Solid state NMR studies on the structural and conformational properties of natural maize starches

Cheetham, Norman W.H.; Tao, Leping

doi:10.1016/s0144-8617(98)00004-6

Cited by 104 publications

(69 citation statements)

References 25 publications

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“…According to the current models of starch granule, parallel double amylopectin molecules result in the formation of crystalline regions, while amylose molecules result in the formation of amorphous regions in the starch structure (Cheetham and Tao, 1998). The X-ray diffractograms of the three starch samples are presented in Fig.…”

Section: X-ray Diffractometrymentioning

confidence: 99%

Physicochemical properties of starches from two different yam (Dioscorea opposita Thunb.) residues

Wang

Zhang

et al. 2011

Braz. arch. biol. technol.

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The starches obtained from two different yam residues, which were treated with alkali(starch-A) or enzyme (starch-E), were studied and compared with yam starch isolated using ordinary method (starch-O) for morphological, crystalline pattern, thermal, and pasting properties. The results revealed that the amylose content of three starches ranged from 19.47 to 22.17%. The granule surfaces of starch-A and starch-E were as smooth as that of starch-O. The crystalline pattern of the three starches was a C-type. The transition temperatures (T o , T p and T c ) varied from 70.11 to 73.64, 79.23 to 81.74, and 84.30

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Section: X-ray Diffractometrymentioning

confidence: 99%

Physicochemical properties of starches from two different yam (Dioscorea opposita Thunb.) residues

Wang

Zhang

et al. 2011

Braz. arch. biol. technol.

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“…Previous papers (Gidley and Bociek 1985;Gidley and Bociek 1988;Cheetham and Tao 1998) have reported the amylose content has a different effect on 13 C NMR spectra of starches in the solution and solid state. In the solid state, 13 C CP/MAS spectras of maize starches with different amylose contents are similar, indicating that their overall conformation is almost independent of the amylose/amylopectin ratio, although amylose and amylopectin differ in average chain length, linkage mode, physical and chemical properties (Cheetham and Tao 1998).…”

Section: Nmrmentioning

confidence: 96%

“…Combination of both techniques has provided much important information about secondary structures and molecular order of a number of molecular systems (Cheetham and Tao 1998). The study of the equilibria between configurational and conformational isomers of carbohydrates in solution is a classical application of NMR spectroscopy (Jeffrey, Wood et al 1983).…”

Section: Nmrmentioning

confidence: 99%

“…This downfield shift and the shoulder at ~95 ppm are believed to arise from noncrystalline material. As for the chemical shift differences between solid and liquid spectra is due to 13 C chemical shifts in the solid state are determined by a range of fixed values of the dihedral angles, while those in aqueous solution are time averaged as a result of rapid conformational isomerisation (Saitô, Izumi et al 1982;Cheetham and Tao 1998).…”

Section: Nmrmentioning

confidence: 99%

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Starch Gelatinization under Shearless and Shear Conditions

Xie¹,

Liu²,

Chen³

et al. 2007

International Journal of Food Engineering

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This article reviews the development of studying starch gelatinization under shear and shearless conditions, in particular the technologies used to detect the degree of gelatinization. Advantages and disadvantages of each technology were discussed and then some examples were presented to demonstrate their application. A new technology RheoScope, an instrument that can measure viscosity under shear stress and simultaneously observes variation of starch particles using a microscope, was also introduced. It was found the definition of "gelatinization" could be different for different detection technologies. Under shearless condition full gelatinization of starch needs about ratio of water 3/starch 1, while the gelatinization under shear condition requires less water content since shear stress enhances the processing. The number of endotherm and enthalpy of gelatinization depends on amylose/amylopectin, moisture and lipid content.

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“…Difraktogram pembelauan sinar-X sampel kanji, hidrogel akrilamida dan hidrogel berkanji yang dihasil Berdasarkan Rajah 7, kanji Ubi Stemona curtisi menunjukkan sifat penghabluran dengan beberapa puncak keamatan yang tinggi pada belauan dengan skala 2θ 15˚, 17˚, 18˚ dan 23˚. Hal ini berlaku kerana disebabkan oleh kehadiran molekul berganda amilopektin di dalam struktur kanji yang boleh menghasilkan satu kawasan kristal jika molekul-molekul tersebut berada pada susunan selari antara satu sama lain manakala molekul amilosa hanya akan membentuk kelompok dan mewujudkan satu rantau tak berhablur yang membawa kepada sifat keamorfusan kanji [19,20].…”

Section: Analisis Spektrometer Inframerah Transformasi Fourier-jumlahunclassified

PENYEDIAAN DAN PENCIRIAN HIDROGEL BERASASKAN KANJI/AKRILAMIDA DARIPADA UBI Stemona curtisii

Pin¹,

Ashri²,

Bakar³

et al. 2016

MJAS

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AbstrakDalam kajian ini, hidrogel berasaskan kanji daripada ubi Stemona curtisii disintesis melalui kaedah pempolimeran radikal bebas menggunakan penyinaran gelombang mikro. Dalam kajian ini terdapat 3 jenis hidrogel dengan nisbah kanji kepada akrilamida yang berbeza dianalisis iaitu 1:3, 1:4 dan 5:3. Berdasarkan kepada ujian pembengkakan, hidrogel 1:3 mempunyai peratus pembengkakan paling tinggi dan ini dibuktikan dengan keputusan yang diperolehi daripada Mikroskop Pengimbas Elektron (SEM) di mana mikrograf SEM mempamerkan saiz liang pada hidrogel 1:3 adalah yang paling besar. Analisis menggunakan Spektroskopi Inframerah Transformasi Fourier-Jumlah Pantulan Teratenuat (ATR-FTIR) menunjukkan kehadiran puncak pada 1112 cm -1 , 1152 cm -1 dan 1150 cm -1 pada hidrogel 1:4, 1:3 dan 5:3 masing-masing yang menandakan pembentukan ikatan C-O-C hasil daripada proses pempolimeran taut silang. Analisis menggunakan Difraktometer Sinar-X (XRD) pula menunjukkan bahawa ketiga -tiga jenis hidrogel adalah amorfus. Kalorimeter Pengimbas Kebedaan (DSC) pula memberikan maklumat bahawa semua bahan yang digunakan untuk sintesis hidrogel adalah pada tahap kebolehcampuran yang baik dan hidrogel 1:4 menunjukkan suhu peralihan kaca (T g ) yang paling tinggi. Daripada termogram TGA/DTG pula, hidrogel 5:3 didapati lebih stabil terhadap haba berbanding hidrogel yang lain. Keputusan ujian Tegangan menggunakan Mesin Ujian Universal (UTM) telah mendapati bahawa hidrogel berasaskan kanji Ubi Stemona curtisii yang disintesis mempunyai potensi untuk diaplikasikan sebagai pembalut luka. Dalam ujian ini, hidrogel 1:4 yang mempunyai kandungan kanji yang paling rendah telah menunjukkan nilai modulus elastik Young yang paling tinggi. Kata kunci: Stemona curtisii, hidrogel, pempolimeran radikal bebas, gelombang mikro AbstractIn this study, hydrogel based on starch of Stemona curtisii was synthesized via free radical polymerization method by using microwave irradiation. In this study, there were three type of hydrogels formulated with different type of starch to acryamide been anaylyzed which were 1:3, 1:4 and 5:3. Based on swelling test, hydrogel with 1:3 was reported to have the highest swelling percentage where this is prove by Scanning Electron Microscope result. The SEM micrograph shows that hydrogel 1:3 have the largest pores size compare to the other two types of hydrogels. The polymerization reaction has been proven to occur successfully based on the analysis using Attenuated Total Reflection-Fourier Transform Infrared Spectroscopy (ATR-FTIR). Cross-linking polymerization process was determine by the present of peak at 1112 cm -1 , 1152 cm -1 and 1150 cm -1 in hydrogels 1:4, 1:3 and 5:3 respectively which indicate the formation of C-O-C bond.X-Ray Diffractometer (XRD) results showed that all starch-based hydrogels were amorphous. Differential Scanning Calorimeter (DSC) gave information that all the blending materials for hydrogel synthesis were of good miscibility and the hydrogel 1:4 was found to have the highest glass transition temperature. F...

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Solid state NMR studies on the structural and conformational properties of natural maize starches

Cited by 104 publications

References 25 publications

Physicochemical properties of starches from two different yam (Dioscorea opposita Thunb.) residues

Physicochemical properties of starches from two different yam (Dioscorea opposita Thunb.) residues

Starch Gelatinization under Shearless and Shear Conditions

PENYEDIAAN DAN PENCIRIAN HIDROGEL BERASASKAN KANJI/AKRILAMIDA DARIPADA UBI Stemona curtisii

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