References of "Garna, H"
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See detailChemical composition and functional properties of Ulva lactuca seaweed collected in Tunisia
Yaich, H.; Garna, H.; Besbes, S. et al

in Food Chemistry (2011), 128(4), 895-901

The chemical composition and some functional properties of the dried "Ulva lactuca" algae, collected from the littoral between the Taboulba and Sayada area, were determined. The dried "U. lactuca" algae ... [more ▼]

The chemical composition and some functional properties of the dried "Ulva lactuca" algae, collected from the littoral between the Taboulba and Sayada area, were determined. The dried "U. lactuca" algae were investigated for their soluble, insoluble and total dietary fibre content, mineral amount, amino acid and fatty acid profiles, swelling capacity (SWC), water holding capacity (WHC) and oil holding capacity (OHC). Results showed that "U. lactuca" alga powder was characterised by a high content of fibres (54.0%), minerals (19.6%), proteins (8.5%) and lipids (7.9%). The neutral fibres contain hemicellulose (20.6%), cellulose (9.0%) and lignin (1.7%). The proteinic fraction analysis indicated the presence of essential amino acids, which represent 42.0% of the total amino acids. The fatty acids profile was dominated by the palmitic acid, which represents about 60.0% of the total fatty acids, followed by oleic acid (16.0%). The study of the functional properties proved that SWC, WHC and OHC of this alga varied with temperatures and that were comparable to those of some commercial fibre rich products. (C) 2011 Elsevier Ltd. All rights reserved. [less ▲]

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See detailKinetic of the hydrolysis of pectin galacturonic acid chains and quantification by ionic chromatography
Garna, H.; Mabon, N.; Nott, Katherine ULg et al

in Food Chemistry (2006), 96(3), 477-484

These experiments were designed to develop a rapid, repeatable and accurate analysis method for the quantification of galacturonic acid of pectins. Different pectin hydrolysis procedures (chemical and ... [more ▼]

These experiments were designed to develop a rapid, repeatable and accurate analysis method for the quantification of galacturonic acid of pectins. Different pectin hydrolysis procedures (chemical and enzymatic) were carried out with H2SO4, TFA and HCl at different acid concentrations (0.2, 1 and 2 M) and temperatures (80 and 100 degrees C). Enzymatic and combined chemical and enzymatic hydrolysis of pectin were also studied. A acid hydrolysis under drastic conditions (100 degrees C) is insufficient for complete hydrolysis and results in low recovery of galacturonic acid residues. Mild chemical hydrolysis (0.2, 1 and 2 M H2SO4 72 h at 80 degrees C) is also insufficient for complete depolymerization. Its main advantage is cleavage of the galacturonic acid chains into oligomeric forms without any degradation within 72 h of hydrolysis. However, enzymatic hydrolysis with VL9 for 2 h at 50 degrees C and combined chemical and enzymatic hydrolysis (0.2 M TFA at 80 degrees C for 72 h and VL9) give high recovery of this acid. Analysis of the liberated sugar residue by HPAEC allows us to determine the galacturonic acid composition of this polysaccharide accurately with high selectivity and sensitivity in one assay without the need for derivatization. (c) 2005 Elsevier Ltd. All rights reserved. [less ▲]

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See detailNew method for a two-step hydrolysis and chromatographic analysis of pectin neutral sugar chains
Garna, H.; Mabon, N.; Wathelet, Bernard ULg et al

in Journal of Agricultural and Food Chemistry (2004), 52(15), 4652-4659

A new method for the determination of the main neutral sugars in pectin has been developed. The sample preparation involves a mild chemical attack followed by an enzymatic hydrolysis. The completeness and ... [more ▼]

A new method for the determination of the main neutral sugars in pectin has been developed. The sample preparation involves a mild chemical attack followed by an enzymatic hydrolysis. The completeness and nondestructive character of the method are demonstrated by comparison of the results obtained with different acids such as H2SO4, HCI, and trifluoroacetic acid (TFA) at different concentrations (2, 1, or 0.2 M) at two temperatures (80 or 100 degreesC). The chemical hydrolysis of pectin neutral sugar chains with strong acid (1 or 2 M) and high temperature (100 degreesC) shows that the liberation of the pectin sugars is not realized at the same rate for each sugar. Different optimum conditions are thus obtained. However, the chemical pectin hydrolysis with 0.2 M TFA at 80 degreesC is characterized by the liberation of pectin neutral sugar side chains without any degradation within 72 h of hydrolysis. Under these conditions, the liberation of some pectin sugars, essentially galactose, glucose, and rhamnose, was not complete. An enzymatic hydrolysis is necessary to obtain a complete release of all the sugars. The combination of the two treatments, a chemical hydrolysis realized with diluted acid (0.2 M) for 72 h at low temperature (80 degreesC) on one hand and an enzymatic hydrolysis on the other hand, allow a total liberation of pectin sugars. The quantitative analysis of the carbohydrates is realized with accuracy, high selectivity, and sensitivity with high-performance anion-exchange chromatography with pulsed-amperometric detection. The sugars can be analyzed without any derivatization with a limit of quantification of 0.1 mM. [less ▲]

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See detailCombined enzymatic hydrolysis and HPAEC method for simultaneous analysis of galacturonic acid and neutral sugars of pectin.
Garna, H.; Mabon, N.; Wathelet, Bernard ULg et al

in Communications in Agricultural and Applied Biological Sciences (2003), 68(2 Pt A), 297-300

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