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19 results on '"MacNaughtan, Bill"'

8. Extending the functionality of arrowroot starch by thermally assisted high hydrostatic pressure

Author

Oliveira, Ludmilla C., Macnaughtan, Bill, Gouseti, Ourania, Villas-Boas, Flávia, Clerici, Maria T. P. S., Bakalis, Serafim, Muttakin, Syahrizal, Cristianini, Marcelo, Oliveira, Ludmilla C., Macnaughtan, Bill, Gouseti, Ourania, Villas-Boas, Flávia, Clerici, Maria T. P. S., Bakalis, Serafim, Muttakin, Syahrizal, and Cristianini, Marcelo

Abstract

The modification of native arrowroot starch (NAS) properties by thermally assisted high hydrostatic pressure (HHP) was investigated. Changes in the structure of the granules were produced by HHP. This was enhanced when HHP was applied together with a temperature increase to 50℃, for 15 or 25 min. Processing at 400 MPa/25℃ had minimal effect. As pressure and/or temperature increased, processed arrowroot starches progressively lost the Maltese cross and granular structure. There was also a decrease in the enthalpy of the gelatinization which occurred between 61.3 and 80.3℃. The relative crystallinity of NAS was reduced, depending on the severity of treatment, by 6.81%–35.74%. A principal components analysis showed a clear trajectory depending on processing conditions. The most severe treatment 650 MPa/50℃ did not produce complete gelatinization. Thermally assisted HHP demonstrated advantages over at 25℃ and produced a physically modified version of the arrowroot starch, with potential as a clean label ingredient. Novelty impact statement: This study with arrowroot starch (AS) has revealed a pronounced effect of high hydrostatic pressure (HHP) when applied together with mild temperature (50℃), compared with conventional processes at room temperature, and consequent lowering of onset pressure for structural changes of starch. Modified AS with a several different functionalities may be produced by thermally assisted HHP, whose techno-functional properties correspond well with the measurements of structural order. The results of this work support the industrial potential of this unconventional starch as a clean label ingredient.

Published
2021

10. Efeito do sorbitol em relaxação estrutural de fi lmes de gelatina em estado vítreo

Author

Díaz-Calderón, Paulo, Quero, Franck, MacNaughtan, Bill, Rousennova, Mina, and Enrione, Javier

Subjects
gelatin, plasticizers, estado vítreo, Gelatina, plastifi cantes, plastificantes, physical aging, relajación entálpica, glassy state, relaxação estrutural
Abstract

El objetivo de este trabajo fue evaluar el efecto del sorbitol sobre la cinética de relajación estructural de películas de gelatina almacenadas bajo la temperatura de transición vítrea (Tg). Películas de gelatina de bovino y sorbitol fueron preparadas mediante casting en frío. El sorbitol fue agregado en fracciones en peso (Qs) de 0,0, 0,06 y 0,10. Las películas fueron acondicionadas en un ambiente de humedad relativa constante (44%) utilizando una solución saturada de carbonato de potasio, obteniéndose fracciones de contenido de humedad en peso (Qw) de 0,18, 0,16 y 0,18 respectivamente. La entalpía de relajación (ΔH) fue determinada mediante Calorimetría Diferencial de Barrido (DSC). Las muestras utilizadas en este estudio presentaron valores de Tg de 48°C (Qs=0,0), 35°C (Qs=0,06) y 30°C (Qs=0,10). Luego de eliminar el historial térmico (30°C sobre Tg, 15min), las muestras fueron almacenadas isotérmicamente a 10°C bajo Tg onset entre 2 y 80 horas. La adición de sorbitol produjo una reducción signifi cativa (p

Published
2015

18. What Does LiOH Treatment Offer for Lyocell Fibers? Investigation of Structural Changes.

Author

Öztürk, Hale Bahar, MacNaughtan, Bill, Mitchell, John R., and Bechtold, Thomas

Subjects
*LITHIUM compounds, *FIBERS, *CELLULOSE, *HYDRATES, *SOLUTION (Chemistry), *X-ray diffraction
Abstract

Lyocell fibers, regenerated cellulosic fibers spun from cellulose/N-methylmorpholine-N-oxide hydrate solution by wet spinning, were treated with LiOH aqueous solution at concentrations of up to 7.5 M to study the inter- and intrafibrillar changes. Wide-angle X-ray diffraction analyses were applied to identify the crystallinity index and crystallite size. Inverse size-exclusion chromatography was applied to study the pore structure of the swollen fibers. The mean pore diameter was found to increase after the LiOH treatment. The carboxyl content, measured by methylene blue sorption, decreased slightly. The water retention value, depth of color measured after dyeing with CI Direct Red 81, and weight loss of fibers changed gradually after LiOH treatment at concentrations up to ca. 5 M. The treated fibers became brittle as a result of both inter- and intrafibrillar swelling and the deep penetration ability of LiOH treatments above 5 M. [ABSTRACT FROM AUTHOR]

Published
2011
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19. Changes in the intra- and inter-fibrillar structure of lyocell (TENCEL®) fibers caused by NaOH treatment.

Author

Öztürk, Hale, Potthast, Antje, Rosenau, Thomas, Abu-Rous, Mohammad, MacNaughtan, Bill, Schuster, K., Mitchell, John, and Bechtold, Thomas

Subjects
FIBERS, SODIUM hydroxide, CELLULOSE, DYES & dyeing, FLUORESCENCE, MOLECULAR weights, POROUS materials, TRANSMISSION electron microscopy
Abstract

Some effects of NaOH treatment at concentrations of up to 8 M on (1) the porous structure, (2) the degree of swelling, (3) carboxyl content using methylene blue sorption and 9H-fluoren-2-yl-diazomethane (FDAM) methods, (4) dyeing, (5) the molecular weight distribution measured by gel permeation chromatography (GPC), (6) crystallinity determined by wide angle X-ray diffraction (WAXD) and (7) the tensile properties of lyocell fibers were investigated. The porous structure of fibers was visualised using fluorescence microscopy and transmission electron microscopy (TEM) on fiber cross-sections and was also studied by inversion size exclusion chromatography (ISEC). Mean pore diameter and pore area of fibers were not changed by NaOH treatments. The pore volume increased above 2.5 M NaOH. NaOH-treated samples showed higher dye uptake, higher swelling, but lower carboxyl and moisture content and increased crystallinity. As the NaOH concentration increased, the depth of colour following dyeing with C.I. Direct Red 81 also increased due to deep penetration of alkali into the fiber. In general, fiber properties were distinctly different in the ranges 0 to approximately 3 and 3–8 M NaOH. [ABSTRACT FROM AUTHOR]

Published
2009
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