Patterns of Modification in Malting Barley

Briggs, D. E.; MacDonald, Joanne E.

doi:10.1002/j.2050-0416.1983.tb04184.x

Cited by 36 publications

(10 citation statements)

References 39 publications

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“…1. Germination on moist paper can have a different progression (Briggs and MacDonald 1983;MacGregor et al 1994), possibly because of uneven exposition to water and oxygen.…”

Section: B-glucan Breakdown During Maltingmentioning

confidence: 99%

“…As the relative contributions of b-glucanase by the scutellum and the aleurone layer differ among grains, the actual pattern of modification is highly variable. Based on Gibbons (1980), Briggs and MacDonald (1983), Selvig et al (1986), Oh and Briggs (1989), Fincher (1989), and Briggs (1998). The growth of shoot and rootlets is not shown for the sake of simplicity substrate), which can be described with the MichaelisMenten reaction mechanism .…”

Section: B-glucan Breakdown During Maltingmentioning

confidence: 99%

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A theoretical framework for β-glucan degradation during barley malting

Gianinetti¹

2009

Theory Biosci.

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During malting, barley germinates and produces hydrolytic enzymes that de-structure the endosperm, making the grains soft and friable. This process starts close to the embryo and spreads throughout the whole grain. It is leaded by the degradation of cell walls, which are mainly constituted of beta-glucans. Fast and extended breakdown of beta-glucans occurs by means of an expanding reaction front driven by beta-glucanase, and appears to follow pseudo-first-order kinetics. Endosperm permeabilization to macromolecules is closely linked to the dismantling of cell walls, thus that access to beta-glucans by beta-glucanase itself is limited. It is shown that the kinetics of beta-glucan degradation during malting are consequent to this condition, and can be explained according to an anomalous evolution of the reverse quasi-steady-state approximation (rQSSA) for enzymatic reactions. In fact, kinetics based on the rQSSA include a transient phase wherein fast substrate depletion is indeed of pseudo-first-order. In the germinating barley, the conditions in which the physical modification of the endosperm occurs are shown to be suitable for the fast transient to persist in dynamic equilibrium while it progressively expands throughout the grain, depleting most beta-glucans and, then, establishing the overall kinetics of beta-glucan breakdown.

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“…1. Germination on moist paper can have a different progression (Briggs and MacDonald 1983;MacGregor et al 1994), possibly because of uneven exposition to water and oxygen.…”

Section: B-glucan Breakdown During Maltingmentioning

confidence: 99%

Section: B-glucan Breakdown During Maltingmentioning

confidence: 99%

A theoretical framework for β-glucan degradation during barley malting

Gianinetti¹

2009

Theory Biosci.

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“…Direct determination of P-glucan may be of more value in assessing malt quality than indirect techniques based upon assessing modification of stained grains. 1 …”

Section: Introductionmentioning

confidence: 99%

Changes in β‐glucan and other carbohydrate components of barley during malting

Henry

1988

J Sci Food Agric

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A BS TRA CTChanges in total (1+3), (1+4)-P-glucan content were followed during the micro-malting of nine varieties of barley with a wide range of malting qualities. These changes were related to estimates of endosperm modification based upon staining with Calcofluor. P-Glucan content declined from an average of 3.54% in the barley to 0.75% in the malt. Pentosan and total starch (including starch-derived oligosaccharides) levels showed comparatively little change during malting. /3-Glucan composition of the barley was a poor indicator of malting performance. However, the P-glucan, starch and xylose contents of the malt all showed significant correlations with malt extract. Estimation of malt P-glucan content gave the best indication of malt quality. Direct determination of P-glucan may be of more value in assessing malt quality than indirect techniques based upon assessing modification of stained grains.

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“…We remark that other experimentalists have reported other patterns of modification (e.g. Briggs & MacDonald 1983or Palmer 1983) and these have been discussed elsewhere (O'Brien & Fowkes 2005). Here, our interest is rather with a determination of the front speed and structure in terms of basic physical and chemical parameters.…”

Section: Introductionmentioning

confidence: 73%

The application of enzyme reaction, nonlinear diffusion models to the malting process

Fowkes

O’Brien²

2009

Proc. R. Soc. A.

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We extend the classic Michaelis-Menten kinetics model of the enzyme-mediated conversion of substrate to product to situations in which the enzymes need to diffuse through the underlying structure to reach unconverted substrate and in which the diffusivity is greatly increased by the conversion. The work was prompted by the study of the germination and modification of barley grain that occurs during malting, but is broadly applicable. A nonlinear diffusion, enzyme reaction model of the modification process is proposed and some accurate approximate analytic solutions are derived. We find that a sharp modification front is set up between the modified and the unmodified regions of the barley grain. This front propagates with an almost constant speed through the medium and our findings are consistent with the available experimental observations.

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Patterns of Modification in Malting Barley

Cited by 36 publications

References 39 publications

A theoretical framework for β-glucan degradation during barley malting

A theoretical framework for β-glucan degradation during barley malting

Changes in β‐glucan and other carbohydrate components of barley during malting

The application of enzyme reaction, nonlinear diffusion models to the malting process

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