Influence of valine and other amino acids on total diacetyl and 2,3-pentanedione levels during fermentation of brewer’s wort

Krogerus, Kristoffer; Gibson, Brian

doi:10.1007/s00253-013-4955-1

Cited by 78 publications

(62 citation statements)

References 43 publications

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“…However, leakage of ␣-acetolactate into the medium results in its nonenzymatic decarboxylation and in the formation of diacetyl. During lagering, yeast cells reduce diacetyl into less-flavor-active substances, such as acetoin (92). A reduction of the time needed for beer maturation may, therefore, significantly shorten the overall brewing time (93).…”

Section: Genetic Strain Improvement Of Lager Yeastmentioning

confidence: 99%

Lager Yeast Comes of Age

Wendland

2014

Eukaryot Cell

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Alcoholic fermentations have accompanied human civilizations throughout our history. Lager yeasts have a several-centurylong tradition of providing fresh beer with clean taste. The yeast strains used for lager beer fermentation have long been recognized as hybrids between two Saccharomyces species. We summarize the initial findings on this hybrid nature, the genomics/ transcriptomics of lager yeasts, and established targets of strain improvements. Next-generation sequencing has provided fast access to yeast genomes. Its use in population genomics has uncovered many more hybridization events within Saccharomyces species, so that lager yeast hybrids are no longer the exception from the rule. These findings have led us to propose network evolution within Saccharomyces species. This "web of life" recognizes the ability of closely related species to exchange DNA and thus drain from a combined gene pool rather than be limited to a gene pool restricted by speciation. Within the domesticated lager yeasts, two groups, the Saaz and Frohberg groups, can be distinguished based on fermentation characteristics. Recent evidence suggests that these groups share an evolutionary history. We thus propose to refer to the Saaz group as Saccharomyces carlsbergensis and to the Frohberg group as Saccharomyces pastorianus based on their distinct genomes. New insight into the hybrid nature of lager yeast will provide novel directions for future strain improvement.

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Section: Genetic Strain Improvement Of Lager Yeastmentioning

confidence: 99%

Lager Yeast Comes of Age

Wendland

2014

Eukaryot Cell

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“…. It has been reported that the amino acid valine and isoleucine are closely related to the synthesis of diacetyl . Perhaps valine was not absorbed in sufficient quantities at the period of feeding the fermentation for yeast growth.…”

Section: Resultsmentioning

confidence: 99%

Fed-batch fermentation with glucose syrup as an adjunct for high-ethanol beer brewing

et al. 2014

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To produce a beer with a high ethanol content, preliminary research on fed-batch fermentation profiles with glucose syrup as an adjunct during the primary fermentation period was conducted. The ethanol concentration of the beer was elevated by feeding a glucose syrup into the fermentors at a later stage of primary fermentation. Fermentation trials were carried out using a typical lager strain, SC-9, with a pitching rate at 7.0 × 10 6 cells/mL. An all-malt wort (12.5°P) was employed and the primary fermentation temperature was 14°C. Glucose syrup was supplemented when the concentration of residual reducing sugars was decreased to~10 g/L. Results showed that the supplemented glucose was consumed rapidly and that the ethanol concentration in the final beer was raised to 67.9 g/L. Additional growth of yeast was observed after feeding accompanied by a low yield of ethanol (~0.46 g/g). Formation of diacetyl was enhanced by yeast growth and two additional peaks were obtained after feeding. The peak value of the diacetyl concentration was 1.90 mg/L. The fed-batch fermentation resulted in a beer with an overproduction of higher alcohols and esters, indicating that brewing under these experimental conditions led to an unbalanced flavour profile. Results of optimization demonstrated that the optimal conditions were found to be 15°P for initial wort extract, 10°C for fermentation temperature and 20 × 10 6 cells/mL for yeast pitching rate, leading to total higher alcohols of 173.8 mg/L, total esters of 22.8 mg/L and an acetaldehyde concentration of 40.5 mg/L. A 12 day maturation and fermentation temperature of 8°C was needed to reduce the acetaldehyde to 14.3 mg/L.

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“…The positive contribution of buttery flavour to certain beer styles can be regulated through diacetyl formation, because diacetyl has a relatively lower detection threshold. Diacetyl is a by‐product of beer fermentation by Saccharomyces yeast and arises from the spontaneous nonenzymatic oxidative decarboxylation of α‐acetolactic acid, which is an intermediate in the valine biosynthesis pathway (Stahl et al ., ; Krogerus & Gibson, ,b; Fig. ).…”

Section: Novel‐flavoured Beersmentioning

confidence: 94%

An overview of selected specialty beers: developments, challenges and prospects

Yeo

Liu

2014

Int J of Food Sci Tech

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The brewing industry has devoted much research effort into the development of new technologies and innovations for the expansion of the assortment of specialty beers in response to increased consumer demand. Specialty beers are more or less the catch-all for beer styles, which do not fit into conventional beer categories and five types of specialty beers are of particular interest -low-calorie beer, low-alcohol or nonalcohol beer, novel-flavoured beer, gluten-free beer and functional beer. The selected beer types are technologically challenging to produce relative to the traditional approach of ingredient addition, yet offer special appeal to consumers from the perspective of health and flavour. Biological processes that make use of the equipment of a traditional brewery plant should be better exploited in comparison with nonbiological technologies such as thermal and membrane processes. Probiotic beer could be the specialty beer of the future in light of the increasing popularity of probiotics. These beers are reviewed in terms of developments, challenges and prospects.

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Influence of valine and other amino acids on total diacetyl and 2,3-pentanedione levels during fermentation of brewer’s wort

Cited by 78 publications

References 43 publications

Lager Yeast Comes of Age

Lager Yeast Comes of Age

Fed-batch fermentation with glucose syrup as an adjunct for high-ethanol beer brewing

An overview of selected specialty beers: developments, challenges and prospects

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