Light Scattering Techniques

Burchard, Walther

doi:10.1007/978-1-4615-2101-3_4

Cited by 53 publications

(45 citation statements)

References 79 publications

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“…The radius of gyration, R g is related to M w according to the equation R g kM a . a has values of 0.33, 0.60 and 1.0 for spheres, random coils and rigid rods, respectively (Burchard, 1994) and can be obtained from the slope of the plot of log R g versus log M w . The plots of log R g agaisnt log M w for amylose and amylopectin respectively are shown in Figs.…”

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confidence: 99%

Physico-chemical characterisation of sago starch

Ahmad

Williams

Doublier³

et al. 1999

Carbohydrate Polymers

211

119

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The physico-chemical characteristics of various sago starch samples from South East Asia were determined and compared to starches from other sources. X-ray diffraction studies showed that all the sago starches exhibited a C-type diffraction pattern. Scanning electron microscopy showed that they consist of oval granules with an average diameter around 30 mm. Proximate composition studies showed that the moisture content in the sago samples varied between 10.6% and 20.0%, ash between 0.06% and 0.43%, crude fat between 0.10% and 0.13%, fiber between 0.26% and 0.32% and crude protein between 0.19% and 0.25%. The amylose content varied between 24% and 31%. The percentage of amylose obtained by colourimetric determination agreed well with the values obtained by fractionation procedures and potentiometric titration. Intrinsic viscosities and weight average molecular weight were determined in 1M KOH. Intrinsic viscosity for amylose from sago starches varied between 310 and 460 ml/g while for amylopectin the values varied between 210 and 250 ml/g. The molecular weight for amylose was found to be in the range of 1.41 × 10 6 to 2.23 × 10 6 while for amylopectin it was in the range of 6.70 × 10 6 to 9.23 × 10 6 . The gelatinisation temperature for the sago starches studied varied between 69.4ЊC and 70.1ЊC. The exponent 'a' in the Mark-Houwink equation and the exponent 'a ' in the equation R g kM a was found to be 0.80 and 0.58, respectively for amylose separated from sago starch and these are indicative of a random coil conformation. Two types of pasting properties were observed. The first was characterised by a maximum consistency immediately followed by sharp decrease in consistency while the second type was characterised by a plateau when the maximum consistency was reached. ᭧

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mentioning

confidence: 99%

Physico-chemical characterisation of sago starch

Ahmad

Williams

Doublier³

et al. 1999

Carbohydrate Polymers

211

119

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“…The structure-sensitive parameter is defined as the ratio of the radius of gyration R g obtained from static light scattering to the hydrodynamic radius R h from dynamic light scattering (Burchard, Schmidt, & Stockmayert, 1980;Burchard, 1994Burchard, , 2003Burchard, , 2008. Generally, the value of decreases with increasing branching density, but an increase in polydispersity counteracts the effect of branching.…”

Section: Dynamic Light Scatteringmentioning

confidence: 99%

“…Static and hydrodynamic dimensions vary characteristically with the structure of the macromolecules, and a combination of the two may provide qualitative information on the architecture of the macromolecules (Burchard, 1994(Burchard, , 2003Wang et al, 2005). The structure-sensitive parameter is defined as the ratio of the radius of gyration R g obtained from static light scattering to the hydrodynamic radius R h from dynamic light scattering (Burchard, Schmidt, & Stockmayert, 1980;Burchard, 1994Burchard, , 2003Burchard, , 2008.…”

Section: Dynamic Light Scatteringmentioning

confidence: 99%

“…Static light scattering data presented in a Zimm plot obtained from C. ferrea galactomannan (1 mg/ml) in 0.1 M sodium nitrite solution containing 0.02% (w/w) sodium azide. the macromolecule (Burchard, 1994(Burchard, , 2008 and was determined to be 94.9 nm. This value is similar to that obtained for other galactomannans such as guar gum (Picout, Ross-Murphy, Errington, & Harding, 2001) and locust bean and carob gum (Picout et al, 2002).…”

Section: Static Light Scatteringmentioning

confidence: 99%

“…Light scattering measurements are the most important techniques for determining dilute polymer solutions . Static and dynamic light scattering are two different techniques for measuring the patterns of light scattered from a polymer in solution (Burchard, 1994(Burchard, , 2008Kato, Katsuki, & Takahashi, 1984;Li, Wang, Cui, Huang & Kakuda, 2006;Pinder, Nash, Hemar, & Singh, 2003;Wang, Huang, Nakamura, Burchard, & Hallett, 2005;Zulfiqar, Lieberwirth, & Sarwar, 2008). Static light scattering (SLS) measures light intensity as a function of scattering angle and solute concentration.…”

Section: Introductionmentioning

confidence: 99%

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Caesalpinia ferrea var. ferrea seeds as a new source of partially substituted galactomannan

Souza

Lucyszyn

Ferraz

et al. 2010

Carbohydrate Polymers

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a b s t r a c tThe hydrocolloid extracted from Caesalpinia ferrea var. ferrea seeds purified by membrane filtration was denominated GMPF (14% yield) and contained 75% total carbohydrate and 9% protein, and the mannose to galactose (Man:Gal) ratio was around to 2.1:1.0. The periodate oxidation, methylation and 1D/2D NMR spectra results indicated galactomannan (GM) with a (1 → 4)-linked ␤-d-mannopyranose backbone, partially substituted at O-6 with single-unit ␣-d-galactopyranose side-chains. The splitting of three 13 C signals in the regions of the 4-O-Manp units revealed that the ␣-d-Galp units were irregularly (54%) distributed at the main chain. By rheology, GPC-coupled to multi-detectors, static and dynamic light scattering it was observed that the GM in nitrite solution presented an intrinsic viscosity of 860 mL/g, a polydispersity of 1.55, and a structural parameter (R g /R h ) of 1.77, showing a random coil and flexible conformation, which was confirmed by the Mark-Houwink constant˛(0.63). The results suggest that GMPF can be a new source of GM.

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