Molecular weight kinetics and chain scission models for dextran polymers during ultrasonic degradation

Pu, Yuan-Yuan; Zou, Qingsong; Hou, Dianzhi; Zhang, Yiping; Chen, Shan

doi:10.1016/j.carbpol.2016.09.017

Cited by 44 publications

(16 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…A linear polymer chain was found more easily degraded with US than branched ones [22]. The degradation kinetics can be fitted to either a midpoint chain scission model or a random chain scission model [23].…”

Section: Introductionmentioning

confidence: 99%

Effects of Ultrasonication on the Conformational, Microstructural, and Antioxidant Properties of Konjac Glucomannan

Yin

Siu

et al. 2019

Applied Sciences

View full text Add to dashboard Cite

This study aims to evaluate the effects of ultrasonication (US) on the conformational, microstructural, and antioxidant properties of konjac glucomannan (KGM). US treatment with a 20-kHz and 750-W ultrasonic processor at 60% amplitude was applied for partial degradation of KGM with an average molecular weight (MW) of 823.4 kDa. Results indicated that the US treatment caused dramatic reduction in the MW, apparent viscosity, hydrodynamic radius, and z-average mean radius of gyration. The flexibility of chain conformation of native KGM was slightly increased during the US treatment. According to electronic microscopic imaging, the compact, smooth, and orderly fibrous strings formed by KGM were changed to amorphous, porous flakes and globular particles after US treatment. KGM and its US-treated fractions showed moderate radical-scavenging and ferric-reducing antioxidant activity. US degradation of KGM affected these activities either positively or negatively, depending on the US treatment period. In summary, ultrasonic degradation of KGM caused changes in its conformation characteristics, microstructure, and antioxidant activities.

show abstract

Section: Introductionmentioning

confidence: 99%

Effects of Ultrasonication on the Conformational, Microstructural, and Antioxidant Properties of Konjac Glucomannan

Yin

Siu

et al. 2019

Applied Sciences

View full text Add to dashboard Cite

show abstract

“…4. Random depolymerization has been shown, both theoretically and experimentally, to result in a linear increase of (Mw) -1 with time (Malhotra 1986;Pu et al 2017). In a plot of (Mw) -1 versus time (Fig.…”

Section: Composition and Properties Of Extracted Ggm And Mannan Modelmentioning

confidence: 99%

The structure of galactoglucomannan impacts the degradation under alkaline conditions

et al. 2018

View full text Add to dashboard Cite

Galactoglucomannan (GGM) from spruce was studied with respect to the degradation behavior in alkaline solution. Three reference systems including galactomannan from locust bean gum, glucomannan from konjac and the linear water-soluble carboxymethyl cellulose were studied with focus on molecular weight, sugar composition, degradation products, as well as formed oligomers, to identify relative structural changes in GGM. Initially all mannan polysaccharides showed a fast decrease in the molecular weight, which became stable in the later stage. The degradation of the mannan polysaccharides could be described by a function corresponding to the sum of two first order reactions; one slow that was ascribed to peeling, and one fast that was connected with hydrolysis. The galactose side group was stable under conditions used in this study (150 min, 90°C, 0.5 M NaOH). This could suggest that, apart from the covalent connection to C6 in mannose, the galactose substitutions also interact non-covalently with the backbone to stabilize the structure against degradation. Additionally, the combination of different backbone sugars seems to affect the stability of the polysaccharides. For carboxymethyl cellulose the degradation was linear over time which further suggests that the structure and sugar composition play an important role for the alkaline degradation. Molecular dynamics simulations gave details about the conformational behavior of GGM oligomers in water solution, as well as interaction between the oligomers and hydroxide ions.

show abstract

“…Several studies point on increased solubility [23,24] and improved functionality or bioactivity [22,25] of bacterial or plant-based polysaccharides after ultrasonication. These effects were explained by reduced molecular mass and narrow molecular mass distribution accompanied by reduced viscosity [26][27][28][29][30]. However, FT-IR or NMR experiments revealed a mostly unchanged primary structure after shearing [21,31].…”

Section: Introductionmentioning

confidence: 99%

Degradation of Exopolysaccharides from Lactic Acid Bacteria by Thermal, Chemical, Enzymatic and Ultrasound Stresses

Nachtigall

Rohm

Jaros

2021

Foods

View full text Add to dashboard Cite

During isolation, exopolysaccharides (EPS) from lactic acid bacteria are subject of thermal, chemical, enzymatic or ultrasound stress of different intensity that may affect macromolecular properties, for instance molecular mass or (intrinsic) viscosity. These parameters are, however, crucial, as they are associated with the technofunctional potential of EPS replacing commercial thickeners in nonfermented products. The aim of this study was to systematically examine treatments EPS are usually exposed to during isolation and to investigate the underlying degradation mechanisms. Solutions (1.0 g/L) of EPS from Streptococcus thermophilus, isolated as gently as possible, and commercial dextran were analyzed for molecular mass distributions as representative measure of molecule alterations. Generally, acid, excessive heat and ultrasonication, intensified by simultaneous application, showed EPS degradation effects. Thus, recommendations are given for isolation protocols. Ultrasonic degradation at 114 W/cm² fitted into the random chain scission model and followed third- (S. thermophilus EPS) or second-order kinetics (dextran). The degradation rate constant reflects the sensitivity to external stresses and was DGCC7710 EPS > DGCC7919 EPS > dextran > ST143 EPS. Due to their exceptional structural heterogeneity, the differences could not be linked to individual features. The resulting molecular mass showed good correlation (r² = 0.99) with dynamic viscosity.

show abstract

Molecular weight kinetics and chain scission models for dextran polymers during ultrasonic degradation

Cited by 44 publications

References 33 publications

Effects of Ultrasonication on the Conformational, Microstructural, and Antioxidant Properties of Konjac Glucomannan

Effects of Ultrasonication on the Conformational, Microstructural, and Antioxidant Properties of Konjac Glucomannan

The structure of galactoglucomannan impacts the degradation under alkaline conditions

Degradation of Exopolysaccharides from Lactic Acid Bacteria by Thermal, Chemical, Enzymatic and Ultrasound Stresses

Contact Info

Product

Resources

About