Characterization Methods for Starch-Based Materials: State of the Art and Perspectives

Wu, Alex; Witt, Torsten; Gilbert, Robert G.

doi:10.1071/ch13397

Cited by 60 publications

(21 citation statements)

References 131 publications

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“…It is noted that the complete chain-length distribution can be used to calculate the degree of branching through the formula (Wu et al 2013b): DB ¼ P X N de ðXÞ P X XN de ðXÞ , which is an exact result arising from the definition of the degree of branching and so this quantity is not an independent structural variable, given a complete parameterization of the CLD, as done here. However, it is a useful and commonly used property, so correlations with the independent structural are listed here.…”

Section: Correlations Between Parameters For Amylopectin and Amylosementioning

confidence: 99%

Competition between Granule Bound Starch Synthase and Starch Branching Enzyme in Starch Biosynthesis

Han

Yang

Zhu

et al. 2019

Rice

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Background: Starch branching enzymes (SBE) and granule-bound starch synthase (GBSS) are two important enzymes for starch biosynthesis. SBE mainly contributes to the formation of side branches, and GBSS mainly contributes for the synthesis of amylose molecules. However, there are still gaps in the understanding of possible interactions between SBE and GBSS. Results: Nineteen natural rice varieties with amylose contents up to 28% were used. The molecular structure, in the form of the chain-length distribution (CLDs, the distribution of the number of monomer units in each branch) was measured after enzymatic debranching, using fluorophore-assisted carbohydrate electrophoresis for amylopectin and size-exclusion chromatography for amylose. The resulting distributions were fitted to two mathematical models based on the underlying biosynthetic processes, which express the CLDs in terms of parameters reflecting relevant enzyme activities. Conclusions: Finding statistically valid correlations between the values of these parameters showed that GBSSI and SBEI compete for substrates during rice starch biosynthesis, and synthesis of amylose short chains involves several enzymes including GBSSI, SBE and SSS (soluble starch synthase). Since the amylose CLD is important for a number of functional properties such as digestion rate, this knowledge is potentially useful for developing varieties with improved functional properties.

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Section: Correlations Between Parameters For Amylopectin and Amylosementioning

confidence: 99%

Competition between Granule Bound Starch Synthase and Starch Branching Enzyme in Starch Biosynthesis

Han

Yang

Zhu

et al. 2019

Rice

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“…These two macromolecules are the basis of the aggregation and granule structure of starch and provide an excellent conceptual approach to the understanding of the structure-processing-property relationships of natural polymers (P erez & Bertoft, 2010;Wu, Witt, & Gilbert, 2013;Liao et al, 2014). Amylose is a linear molecular with a few long branches, whereas amylopectin is highly branched, containing~5% branching points and a large number of short branches (Damager, Engelsen, Blennow, Lindberg Møller, & Motawia, 2010).…”

Section: Introductionmentioning

confidence: 99%

Shear degradation of corn starches with different amylose contents

et al. 2017

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a b s t r a c tThis work investigated the effect of shear on the starch degradation, with a particular focus on the changes in molecular and lamellar structures. Corn starches with different amylose/amylopectin ratios (waxy corn starch, or WCS: 1:99; normal corn starch, or NCS: 25:75; and Gelose 80 starch, or G80: 80:20) were used as model materials to be processed using a Haake twin-rotor mixer for different times. Molecular and lamellar structural analysis was performed using size-exclusion chromatography (SEC) and small-angle X-ray scattering (SAXS). The degree of damage of starch at the granule level was evaluated by an assay kit. The results showed that amylose molecules in starch granules did not change significantly, while amylopectin molecules degraded to a stable size caused by the shear treatment. The average thickness of semi-crystalline lamellae disappeared rapidly during processing. A typical positive deviation from Porod's law at a high q region was observed, attributed to the presence of thermal density fluctuations or mixing within phases. Nonetheless, the degree of mixing within phases for the processed samples was lower than the native starch. The study of the mass fractal structure indicated that the scattering objects of the processed starches were more compact than those of the native counterparts. Furthermore, waxy corn starch (containing mostly amylopectin) experienced the greatest granule damage than the other starches. All the results showed that the rigid crystal structure in amylopectin is more sensitive to the shear treatment than the flexible amorphous structure in amylose. This mechanistic understanding at the microstructure level is helpful in designing the processing of starch-based foods or plastics with desired functional properties.

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“…The role of phosphorylase in forming enzyme complexes between different enzymes and isoforms of these (Tetlow et al, 2008;Tetlow, Morell & Emes, 2004;Tetlow et al, 2004) contributes to the action of each enzyme set. One important use of this model is that the parameters obtained by fitting (the β and h values) accurately express the whole CLD (including quite subtle features (Wu, Witt & Gilbert, 2013)) in a small number of physically meaningful parameters. This is a major improvement over representing a CLD by empirical parameterizations such as fractions in arbitrarily chosen ranges of DP.…”

Section: Fitting Amylopectin Number Clds With a Biosynthesis Modelmentioning

confidence: 99%

Instrumental measurement of cooked rice texture by dynamic rheological testing and its relation to the fine structure of rice starch

Prakash

Nicholson

et al. 2016

Carbohydrate Polymers

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122

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Instrumental measurement of cooked rice texture by dynamic rheological testing and its relation to the fine structure of rice starch.Carbohydrate Polymers http://dx.doi.org/10. 1016/j.carbpol.2016.03.045 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. and dynamic rheological testing) using a set of 18 varieties of rice with a wide range in amylose content (0 -30%). The panellists' results indicated that hardness and stickiness were the two most discriminating attributes among 13 tested textural attributes. The consistency coefficient (K * ) and loss tangent (tan δ) from a dynamic frequency sweep were used to compare with hardness and stickiness tested by TPA and sensory panellists, showing that using K * to express hardness, and tan δ to express stickiness, are both statistically and mechanistically meaningful. The instrumental method is rationalized in terms of starch structural differences between rices: a higher proportion of both amylose and long amylopectin branches with DP 70-100 causes a more elastic and less viscous texture, which is readily understood in terms of polymer dynamics in solution.

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Characterization Methods for Starch-Based Materials: State of the Art and Perspectives

Cited by 60 publications

References 131 publications

Competition between Granule Bound Starch Synthase and Starch Branching Enzyme in Starch Biosynthesis

Competition between Granule Bound Starch Synthase and Starch Branching Enzyme in Starch Biosynthesis

Shear degradation of corn starches with different amylose contents

Instrumental measurement of cooked rice texture by dynamic rheological testing and its relation to the fine structure of rice starch

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