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Vegemite Beer: yeast extract spreads as nutrient supplements to promote fermentation.

ABSTRACT: Vegemite is an iconic Australian food spread made from spent brewers' yeast extract, which has been reported to be used as an ingredient in illegal home brewing. In this study, we tested the utility of Vegemite and the similar spread Marmite in promoting fermentation. We could not culture microorganisms from either Vegemite or Marmite, consistent with these food-grade spreads being essentially sterile. To test if the addition of Vegemite or Marmite could assist in fermentation when additional viable yeast was also present, solutions containing glucose and a range of concentrations of either Vegemite or Marmite were inoculated with brewers' yeast. No fermentation occurred in any condition without addition of extra brewer's yeast. Fermentation did not occur when yeast was inoculated into solutions containing only glucose, but progressed efficiently with when Vegemite or Marmite was also added. Gas Chromatography confirmed that ethanol was present at ?3% v/v post-fermentation in all samples which contained glucose, Vegemite or Marmite, and brewers' yeast. Trace amounts of methanol were also detected. Mass spectrometry proteomics identified abundant intracellular yeast proteins and barley proteins in Vegemite and Marmite, and abundant secreted yeast proteins from actively growing yeast in those samples to which extra brewers' yeast had been added. We estimate that the real-world cost of home brewed "Vegemite Beer" would be very low. Our results show that Vegemite or other yeast extract spreads could provide cheap and readily available sources of nutrient supplementation to increase the efficiency of fermentation in home brewing or other settings.

SUBMITTER: Kerr ED

PROVIDER: S-EPMC4991886 | biostudies-literature | 2016

REPOSITORIES: biostudies-literature

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Vegemite Beer: yeast extract spreads as nutrient supplements to promote fermentation.

Kerr Edward D ED Schulz Benjamin L BL

PeerJ 20160810

Vegemite is an iconic Australian food spread made from spent brewers' yeast extract, which has been reported to be used as an ingredient in illegal home brewing. In this study, we tested the utility of Vegemite and the similar spread Marmite in promoting fermentation. We could not culture microorganisms from either Vegemite or Marmite, consistent with these food-grade spreads being essentially sterile. To test if the addition of Vegemite or Marmite could assist in fermentation when additional vi ...[more]

PMID: 27602264

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Project description:BackgroundYeast extract spreads and tomato-based sauces (i.e., ketchup) are consumed regularly by the Australian population. Therefore, there is a need to explore the contribution of these condiments to nutrient intakes among Australians.MethodsThe present study comprises a secondary analysis of data from the 2011-2012 Australian National Nutrition and Physical Activity Survey. Dietary intake data were undertaken for 12,153 Australians aged ≥ 2 years, using 24-h recalls. Yeast extract spreads and tomato-based sauces were categorised based on how they were defined in the Australian Food and Nutrient (AUSNUT) 2011-2013 database. Kruskal-Wallis H tests and the post-hoc Dunn's test with Bonferroni correction were applied to test whether a significant difference existed in the percentage contribution of yeast extract spreads and tomato-based sauces to intakes of select nutrients.ResultsIn total, 19.6% (n = 2384) of the population sample consumed yeast extract spreads and/or tomato-based sauces during the 24-h recall. The percentage contribution of yeast extract spreads to daily intakes of sodium, potassium, thiamine, riboflavin, niacin, folate, magnesium, iron, zinc and iodine were significantly higher in line with a greater quantity of yeast extract spread consumed (p < 0.05). The percentage contribution of tomato-based sauces to daily intakes of sodium, potassium, riboflavin, niacin, folate, beta-carotene, magnesium, iron, zinc and iodine was increased significantly with a greater quantity of tomato-based sauces consumed (p < 0.05).ConclusionsConsumption of yeast extracts and tomato-based sauces contribute to greater intake of key nutrients, such as B-vitamins and beta-carotene, and may assist in meeting key nutrient reference values. However, consumption of these sauces and condiments also resulted in greater intakes of sodium, contributing to population intakes exceeding recommendations. Reducing sodium content of frequently consumed condiments may potentially assist in lowering population intakes, at the same time as preserving intakes of other important nutrients.

Project description:During beer production, yeast generate ethanol that is exported to the extracellular environment where it accumulates. Depending on the initial carbohydrate concentration in the wort, the amount of yeast biomass inoculated, the fermentation temperature, and the yeast attenuation capacity, a high concentration of ethanol can be achieved in beer. The increase in ethanol concentration as a consequence of the fermentation of high gravity (HG) or very high gravity (VHG) worts promotes deleterious pleiotropic effects on the yeast cells. Moderate concentrations of ethanol (5% v/v) change the enzymatic kinetics of proteins and affect biological processes, such as the cell cycle and metabolism, impacting the reuse of yeast for subsequent fermentation. However, high concentrations of ethanol (> 5% v/v) dramatically alter protein structure, leading to unfolded proteins as well as amorphous protein aggregates. It is noteworthy that the effects of elevated ethanol concentrations generated during beer fermentation resemble those of heat shock stress, with similar responses observed in both situations, such as the activation of proteostasis and protein quality control mechanisms in different cell compartments, including endoplasmic reticulum (ER), mitochondria, and cytosol. Despite the extensive published molecular and biochemical data regarding the roles of proteostasis in different organelles of yeast cells, little is known about how this mechanism impacts beer fermentation and how different proteostasis mechanisms found in ER, mitochondria, and cytosol communicate with each other during ethanol/fermentative stress. Supporting this integrative view, transcriptome data analysis was applied using publicly available information for a lager yeast strain grown under beer production conditions. The transcriptome data indicated upregulation of genes that encode chaperones, co-chaperones, unfolded protein response elements in ER and mitochondria, ubiquitin ligases, proteasome components, N-glycosylation quality control pathway proteins, and components of processing bodies (p-bodies) and stress granules (SGs) during lager beer fermentation. Thus, the main purpose of this hypothesis and theory manuscript is to provide a concise picture of how inter-organellar proteostasis mechanisms are connected with one another and with biological processes that may modulate the viability and/or vitality of yeast populations during HG/VHG beer fermentation and serial repitching.

Dataset Information

Vegemite Beer: yeast extract spreads as nutrient supplements to promote fermentation.

Publications

Vegemite Beer: yeast extract spreads as nutrient supplements to promote fermentation.

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