Double-helical network in amylose as seen by slow calorimetry and FTIR

Bernazzani, Paul; Chapados, Camille; Delmas, G.

doi:10.1002/(sici)1099-0488(20000615)38:12<1662::aid-polb120>3.0.co;2-6

Cited by 28 publications

(26 citation statements)

References 24 publications

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“…When using FTIR, the 1,065 870 cm 1 spectral region is assigned to C-O-C, C-C, and C-H stretching modes, and some peaks have been attributed to ordered (995, 1,047 cm 1 ) or amorphous (1,022 cm 1 ) starch (Bernazzani et al 2000;Capron et al 2007;Wilson et al 1987;van Soest et al 1995). According to Fang and coworkers (2002), the bands located at 1,023 and 1,083 cm 1 could be assigned to the C-O bond stretching in the C-O-C group of the anhydroglucose rings.…”

Section: About Crystallinitymentioning

confidence: 99%

Starch

2015

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Section: About Crystallinitymentioning

confidence: 99%

Starch

2015

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“…As WAXD revealed systematic higher crystallinities at T c for regular than for waxy starches, a plausible role of amylose in the formation of hydrogen-bonded networks is indeed envisaged. [46][47][48] Differences in rate of network formation and network-forming capacity can be anticipated for amylose and different amylopectins, and the resulting diverse exothermic events at the hightemperature side of the gelatinization endotherm may lead to inaccuracies in the determination of T c .…”

Section: Starch Gelatinizationmentioning

confidence: 99%

Gelatinization of Starch in Excess Water: Beyond the Melting of Lamellar Crystallites. A Combined Wide- and Small-Angle X-ray Scattering Study

et al. 2006

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The gelatinization of waxy rice, regular rice, and potato starch suspensions (66% w/w moisture) was investigated by real-time small-angle X-ray scattering (SAXS) and wide-angle X-ray diffraction (WAXD) during heating and by fast ramp differential scanning calorimetry (DSC). The high-angle tail of the SAXS patterns suggested the transition from surface to mass fractal structures in the DSC gelatinization range. Amylose plays a major role in determining the dimensions of the self-similar structures that develop during this process as the characteristic power-law scattering behavior extends to lower scattering angles for regular than for waxy starches. Crystallinity of A-type starches is lost in the temperature region roughly corresponding to the DSC gelatinization range. At the end of the gelatinization endotherm, the B-type potato starch showed residual crystallinity (WAXD), while SAXS-patterns exhibited features of remaining lamellar stacks. Results indicate that the melting of amylopectin crystallites during gelatinization is accompanied by the (exothermic) formation of amorphous networks.

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“…One does not expect that increase in long‐range order associated with the treatment will alter the ir spectra significantly since the effect of the environment on a vibration is not long‐ranged †. X‐ray measurements have been performed on the f ( T max , C rys ) samples 25. They show an increase of the diffraction peaks corresponding to the B and V crystals when T max is raised.…”

Section: Discussionmentioning

confidence: 99%

“…Order in the amorphous phase of starch has been proposed to interpret the chemical shift range observed in the material 14. Analyses of slow dissolution traces of samples with long‐range order prepared as described in the present work has been made recently 25. The enthalpy evolved on the same temperature interval range from 60 to 140 J/g.…”

Section: Introductionmentioning

confidence: 96%

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Phase change in amylose-water mixtures as seen by Fourier transform infrared

2001

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The phase content of amylose–water mixtures (0.7/0.3 w/w) has been analyzed by transmission Fourier transform infrared (FTIR) spectroscopy in the 1175–950 cm−1 region. Spectra are obtained under three different conditions: (a) as a function of temperature (T) from 25 to 97°C; (b) at room temperature (RT), after slow cycles of T; and (c) at RT after quenching. Tmax, the maximum temperature in the cycle, ranges from 50 to 120°C. The quality of the seven‐band spectra allows for an unambiguous determination of each band area. Unexpectedly, slow cooling after different Tmax brings about wide changes in the spectra while quenching does not. Two jumps in the absorbance are found: one at 70°C and the other above 105°C. Previous work on slow calorimetry of amylose–water mixtures suggests that these temperatures correspond to the beginning and the end of the same physical phenomena that takes place slowly between these two temperatures—namely the dissolution of the strained network phase. The spectra have two distinct regions, the low wavenumber region (1078–950 cm−1) and the high wavenumber region (1175–1078 cm−1). A distinct gain in the integrated absorbance of the 1175–1078 cm−1 region at the expanse of that of the 1078–950 cm−1 region when Tmax increases is interpreted as a change from strained to unstrained environments. A nonequilibrium state between the chains is a strained environment. In light of the 13C NMR evaluation of the change of molecular order with T, the observed changes of the ir spectra could correspond to a transformation of a network of double helices into freer chains, possibly single helices. The present in‐depth analysis of equilibrium or near equilibrium states by FTIR can serve to understand, through in situ spectra, molecular mechanisms during the gelation/crystallization of amylose and other gel‐forming polymers. © 2001 John Wiley & Sons, Inc. Biopolymers 58: 305–318, 2001

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Double-helical network in amylose as seen by slow calorimetry and FTIR

Cited by 28 publications

References 24 publications

Starch

Starch

Gelatinization of Starch in Excess Water: Beyond the Melting of Lamellar Crystallites. A Combined Wide- and Small-Angle X-ray Scattering Study

Phase change in amylose-water mixtures as seen by Fourier transform infrared

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