Chelators and Metal Buffering in Fermentation

Jacobsen, T.; Wathne, B.; Lie, S.

doi:10.1002/j.2050-0416.1977.tb06806.x

Cited by 6 publications

(2 citation statements)

References 11 publications

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“…Thus, to estimate the real amount of ions removed from the wort, both the mass of spent grains and their concentration of Mg 2+ were taken into account. In the presented work, the nitrogen compounds and polyphenols in the raw materials and wort were not determined, but for future research it is suggested that there should be a focus on these compounds as well, owing to their chelating properties (32). Generally, wheat contains more proteins than barley (15), and barley malt proteolytic enzymes solubilize and partially degrade wheat proteins (33).…”

Section: Magnesium Ionsmentioning

confidence: 99%

Effect of wheat malt on the concentration of metal ions in wort and brewhouse by-products

et al. 2015

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The ionic composition of brewer's wort depends on the raw materials and processing employed. The macroelement content is usually sufficient for yeast, but some of the microelements (mainly zinc) often need to be supplemented to the wort. Wheat malt is used as an adjunct in the production of beer, replacing up to 60% of barley malt. In this study, the effect of replacing barley malt with wheat malt on the concentration of magnesium, manganese, iron and zinc ions in brewer's wort was investigated. The ionic content of both the raw materials and by-products were analysed. Similar amounts of magnesium ions were found in wheat malt and barley malt, whereas, manganese, zinc and iron were more abundant in the wheat malt. Nevertheless, wheat malt did not cause a significant change in ion concentration in the first wort (except for magnesium; its content decreased). The ionic content in the spent grains increased owing to wheat malt addition; the concentration of ions in the wort decreased after wort boiling (Mn 2+ and Fe) or remained unaffected (Mg 2+ and Zn 2+). It was concluded that the ionic composition of the wort depends mainly on the removal rate of ions from the wort during mash filtration and hot trub separation, rather than on the actual amount of ions in the raw materials.

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Section: Magnesium Ionsmentioning

confidence: 99%

Effect of wheat malt on the concentration of metal ions in wort and brewhouse by-products

et al. 2015

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“…Industrial feedstocks contain a multitude of soluble chelating and insoluble adsorbing materials that act as sinks to reduce the bioavailability of metal ions (Jones and Greenfield, 1984). This has been addressed for brewing fermentations by Jacobsen et al (1977). Because of the difficulties in differentiating between free and bound metal ion concentrations in complex media, optimization of "available" Mg2+ levels in fermentations would be problematic but, nevertheless, worthwhile.…”

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confidence: 99%

The Roles of Magnesium in Biotechnology

Walker

1994

Critical Reviews in Biotechnology

116

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This review highlights the important roles played by magnesium in the growth and metabolic functions of microbial and animal cells, and therefore assigns a key role for magnesium ions in biotechnology. The fundamental biochemical and physiological actions of magnesium as a regulatory cation are outlined. Such actions are deemed to be relevant in an applied sense, because Mg2+ availability in cell culture and fermentation media can dramatically influence growth and metabolism of cells. Manipulation of extracellular and intracellular magnesium ions can thus be envisaged as a relatively simplistic, but nevertheless versatile, means of physiological cell engineering. In addition, biological antagonism between calcium and magnesium at the molecular level may have profound consequences for the optimization of biotechnological processes that exploit cells. In fermentation, for example, it is argued that the efficiency of microbial conversion of substrate to product may be improved by altering Mg:Ca concentration ratios in industrial feedstocks in a way that makes more magnesium available to the cells. With particular respect to yeast-based biotechnologies, magnesium availability is seen as being crucially important in governing central pathways of carbohydrate catabolism, especially ethanolic fermentation. It is proposed that such influences of magnesium ions are expressed at the combined levels of key enzyme activation and cell membrane stabilization. The former ensures optimum flow of substrate to ethanol and the latter acts to protect yeasts from physical and chemical stress.

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The influence of metal ions on concentrations of flavour‐active sulphur compounds measured in beer using dynamic headspace sampling

Walker¹

1995

J Sci Food Agric

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Addition of copper(I1) ions (< 1.6mglitre-I) to beer significantly reduced (P < 0.05) concentrations of hydrogen sulphide and ethanethiol measured in beer, but had no effect on methyl sulphide, methyl thioacetate and methyl disulphide. Zinc, iron(III), manganese(II), nickel, lead(I1) and tin(I1) ions, at similar concentrations, had no effect on any of the sulphur volatiles. When metal ions were added at a concentration of 1 glitre-' zinc, iron(II1) and lead(I1) reversibly bound hydrogen sulphide and enthanethiol.

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Chelators and Metal Buffering in Fermentation

Cited by 6 publications

References 11 publications

Effect of wheat malt on the concentration of metal ions in wort and brewhouse by-products

Effect of wheat malt on the concentration of metal ions in wort and brewhouse by-products

The Roles of Magnesium in Biotechnology

The influence of metal ions on concentrations of flavour‐active sulphur compounds measured in beer using dynamic headspace sampling

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