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Article

Glass Transition in Rice Pasta as Observed by Combined Neutron Scattering and Time-Domain NMR

1
Department of Biotechnology and General Technology of Food, Faculty of Food Technology, University of Agriculture in Krakow, Balicka 122, 30-149 Krakow, Poland
2
ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX, UK
3
Department of Engineering and Machinery for Food Industry, Faculty of Food Technology, University of Agriculture in Krakow, Balicka 122, 30-149 Krakow, Poland
*
Author to whom correspondence should be addressed.
Academic Editor: Nicolas Sbirrazzuoli
Polymers 2021, 13(15), 2426; https://doi.org/10.3390/polym13152426
Received: 21 June 2021 / Revised: 16 July 2021 / Accepted: 20 July 2021 / Published: 23 July 2021
(This article belongs to the Section Biomacromolecules, Biobased and Biodegradable Polymers)
Experimental protocols aiming at the characterisation of glass transition often suffer from ambiguity. The ambition of the present study is to describe the glass transition in a complex, micro heterogeneous system, the dry rice pasta, in a most unambiguous manner, minimising the influence of technique-specific bias. To this end, we apply an unprecedented combination of experimental techniques. Apart from the usually used NMR and DSC, we employ, in a concurrent manner, neutron transmission, diffraction, and Compton scattering. This enables us to investigate the glass transition over a range of spatio-temporal scales that stretches over seven orders of magnitude. The results obtained by neutron diffraction and DSC reveal that dry rice pasta is almost entirely amorphous. Moreover, the glass transition is evidenced by neutron transmission and diffraction data and manifested as a significant decrease of the average sample number density in the temperature range between 40 and 60 °C. At the microscopic level, our NMR, neutron transmission and Compton scattering results provide evidence of changes in the secondary structure of the starch within the dry rice pasta accompanying the glass transition, whereby the long-range order provided by the polymer structure within the starch present in the dry rice pasta is partially lost. View Full-Text
Keywords: glass transition; NMR relaxation; DSC; neutron diffraction; neutron transmission; neutron Compton scattering; average functional group approximation glass transition; NMR relaxation; DSC; neutron diffraction; neutron transmission; neutron Compton scattering; average functional group approximation
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MDPI and ACS Style

Witek, M.; Krzystyniak, M.; Romanelli, G.; Witczak, T. Glass Transition in Rice Pasta as Observed by Combined Neutron Scattering and Time-Domain NMR. Polymers 2021, 13, 2426. https://doi.org/10.3390/polym13152426

AMA Style

Witek M, Krzystyniak M, Romanelli G, Witczak T. Glass Transition in Rice Pasta as Observed by Combined Neutron Scattering and Time-Domain NMR. Polymers. 2021; 13(15):2426. https://doi.org/10.3390/polym13152426

Chicago/Turabian Style

Witek, Magdalena, Maciej Krzystyniak, Giovanni Romanelli, and Teresa Witczak. 2021. "Glass Transition in Rice Pasta as Observed by Combined Neutron Scattering and Time-Domain NMR" Polymers 13, no. 15: 2426. https://doi.org/10.3390/polym13152426

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