Model for the influence of mass transport on enzymatic hydrolysis of polysaccharides

Heitmann, T.; Wenzig, Edda; Mersmann, Alfons

doi:10.1002/ceat.270200102

Cited by 3 publications

(4 citation statements)

References 23 publications

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“…Native starch has a limited quantity of digestible material and so a relatively high total starch concentration is needed in order to provide enough substrate to reach an activity of Vmax/2; however, as the amount of available starch increase greatly after the gelatinization, the total amount of starch needed to reach Vmax/2 decreases, causing an apparently decreased Km (Baldwin et al, 2015). The similar results can also be seen elsewhere (Heitmann, Wenzig & Mersmann, 1997). It is also noted that in a certain limit, Michaelis-Menten kinetics reduce to simple first order.…”

Section: Kinetics Of Starch Digestibilitysupporting

confidence: 73%

“…Molecules with higher molecular weights decrease the accessibility of the starch towards active centres of the enzymes, due to an increase in steric hindrance. It has been studied that the in the Michaellis-Menten equation is affected by the degree of polymerisation and the ratio of α-(1→6) branching bonds of starch (Heitmann et al, 1997). It is also noted that starch molecular structure has a significant effect , e.g.…”

Section: Kinetics Of Starch Digestibilitymentioning

confidence: 99%

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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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Section: Kinetics Of Starch Digestibilitysupporting

confidence: 73%

Section: Kinetics Of Starch Digestibilitymentioning

confidence: 99%

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

Zou¹

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“…The timing for reading considered t ϭ 0 as the time when enzyme was added to the substrate. The starch concentration was considered to be not limiting for the amylolytic reaction since the reported K m values for starch of many amylases are within a range of 0.35 to 4.7 mg/ml [16,17].…”

Section: Viscometric Assaymentioning

confidence: 99%

A critical assessment of a viscometric assay for measuring Saccharomycopsis fibuligera α-amylase activity on gelatinised cassava starch

González

Fariña

Figueroa

2002

Enzyme and Microbial Technology

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“…These materials generally contain 75-80 % of cellulose and hemicellulose, which are not easily converted to simple monomeric sugars due to their recalcitrant nature [1][2][3]. However, hemicellulose and cellulose may be converted to fermentable sugars in the presence of dilute acid or cellulase [4,5]. Compared to acid hydrolysis, enzymatic hydrolysis is milder and more specific, but it requires pretreatment to improve the enzymatic digestibility.…”

Section: Introductionmentioning

confidence: 99%

Enzymatic Hydrolysis of Corn Stover after Pretreatment with Dilute Sulfuric Acid

et al. 2007

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Although many previous studies have been carried on the enzymatic hydrolysis of corn stover after pretreatment with dilute sulfuric acid, this paper emphasizes the use of different conditions to attain the highest yields of two sugars, xylose and glucose, from both stages. The pretreatment was performed at a range of sulfuric acid concentrations of 2, 4 and 6 % at 80, 100 and 120°C. Up to 77 % xylose yield was obtained while the glucose yield was only 8.4 %. The corresponding solid phase was hydrolyzed by cellulase and the influences of five factors and their interactions on enzyme hydrolysis were evaluated by response surface methodology based on one-factor-at-a-time experiments. The optimal levels for each variable to obtain the highest reducing sugar yield were as follows: enzyme concentration of 22 FPU/g substrate, substrate concentration of 77 g/L, temperature of 49°C, pH 4.8 and reaction time of 38 h. A reducing sugar yield of 42.11 g/100 g substrate was achieved, which was consistent with the predicted value of 42.13 g/ 100 g substrate. Compared with the one-factor-at-a-time experiments, there was a 9.4 % increase in reducing sugar yield when the enzyme concentration was decreased to 3 FPU/g substrate, the substrate concentration increased to 17 g/L and the reaction time dropped to 22 h. The total sugar released from the two stages was 62.81 g/100 g substrate.

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Model for the influence of mass transport on enzymatic hydrolysis of polysaccharides

Cited by 3 publications

References 23 publications

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

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

A critical assessment of a viscometric assay for measuring Saccharomycopsis fibuligera α-amylase activity on gelatinised cassava starch

Enzymatic Hydrolysis of Corn Stover after Pretreatment with Dilute Sulfuric Acid

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