Papers by Mohamed Mathlouthi
Carbohydrate Polymers, 2015
Although green macro-algae represent a renewable and highly abundant biomass, they remain poorly ... more Although green macro-algae represent a renewable and highly abundant biomass, they remain poorly exploited in terms of carbohydrate polymers compared to red and brown ones and other lignocellulosic materials. In this study, cellulose from the green macro-algae Enteromorpha sp. was isolated, physico-chemically characterized and enzymatically functionalized. The cellulose content was about 21.4% (w/w). FTIR analyses indicated an absence of acetyl or uronic esters confirming the absence of hemicellulose contamination. The 36% crystallinity index of the extracted cellulose revealed a high amorphous character as determined by X-ray diffraction. The moisture adsorption isotherms and specific surface measurements were respectively 42.87g/100g and 8.34m(2)/g. The Enteromorpha sp. cellulose was first enzymatically saccharified by a commercial cellulase preparation from Aspergillus niger with a hydrolysis yield of 70.4%. Besides, it was successfully functionalized based on the transglycosylation mechanism of the same enzymatic preparation, to produce highly added-value biosurfactants (butyl-glucoside) with a concentration of 8mM.
Carbohydrate Research, Mar 1, 1986
The structure of noncrystalline sucrose in the amorphous, solid state and in aqueous solution was... more The structure of noncrystalline sucrose in the amorphous, solid state and in aqueous solution was investigated. Differences of structure of amorphous solid samples, the quenched-melt, and freeze-dried sucrose, are revealed by differential thermal analysis (d.t.a.) and from the Fourier-transform infrared (F-t.-i.r.) spectra. Factor analysis of the F.t.4.r. spectra of aqueous solutions of sucrose shows the existence of at least two forms of the sucrose molecule. Analysis of 13C-n.m.r. spectra of amorphous and crystalline sucrose reveals a sensitivity of the fructosyl moiety to the morphology of the sample.
Food Chemistry, Jul 1, 2003
Water vapour sorption isotherms describe the relationship between water content and water activit... more Water vapour sorption isotherms describe the relationship between water content and water activity. Depending on the nature of food powder (crystalline or amorphous), the shape of isotherm is different. Mostly food powders have complex structures, including potentially crystallisable solutes such as sugars, which show changes in crystallinity during the adsorption of water. Even for such an apparently simple system as crystalline sugar, numerous factors affect the adsorption of water vapour and, as a consequence, the storage stability. The presence of a thin film of saturated solution at the surface of the crystal, grain size distribution and the inclusion of mother liquor droplets in the crystal are some of the factors which perturb the equilibrium relative humidity of sugar and its aptitude to caking. These conditions were carefully studied at the level of the laboratory and in a pilot silo. Conditions of ''decaking'' (recovering a flowing sugar after caking) were also established. In the case of noncrystalline powders, water activity, together with glass transition temperature, is important to determine if it is necessary to interpret the origin of the formation of bridges between food powder particles and the caking phenomenon. #
Carbohydrate Polymers, Nov 30, 1998
The rate of sucrose crystallization in supersaturated solutions is known to include at least two ... more The rate of sucrose crystallization in supersaturated solutions is known to include at least two steps: the diffusion of sucrose from the bulk solution to the thin layer at the interface crystal/solution and the incorporation of sucrose molecules in the crystal after the release of their hydration water. Among the energy barriers encountered in the 'hurdle race' of the crystallization process, viscosity seems to be a minor hurdle and the disassociation of hydration water a major one. We will attempt to show that the dehydration of sucrose molecules prior to their incorporation into the crystal plays an important part in the crystallization process and propose to conceive the mechanism of crystal growth as mainly based on the release of water molecules and their diffusion in the bulk solution rather than a migration of sucrose from the solution to the crystal. ᭧
Journal of Advances in Chemistry, Aug 28, 2014
crystals of a new hybrid compound, (C5H6N2O)2[Co(H2O)6]3(SO4)4.2H2O, were synthesized in aqueous ... more crystals of a new hybrid compound, (C5H6N2O)2[Co(H2O)6]3(SO4)4.2H2O, were synthesized in aqueous solution and characterized. This compound crystallizes in the triclinic system with the space group P-1, the unit cell :a=6.632(3) Å, b=11.769(5) Å, c=14.210(6) Å, α=67.86(4)°, β=81.32(4)°, γ=85.18(4)° and V=1015.14(8) Å 3 . Its crystal structure can be described as a packing of alternated inorganic and organic layers. The different components are connected by a threedimensional network of O-H…O and N-H…O hydrogen bonds.
Industries Alimentaires Et Agricoles, 2005
... de sucre Barbara Rogé, Mohamed Mathlouthi, Laboratoire de Chimie Physique Industrielle, UMR F... more ... de sucre Barbara Rogé, Mohamed Mathlouthi, Laboratoire de Chimie Physique Industrielle, UMR FARE, UFR Sciences, Université de Reims Champagne-Ardenne ... Ceci implique la connaissance du nombre de cristaux à obtenir par unité de volume de masse-cuite. ...
J Chem Crystallography, 1990
C12H20O10,M r=324.28, orthorhombic,P212121,a=9.4476(8),b=10.2247(8),c=13.5827(11) Å,V=1312.07(18)... more C12H20O10,M r=324.28, orthorhombic,P212121,a=9.4476(8),b=10.2247(8),c=13.5827(11) Å,V=1312.07(18) Å3,Z=4,D x=1.642 g cm–3, MoK radiation (=0.71073 Å)=1.4 cm–1,F(000)=688,T=295 K, finalR=0.041 for 1089 reflections withI2.5a(I). The molecule consists of a-d-fructopyranose and a -d-fructofuranose ring which are linked by a 1,4-dioxane ring. The pyranose ring and the dioxane ring both have a chair conformation, and the furanose ring has an envelope conformation. All six hydroxyl groups act
Before dealing with the important technical progress in sugar processing during the finishing cen... more Before dealing with the important technical progress in sugar processing during the finishing century, it is of relevance to glance at the preceding centuries to know where this industry comes from. Innovations in sugar cane technology were imposed by economic constraints already in the 18 th and 19 th century. Labour and energy costs are two of the expenses to reduce if it is desired to increase profitability. As long as slavery was not abolished, there was no need of innovation. A technological advance and important economy of fuel was achieved by the substitution of firewood by bagasse and the introduction of the three-roller mill which leaves the cane stalks intact and combustible after drying. The second achievement was the Jamaican train, which consists in a battery of 5 or 6 cauldrons heated by one fire through internal flues which improves the efficiency in fuel consumption. The battery is designed so that greater heat could be applied to smaller cauldrons than to the larger ones. The juice was clarified in the two first cauldrons and boiled to the point of crystallisation in the remaining cauldrons. Adding of rye, lime or ash was made by slaves who had to agitate, mix, skim or discharge a cauldron in another at temperatures above 100°C in conditions so bad as to be compared by a Jesuit Portuguese priest to a vision of souls in Hell.
Carbohydrate Polymers
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International Sugar Journal
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Acta Crystallographica Section C-crystal Structure Communications, 1989
Advances in Carbohydrate Chemistry and Biochemistry, 1987
Trends in Food Science & Technology, 1996
... Spain Page 11. CONTR1BUTORS lX F. Riquelme F. Romojaro JP Roozen B. Roser M. Serrano AM Seuvr... more ... Spain Page 11. CONTR1BUTORS lX F. Riquelme F. Romojaro JP Roozen B. Roser M. Serrano AM Seuvre R. Sieber J. Smegen JJ Wright Consejo Superior de lnvestigaciones Cientificas Centro de Edafologia Y Biologica Aplicada del Segura. Av. ... G. MART1NEZ. M. SERRANO. ...
Trends in Food Science & Technology, 1990
Journal of the Science of Food and Agriculture, 1990
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Journal of the Science of Food and Agriculture, 1991
Instron measurement and sensory analysis of sponge cake texture was performed under various condi... more Instron measurement and sensory analysis of sponge cake texture was performed under various conditions. The samples were compared on the basis of their storage in modified atmosphere (CO, IN,, 50:50 v ) or not, at +4"C or +20"C, as whole cakes or slices of cake, and with or without additives (soya bean protein or sodium alginate). It was found that the best conditions for preservation of a soft texture in a whole cake are obtained in a modified atmosphere at +4"C when 10 g kg-l soya bean protein is included in the sponge cake formulation.
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Papers by Mohamed Mathlouthi