Mechanisms of starch digestion by <b>α</b>-amylase—Structural basis for kinetic properties

Dhital, Sushil; Warren, Frederick J.; Butterworth, Peter J.; Ellis, Peter R.; Gidley, Michael J.

doi:10.1080/10408398.2014.922043

Cited by 331 publications

(220 citation statements)

References 188 publications

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“…Heating exposes more starch granules to the action of the enzymes, as described by Dhital et al [24], Martín and López [25], and Pepe et al [32], who suggest that heating the starch in an aqueous suspension increases susceptibility to enzymatic hydrolysis. When the starch suspension is heated, water first enters the amorphous regions, specifically in the hilum, which expands and transmits a disruptive force to the crystalline regions.…”

Section: Enzymatic Hydrolysismentioning

confidence: 87%

“…Scanning electron microscopy images showed a large amount of starch granules embedded in a protein matrix (Figure 1a), which might act as a barrier during the amylolysis of starch granules [23,24]. Martin and Lopez [25] suggest that these granules provide resistance to enzymatic activity, as they are tightly packed by intra-and intermolecular hydrogen bonds in a polycrystalline state, making them resistant to enzymatic treatments.…”

Section: Resultsmentioning

confidence: 99%

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Brosimum Alicastrum as a Novel Starch Source for Bioethanol Production

et al. 2017

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Ramon (Brosimum alicastrum) is a forest tree native to the Mesoamerican region and the Caribbean. The flour obtained from Ramon seeds is 75% carbohydrate, of which 63% is starch, indicating its potential as a novel raw material for bioethanol production. The objective of this study was to produce ethanol from Ramon flour using a 90 • C thermic treatment for 30 min and a native yeast strain (Candida tropicalis) for the fermentation process. In addition, the structure of the flour and the effects of pretreatment were observed via scanning electron microscopy. The native yeast strain was superior to the commercial strain, fermenting 98.8% of the reducing sugar (RS) at 48 h and generating 31% more ethanol than commercial yeast. One ton of flour yielded 213 L of ethanol. These results suggest that Ramon flour is an excellent candidate for ethanol production. This is the first report on bioethanol production using the starch from Ramon seed flour and a native yeast strain isolated from this feedstock. This alternative material for bioethanol production minimizes the competition between food and energy production, a priority for Mexico that has led to significant changes in public policies to enhance the development of renewable energies.

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Section: Enzymatic Hydrolysismentioning

confidence: 87%

Section: Resultsmentioning

confidence: 99%

Brosimum Alicastrum as a Novel Starch Source for Bioethanol Production

et al. 2017

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“…It is also known that the stickiness of food cooked from crops facilitates caries development (Tur and Kraskova 2008: 220). The starch granules of plants are slowly broken down by salivary amylase releasing glucose (Dhital et al 2017) that may be metabolized by the oral bacteria to produce the organic acids. Therefore, cariesogenicity of food cooked from plants is more important than the fact of its prevalence in a diet.…”

Section: Discussionmentioning

confidence: 99%

Frequency of dental caries in children in the Early Iron Age and the Medieval populations from Ukraine

Yanko

Artemyev

Каськова

2017

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In this paper we determine the caries frequency in children of the Early Iron Age (EIA) (the 9th -the 3d centuries BC) and the Medieval populations (the 8th -the beginning of the 15th century AD) from the Ukraine area, and compare the results with the data from several European populations who lived at the same time. The EIA is presented by 41 children skeletons, three of which were Cimmerian (the 9th -the 7th centuries BC) from the territory of contemporary Poltava region; 38 skulls from the territory of contemporary Poltava region and Crimea represented Scythian period (the 7th -the 3d centuries BC). Remains of 24 children from the Medieval populations were also examined, three of which were the ancient Hungarians from the Poltava region (the 8th -the 9th centuries AD), 6 Khazars from the Kharkiv region (the 8th -the 9th centuries), 1 child related the Old Rus culture from the Kyiv region (the 9th century), and 14 representatives of the nomadic populations in the Golden Horde period (the 13th -the beginning of the 15th century) from the Poltava and Zaporizhzhya regions. Taking in consideration the letter archaeobotanical studies we suggest that there were no major changes in the plants exploited during all the studied periods. The frequency of carious lesions in children from the Medieval populations (8.3% in individuals, 0.5% in deciduous teeth, and 0.4% in permanent teeth) is only slightly higher than those from the EIA period (2.4% in individuals and 0.2% in deciduous teeth). These indexes were not larger those of majority of European populations dated to the same historic period. Further isotopic, chemical and palaeobotanical studies of the additional sites, with sufficient sample sizes, allow us to learn so much more of the cariogenic factors in children of the past populations from the Ukraine area.

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“…Another recent critical review has pointed out that processing, such as by milling or cooking, can destroy the physical barrier that attenuates the rate and extent of amylolysis of starch (Dhital, Warren, Butterworth, Ellis & Gidley, 2015). Milling conditions also affected the particle size of the sweet potato flours, which brought in measurable effects of mill type on starch digestibility (Chen & Sopade, 2013).…”

Section: Millingmentioning

confidence: 99%

Mechanism of reduction in starch digestion rate of Durum Wheat by protein

Zou¹

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The aim of the project is to explore the mechanism of durum wheat proteins in slowing starch digestion; this reduction in digestion rate is nutritionally advantageous. The grains of three commercial durum wheat varieties (Jandaroi, Caparoi and Yawa) were employed, from which a range of pasta-derived cooked substrates were prepared: semolina (SE), whole pasta (spaghetti) (WP), powdered pasta (PP) and extracted starch (ST). SE contains inherent protein components; WP has an intact compact structure and gluten network formed by kneading and extruding the SE proteins; PP was ground from WP, thus breaking up the intact compact structure while the gluten network remained intact; and ST was extracted from SE with removal of proteins. To understand how pasta compact structure and proteins influence starch digestion, all these starch-containing samples with different protein composition and structure were subjected to in vitro digestion with various combinations of treatments mimicking gastric conditions with acid and pepsin, before the starch was digested with porcine α-amylase or pancreatin. After plotting the percentage of starch digested vs. time, first-order kinetics characterization through logarithm-of-slope analysis and morphological characterization by confocal microscopy were combined to reveal how the pasta compact structure and gluten network together slow starch digestion rate. Digested samples were collected at different times to characterize the weight distributions of branched starch molecules (wbr (logR h ), R h being hydrodynamic radius) using size-exclusion chromatography (SEC, also termed GPC). These distributions, together with the measured activity of α-amylase in the digestive solution, were used to explore the role that the compact structure and proteins in pasta play in retarding the evolution of starch molecular structure during digestion. Gluten powder (GP) extracted from SE was cooked and centrifuged to separate supernatant from gluten as a pellet, followed by the addition of α-amylase, to characterize to what extent α-amylase interacted with wheat proteins by measuring the activity of α-amylase, to elucidate if the protein components are capable of reducing enzymatic II activity; the analytical technique used was high performance liquid chromatography-mass spectrometry (LC-MS).The results showed that ST and SE were digested following simple first-order kinetics, while WP and PP followed two sequential first-order steps. The rate coefficients for these various steps were altered by pepsin hydrolysis. Confocal microscopy revealed that, following cooking, starch granules were completely swollen for ST, SE and PP samples. In WP, the granules were completely swollen in the external regions, partially swollen in the intermediate region and almost intact in the WP strand center. Gluten entrapment accounts for the sequential kinetic steps in the digestion of pasta starch; the compact microstructure of pasta also reduces digestion rates. A reduced activity of porcine α-amylase and retarded dig...

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Mechanisms of starch digestion by α-amylase—Structural basis for kinetic properties

Cited by 331 publications

References 188 publications

Brosimum Alicastrum as a Novel Starch Source for Bioethanol Production

Brosimum Alicastrum as a Novel Starch Source for Bioethanol Production

Frequency of dental caries in children in the Early Iron Age and the Medieval populations from Ukraine

Mechanism of reduction in starch digestion rate of Durum Wheat by protein

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