Structure et proprietes de pentosanes hydrosolubles de la farine de ble

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Pulsed laser ablation: A new approach to reveal wheat outer layer properties

International audienceA new methodology based on pulsed lasers has been developed in order to estimate wheat outer layer mechanical properties without sample preparation. Laser experiments were carried out with an Argon Fluoride ( l=193 nm) excimer laser source delivering pulses of 15 ns duration. Wheat grains from two cultivars were irradiated by single laser pulses with a quasi-uniform irradiation and two .uences (2.5 and 5 J cm -2). The ablation .ux was characterized by environmental scanning electron microscopy before measuring the removed material on cross-sections observed by confocal scanning laser microscopy. Speci.c image treatment was carried out to obtain the ablation .ux (amount of removed matter per pulse). Pericarp, seed coat and aleurone layer were gradually ablated under the laser conditions used in this work. Their ablation thresholds were different and could be related to tissue cohesion. Specific behaviour of seed coat layer (8 mm) could be emphasised with this technique. Pulsed laser ablation could be a potential methodology to reveal indirectly wheat grain layer cohesion

Electrostatic properties of wheat bran and its constitutive layers: Influence of particle size, composition, and moisture content

J. Food Eng. ISI Document Delivery No.: 432LE Times Cited: 15 Cited Reference Count: 44 Hemery, Youna Rouau, Xavier Dragan, Ciprian Bilici, Mihai Beleca, Radu Dascalescu, Lucian European Commission in the Communities Framework Program [FOOD-CT-2005-514008]; Poitou-Charentes Regional Council; European Union The authors thank G. Maraval for the preparation of the samples, T.-M. Lasserre for help with the biochemical analyses, and S. Das for helpful discussion. They also gratefully acknowledge the valuable experimental help given by R. Darracq, G. Paillet, W. Pillet, T. Rey-Vigneau, and N. Vincent. This work was supported in part by the Poitou-Charentes Regional Council and by the European Union, within the framework of ERASMUS program for Student and faculty mobility. This work was also financially Supported by the European Commission in the Communities Framework Program, Project HEALTHGRAIN (FOOD-CT-2005-514008). This publication reflects the author's views and the Community is not liable for any use that may be made of the information contained in this publication. Elsevier sci ltd OxfordInternational audienceBran is the by-product of white flour and is composed of distinct adhesive tissues with aleurone and pericarp being the most significant. The present work pointed out the good potential of using electrostatic separation as a bran-fractionation method to produce nutritionally interesting food ingredients. The tribo- and corona-charging behavior of ground bran, an aleurone-rich fraction, and a pericarp-rich fraction were characterized, and the influence exerted by the composition, particle size. and moisture content was determined. The tribo-charging experiments showed that the opening of the aleurone cells after grinding modified the particles surface composition, and thus the samples charging behavior. The cell walls of aleurone and pericarp fractions displayed different tribo-charging characteristics, suggesting that by designing an appropriate tribo-charging device, these two bran layers might be separated. The behavior of the samples after corona-charging was found to be highly influenced by their Moisture content. Dried samples were all found to behave like insulators, whereas when the materials were not dried. the pericarp-rich fraction behaved like a conductor while the fine aleurone-rich fraction behaved like an insulator, probably due to the presence of lipids at the particles surface. These characteristics could also be exploited for the development of another electrostatic separation process

Effect of pectic substances on prolactin and growth hormone secretion in the ewe and on the induction of casein synthesis in the rat

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Formation of phenolic microbial metabolites and short-chain fatty acids from rye, wheat, and oat bran and their fractions in the metabolical in vitro colon model

International audienceRye bran and aleurone, wheat bran and aleurone, and oat bran and cell wall concentrate were compared in their in vitro gut fermentation patterns of individual phenolic acids and short-chain fatty acids, preceded by enzymatic in vitro digestion mimicking small intestinal events. The formation of phenolic metabolites was the most pronounced from the wheat aleurone fraction. Phenylpropionic acids, presumably derived from ferulic acid (FA), were the major phenyl metabolites formed from all bran preparations. The processed rye, wheat, and oat bran fractions contained more water-extractable dietary fiber (DF) and had smaller particle sizes and were thus more easily fermentable than the corresponding brans. Rye aleurone and bran had the highest fermentation rate and extent probably due to high fructan and water-extractable arabinoxylan content. Oat samples also had a high content of water-extractable DF, beta-glucan, but their fermentation rate was lower. Enzymatic digestion prior to in vitro colon fermentation changed the structure of oat cell walls as visualized by microscopy and increased the particle size, which is suggested to have retarded the fermentability of oat samples. Wheat bran was the most slowly fermentable among the studied samples, presumably due to the high proportion of water-unextractable DF. The in vitro digestion reduced the fructan content of wheat samples, thus also decreasing their fermentability. Among the studied short-chain fatty acids, acetate dominated the profiles. The highest and lowest production of propionate was from the oat and wheat samples, respectively. Interestingly, wheat aleurone generated similar amounts of butyrate as the rye fractions even without rapid gas production