 was used as a host to express the gene lecC encoding the bacteriocin leucocin C. Secretion of leucocin C was confirmed by the inhibition against L. monocytogenes using agar well diffusion assay. The new auxotrophic host secreted leucocin C better than previously constructed wild-type strain, and therefore it was used to brew anti-listerial beer. The beer was shown to maintain its anti-listerial activity for 38 days. Chicken breast strips spiked with L. monocytogenes were then marinated with the anti-listerial beer for overnight, and the killing of L. monocytogenes was analysed. Marination with beer containing leucocin C reduced the viable cells of L. monocytogenes by about 1.6 log from (2.2 ± 0.6) × 107 CFU/g on day 24, and 2.2 log from (1.8 ± 0.3) × 105 CFU/g on day 38. In conclusion, the URA3 auxotrophic S. boulardii efficiently secreted the bacteriocin leucocin C, and brewing beer with this strain resulted in anti-listerial beer. Such beer is effective as a marinade in reducing the Listeria risk in chicken breast strips.
•A probiotic yeast S. boulardii that secrets anti-listerial bacteriocin leucocin C was generated.•Leucocin C-secreting S. boulardii was able to brew beer with anti-listerial effects.•The anti-listerial beer was effective to inhibit L. monocytogenes in chicken breast strips.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Putrescine and tryptamine are the main biogenic amines in craft beer.•Total biogenic amines contents in Stout and Porter were the highest.•Biogenic amines contents was increased during ...saccharification and main fermentation.
This study evaluated the levels of eight biogenic amines in 59 craft beers of five styles and monitored the changes during beer fermentation, showing that putrescine and tryptamine were the most abundant at maximum values of 46.14 mg/L and 89.97 mg/L, respectively. This research indicated for the first time that dark beer, such as Stout/Porter, displayed the highest total biogenic amine content due to considerable tryptamine accumulation, with a maximum value of 116.95 mg/L. The total biogenic amine level increased gradually during the segmental saccharification and main fermentation stages, representing the two critical control points for their formation during beer fermentation. This study provides a theoretical basis and technical guidance for the safe and standardized production of craft beer and the formulation of biogenic amines limit standards, which is highly significant for protecting the health of consumers.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Abstract Temperature control in the beer manufacturing process is crucial for product quality. Given the gap between China's automation in beer production and the international level, improving the ...technology in this area has gradually become a core issue in optimizing domestic beer production. This study combines a proportional integral derivative controller with a fuzzy modeling strategy and incorporates a variable‐domain structure to propose a variable‐domain fuzzy proportional integral derivative controller control method. To cope with the challenges of production interaction, the study also introduces neural network technology. The experimental data indicated that the variable‐domain fuzzy proportional integral derivative controller outperforms the conventional proportional integral derivative controller and the fuzzy proportional integral differential controller in terms of overshooting, with a maximum overshoot of only 1.0, compared with 0.50 and 0.70, respectively. The variable‐domain fuzzy proportional integral differential controller exhibited a minimal overshoot of only 0.01 when the model parameter is increased by 20%. In comparison, the other methods reach overshoot values of 0.92 and 1.0. The proposed method maintained superior stability even under the influence of impulse disturbance, step disturbance, and modeling variations. These results demonstrated that the research method is significantly more stable than both the proportion integration differentiation (PID) controller and fuzzy PID controller in complex dynamic parameter environments. The proposed method involved 60 rounds of neural network control, which was successfully implemented. The temperature readings T1 and T2 remained stable within the range of 1.0%–1.02% throughout the experiments. The study demonstrates that the proposed methods have higher accuracy and less fluctuation in actual application, making them more available. Taken together, the above results show that the combination of variable‐domain fuzzy PID controller and neural network technology in beer production has achieved excellent control results. This study not only provides a strong technical support for the progress of beer production technology in China, but also has important industrial application value and wide promotion prospects.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The aim of this study was to evaluate the effect of 15 commercial yeasts in the mitigation of the Fusarium mycotoxins deoxynivalenol (DON) and zearalenone (ZEN) during the brewing process. ...Saccharomyces strains (10 strains of S. cerevisiae and 5 of S. pastorianus) were used to ferment DON and ZEN contaminated wort. Wort samples were taken every 24 h during fermentation, while mycotoxin analysis in yeast was performed at the end of fermentation (96 h); additionally, pH and ethanol content were measured daily. For mycotoxin analysis, after immunoaffinity purification of sample extracts, analysis was performed using an Ultra-High-Pressure Liquid Chromatograph coupled with a diode array or fluorescence detector (UHPLC-DAD/FLD). Mycotoxin presence had no significant effect on the ethanol production during brewing. At the end of fermentation, 10–17% of DON and 30–70% of ZEN had been removed, 6% of the initial concentration of DON and 31% of the ZEN being adsorbed by the yeast. Beermakers must pay careful attention to the raw material since a high percentage of DON could be present at the end of the beer fermentation process. Future studies should focus on the quantification of “masked” mycotoxins that are relevant to food security.
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•After beer fermentation, 83–90% of DON and 30–70% of ZEN in wort was detected.•DON and ZEN adsorption ability of S. pastorianus and S. cerevisiae was evaluated.•Saccharomyces yeasts show higher adsorptions for ZEN than for DON.•DON and ZEN contamination of wort had no effect on ethanol production.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Beer is produced by fermenting cereals with yeast that primarily include ale beer fermented by Saccharomyces cerevisiae or lager beer by S. pastorianus. The strain of Saccharomyces is the critical ...genetic that determines the flavor of beer. Multi-omics of the genome, transcriptome and metabolome of 53 strains of Saccharomyces and an association analysis were performed in this study. A total of 293 flavor substances were identified and 123,426 SNPs from all the strains were selected for GWAS. A total of 441 significant SNPs were associated with 400 genes that are related to 18 flavor substances, and 118 core genes were obtained by WGCNA that used 1147 and 2392 shared differentially expressed genes throughout the whole fermentation process in five ale and four lager strains, respectively. Furthermore, EHT1, BAT1, LEU1 and IRA1 were selected to verify their gene function, and the corresponding flavor substances in beer were significantly altered. Notably, IRA1 is a novel gene related to the synthesis of acids. This study not only helps to understand the synthesis and regulatory mechanism of flavor substances in beer but also provides important genetic clues for their genetic improvement and the creation of novel Saccharomyces varieties to produce new types of beer.
•A total of 293 flavor substances were identified from 53 yeasts.•Lager yeast showed less genetic diversity than ale yeast.•GWAS and WGCNA analysis of beer flavor revealed new metabolic genes and pathways.•IRA1 was a novel gene related to the synthesis of acids.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Yeast flocculation and viability are critical factors in beer production. Adequate flocculation of yeast at the end of fermentation helps to reduce off-flavors and cell separation, while high ...viability is beneficial for yeast reuse. In this study, we used comparative genomics to analyze the genome information on Saccharomyces pastorianus W01, and its spontaneous mutant W02 with appropriate weakened flocculation ability (better off-flavor reduction performance) and unwanted decreased viability, to investigate the effect of different gene expressions on yeast flocculation or/and viability. Our results indicate that knockout of CNE1, CIN5, SIN3, HP-3, YPR170W-B, and SCEPF1_0274000100 and overexpression of CNE1 and ALD2 significantly decreased the flocculation ability of W01, while knockout of EPL1 increased the flocculation ability of W01. Meanwhile, knockout of CIN5, YPR170W-B, OST5, SFT1, SCEPF1_0274000100, and EPL1 and overexpression of SWC3, ALD2, and HP-2 decreased the viability of W01. CIN5, EPL1, SCEPF1_0274000100, ALD2, and YPR170W-B have all been shown to affect yeast flocculation ability and viability.
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IJS, KILJ, NUK, PNG, UL, UM, UPUK
Beer fermentation efficiency improvements have the strongest potential to boost profitability, as its long batch time renders this particular unit operation the throughput bottleneck of this complex, ...multistage biochemical process which mankind has employed for several millennia. Accurate fermentation models are critical for reliable dynamic simulation and process optimisation: empirical trial-and-error approaches are not viable, and incrementally altering proven recipes implies prohibitively expensive campaigns, in terms of equipment use, off-spec production and personnel time for sampling and analysis. This paper considers parameter estimation for a published beer fermentation model, demonstrating that estimating the complete unknown parameter set is an ill-posed problem, which can lead to inconsistent solutions. Systematic sensitivity analysis is pursued, elucidating the relative significance of parametric discrepancy on the validity of key species concentration trajectories. Parameters have been identified and ranked by decreasing importance, and a high-fidelity estimation is performed for a published dataset.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The rapid and efficient consumption of carbon and nitrogen sources by brewer’s yeast is critical for the fermentation process in the brewing industry. The comparison of the growth characterizations ...of typical ale and lager yeast, as well as their consumption preference to carbon and nitrogen sources were investigated in this study. Results showed that the ale strain grew faster and had a more extended stationary phase than the lager strain. However, the lager strain was more tolerant to the stressful environment in the later stage of fermentation. Meanwhile, the ale and lager yeast strains possessed varying preferences for metabolizing the specific fermentable sugar or free amino acid involved in the wort medium. The lager strain had a strong capacity to synthesize the extracellular invertase required for hydrolyzing sucrose as well as a strong capability to metabolize glucose and fructose. Furthermore, the lager strain had an advantage in consuming Lys, Arg, Val, and Phe, whereas the ale strain had a higher assimilation rate in consuming Tyr. These findings provide valuable insights into selecting the appropriate brewer’s yeast strain based on the wort components for the industrial fermentation process.
Key points
• The lager strain is more tolerant to the stressful environment.
• The lager strain has the great capability to synthesize the extracellular invertase.
• The assimilation efficiency of free amino acid varies between ale and lager.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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