Investigating the Mechanisms of Amylolysis of Starch Granules by Solution-State NMR

Baldwin, Andrew J.; Egan, Danielle L.; Warren, Frederick J.; Barker, Paul D.; Dobson, Christopher M.; Butterworth, Peter J.; Ellis, Peter R.

doi:10.1021/acs.biomac.5b00190

Cited by 49 publications

(40 citation statements)

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“…However, considering the intrinsic heterogeneity of individual starch granules and the even larger differences observed among granules of different botanical sources, the mechanisms of hydrolysis by -amylase deserve more detailed investigation, given the important physiological implications of starch digestion. 7 Starches are classified according to the amylose/amylopectin ratio: those starches with 25-30% amylose and 70-75% amylopectin are usually named 'normal' starches; some starches present high amylopectin levels (98-99 %) and are called 'waxy' starches; a third group includes starches with high amylose content (50-70%), e.g. Hylon ® maize starches.…”

Section: Starch Overviewmentioning

confidence: 99%

Starch digestibility: past, present, and future

et al. 2018

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In the last century, starch present in foods was considered to be completely digested. However, during the 1980s, studies on starch digestion started to show that besides digestible starch, which could be rapidly or slowly hydrolysed, there was a variable fraction that resisted hydrolysis by digestive enzymes. That fraction was named resistant starch (RS) and it encompasses those forms of starch that are not accessible to human digestive enzymes but can be fermented by the colonic microbiota, producing short-chain fatty acids. RS has been classified into five types, depending on the mechanism governing its resistance to enzymatic hydrolysis. Early research on RS was focused on the methods to determine its content in foods and its physiological effects, including fermentability in the large intestine. Later on, due to the interest of the food industry, methods to increase the RS content of isolated starches were developed. Nowadays, the influence of RS on the gut microbiota is a relevant research topic owing to its potential health-related benefits. This review summarizes over 30 years of investigation on starch digestibility, its relationship with human health, the methods to produce RS and its impact on the microbiome. © 2018 Society of Chemical Industry.

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Section: Starch Overviewmentioning

confidence: 99%

Starch digestibility: past, present, and future

et al. 2018

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“…[1][2][3][4][5][6][7] The transition of starch from its native, semi-crystalline, granular form to an amorphous form through hydrothermal processing (cooking) results in a dramatic increase in susceptibility to a-amylase digestion. The percentage helical order or crystallinity of starches is recognized as contributing to signature properties such as the integrity of granules, the mechanical properties of processed starches, and amylase digestibility.…”

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Rapid quantification of starch molecular order through multivariate modelling of¹³C CP/MAS NMR spectra

2015

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“…The increase of maltose content by the addition of rice adjuncts: During the pre-gelatinisation of rice starch, starch molecules would have leached out from inside granules, leading to the production of more rapidly degraded materials. These have starch chains exposed to the solution and so are readily available for attack by amylase [33,34]. Based on this, during mashing, the increase of those rapidly degraded materials would be easily degraded by both αand β-amylase, leading to an increase of maltose content following the addition of rice adjunct.…”

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Effects of the Starch Molecular Structures in Barley Malts and Rice Adjuncts on Brewing Performance

Quek

et al. 2018

Fermentation

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Background: Achieving optimal fermentation is challenging when the variation within malt starch structure and enzyme activities are not part of the standard malting specifications. This study explores how the variation of starch and starch amylolytic enzymes in both malts and rice adjuncts affect the mashing and the subsequent yeast fermentation in the laboratory-scale production of beer. Results: The addition of rice adjuncts significantly increased the maltose content whilst reducing the glucose content during mashing. The maltotriose content, released during mashing, was significantly negatively correlated with the total amylose content (r = −0.64, p < 0.05), and significantly negatively correlated with the number of amylopectin longer chains (degree of polymerization 37-100) (r = −0.75, p < 0.01). During fermentation, while the content of maltotriose significantly and positively correlated with both the rate and amount of ethanol production (r = 0.70, p < 0.05; r = 0.70, p < 0.05, respectively), the content of soluble nitrogen in the wort was significantly and positively correlated with both the rate and the amount of ethanol production (r = 0.63, p< 0.05; r = 0.62, p < 0.05, respectively). The amount of amylopectin with longer chains was; however, significantly negatively correlated with the ethanol production (r = −0.06, p < 0.05). Small variations among the ethanol concentration and the rate of ethanol production during fermentation were found with the addition of different rice varieties. Conclusions: The effects of the rice adjuncts on the performance of fermentation depends on the properties of the malt, including the protein modification and malt enzyme activities. This study provides data to improve standard malt specifications in order for brewers to acquire more efficient fermentation, and includes useful molecular structural characterisation.Fermentation 2018, 4, 103 2 of 21 diastase enzymes in producing fermentable sugars from malt, as well as malt and solid adjuncts [7][8][9][10][11][12]. However, none of the latter studies investigated the main substrate responsible for the fermentation: starch. One recent study examined the variation of starch structures between malts (and rice adjuncts), and also the starch-degrading enzymes and the resultant fermentable sugars [13]. However, no studies have considered any variations in starch quality, its role in the production of fermentable sugars and its fermentation efficiency. Except for the effects of starch structure, other factors are also involved in altering the release of fermentable sugars. For example, the protein content and the activities of amylolytic enzymes within the barley samples used can affect the release of fermentable sugars during mashing.Starch in barley, like most cereals, is the most abundant component within the grain, but the amount and composition varies depending upon grain type, as well as variety, and the environment the crop was grown in [14][15][16][17]. Starch is a complex branched glucose polymer that is comprised of amy...

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Investigating the Mechanisms of Amylolysis of Starch Granules by Solution-State NMR

Cited by 49 publications

References 46 publications

Starch digestibility: past, present, and future

Starch digestibility: past, present, and future

Rapid quantification of starch molecular order through multivariate modelling of¹³C CP/MAS NMR spectra

Effects of the Starch Molecular Structures in Barley Malts and Rice Adjuncts on Brewing Performance

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Investigating the Mechanisms of Amylolysis of Starch Granules by Solution-State NMR

Cited by 49 publications

References 46 publications

Starch digestibility: past, present, and future

Starch digestibility: past, present, and future

Rapid quantification of starch molecular order through multivariate modelling of13C CP/MAS NMR spectra

Effects of the Starch Molecular Structures in Barley Malts and Rice Adjuncts on Brewing Performance

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Rapid quantification of starch molecular order through multivariate modelling of¹³C CP/MAS NMR spectra