Influence of soy protein’s structural modifications on their microencapsulation properties: a-tocopherol microparticles preparation

Enzymatic and chemical modifications of soy protein isolate (SPI) were studied in order to improve SPI properties for their use as wall material for a-tocopherol microencapsulation by spray-drying. The structural modifications of SPI by enzymatic hydrolysis and/or N-acylation were carried out in aqueous media without any use of organic solvent neither surfactant. Emulsions from aqueous solutions of native or modified SPI and hydrophobic a-tocopherol, were prepared and spray-dried to produce a-tocopherol microparticles. The effect of protein modifications and the influence of the core/shell ratio on both emulsions and microparticles properties were characterised. The obtained results demonstrated that oil-in-water emulsions prepared with modified proteins had lower droplet size (0.5-0.9 μm) and viscosity (3.6-14.8 mPa×s) compared to those prepared with native proteins (1.1 μm and 15.0 mPa×s respectively). Efficiency of oil retention decreased after protein hydrolysis from 79.7 to 38.9%, but the grafting of hydrophobic chain by acylation improved efficiency of a-tocopherol retention up to 94.8%. Moreover, higher emulsion viscosity, particle size and process efficiency were observed with the increase of a-tocopherol amount

Vegetable proteins in microencapsulation: a review of recent interventions and their effectiveness

Proteins from vegetable seeds are interesting for research at present because they are an abundant alternative to animal-based sources of proteins and petroleum-derived polymers. They are a renewable and biodegradable raw material with interesting functional and/or physico-chemical properties. In microencapsulation, these biopolymers are used as a wall forming material for a variety of active compounds. In most cases, two techniques of microencapsulation, spray-drying and coacervation, are used for the preparation of microparticles from vegetable proteins. Proteins extracted from soy bean, pea and wheat have already been studied as carrier materials for microparticles. These proteins could be suitable shell or matrix materials and show good process efficiency. Some other plant proteins, such as rice, oat or sunflower, with interesting functional properties could be investigated as potential matrices for microencapsulation

Étude et fonctionnalisation de protéines végétales en vue de leur application en microencapsulation

Les protéines extraites des végétaux sont des matériaux relativement peu coûteux, non toxiques, biocompatibles et biodégradables. Elles représentent une bonne alternative aux protéines d origine animale et aux polymères dérivés du pétrole. Dans le cadre de cette étude, les protéines extraites de graines de soja et de tournesol ont été utilisées en tant que matériaux enrobants pour la microencapsulation de la matière active hydrophobe (a-tocophérol) ou hydrophile (acide ascorbique) par le procédé d atomisation. Les protéines de soja sont largement utilisées dans les applications alimentaires et non-alimentaires, notamment en microencapsulation. Elles sont donc étudiées dans ce travail comme matériau enrobant de référence. Les protéines de tournesol n ont quant à elles pas d application industrielle concrète, si ce n est sous la forme de tourteaux dans l alimentation animale. C est pourquoi il nous semble pertinent de trouver des nouvelles voies de valorisation pour ce coproduit d origine agricole. Plusieurs modifications des protéines, telles que l hydrolyse enzymatique, l acylation, la réticulation enzymatique et la cationisation ont été étudiées dans le but d améliorer les propriétés encapsulantes du matériau enrobant. Dans le contexte de la chimie verte, toutes les modifications ont été effectuées sans utilisation de solvants organiques ni de catalyseurs chimiques. L influence des modifications chimiques et enzymatiques des protéines, et des paramètres du procédé (pression d homogénéisation, ratio matériau enrobant/matière active et concentration en protéines) sur les différentes caractéristiques des préparations liquides et des microparticules (viscosité, taille des gouttelettes dans le cas des émulsions, morphologie et taille des microparticules), ainsi que sur les paramètres liés au procédé d atomisation (rendement et efficacité de microencapsulation) a été particulièrement étudiée au cours de ce travail. Les résultats obtenus confirment que l extrait protéique de tournesol est tout à fait pertinent comme matériau enrobant et permet d obtenir des efficacités de microencapsulation significativement plus élevées par rapport à celles obtenues avec l extrait protéique de soja.Proteins extracted from vegetables are relatively low-cost, non-toxic, biocompatible and biodegradable raw materials. They represent a good alternative to animal-based proteins and petroleum-extracted polymers. In this study, proteins derived from soybean and sunflower seeds were used as wall materials for microencapsulation of hydrophobic ( -tocopherol) or hydrophilic (ascorbic acid) active material by spray-drying technique. Soybean proteins are widely used in food and non-food applications, especially in microencapsulation. They were studied in this work as wall material of reference. Sunflower proteins are not actually used in industrial application, but only in the form of oil-cake for animal feeding. That s why new ways of valorization of this agricultural by-product should be investigated. Several proteins modifications such as enzymatic hydrolysis, acylation, cross-linking and cationization were studied in order to improve encapsulating properties of wall material. In the context of green chemistry, all the modifications and preparations were performed without use of organic solvents and chemical catalysts. The effect of protein chemical and enzymatic modifications, and process parameters (homogenization pressure, wall/core ratio and protein concentration) on different characteristics of liquid preparations and microparticles (viscosity, emulsion droplet size, microparticle size and morphology) and on parameters related to the spray-drying process (yield and efficiency of microencapsulation) was particularly investigated in this study. The obtained results confirmed that sunflower proteins are quite suitable as encapsulating agent and provide the microencapsulation efficiencies significantly higher compared to those obtained with soy proteins.TOULOUSE-INP (315552154) / SudocSudocFranceF

Comparative study of encapsulation of vitamins with native and modified soy protein

Microencapsulation of hydrophobic (α-tocopherol) and hydrophilic (ascorbic acid) vitamins by native (non-modified) and modified soy protein isolate (SPI) was carried out using a spray-drying technique. Proteins' functional properties were modified by acylation and cationization reactions in aqueous alkaline media. The results obtained demonstrated that SPI modification resulted in decreased emulsion droplet size and viscosity. All preparations with ascorbic acid (AA) had lower viscosity and microparticle size than those with α-tocopherol (T). Moreover, grafting of fatty acid chains to SPI by acylation improved its amphiphilic character and affinity with hydrophobic substances. Thus, the microencapsulation efficiency of T was increased from 79.7% to 94.8% and the microencapsulation efficiency of AA was reduced from 91.8% to 57.3% compared to native SPI. Conversely, attachment of quaternary ammonium cationic groups to proteinic chains by cationization, increased SPI solubility and favored the AA microencapsulation. This study illustrated that an appropriate modification of SPI can improve the microencapsulation efficiency of suitable active cores

The effect of vegetable protein modifications on the microencapsulation process

The use of soy proteins (SoyP) and sunflower proteins (SunP) in the microencapsulation by spray-drying technique of α-tocopherol (T) with a core/wall ratio of 2/1 was studied. SoyP and SunP were used as wall material in an unmodified and modified state. The enzymatic (hydrolysis and cross-linking) and chemical (acylation and cationization) modifications were carried out on vegetable proteins in order to improve their encapsulating properties. The results obtained demonstrated that in the native state, SunP showed higher retention efficiency for T microencapsulation (92.6%) compared to SoyP (79.7%), which could be connected to the different composition of protein extracts. Hydrolysis, acylation and cationization of protein resulted in reduced emulsion viscosity. The retention efficiency of T was improved up to 94.8–99.5% after protein acylation, which was attributed to improved affinity between core and wall material

Immunophénotypage sanguin dans les lymphomes malins non-hodgkiniens B (évaluation de la sensibilité et spécificité dans l'aide au diagnostic des stades IV médullaires )

La stadification des lymphomes malins non hodgkiniens B (LMNH-B) est un critère fondamental au diagnostic. D'après la classification d'Ann Arbor modifiée, l'envahissement de la moelle osseuse classe le lymphome en stade IV. Les LMNH de stade IV bénéficient de thérapeutiques plus agressives que les stades localisés (I ou II). L'envahissement de la moelle osseuse par les cellules lymphomateuses est apprécié sur une biopsie ostéomédullaire, dont l'interprétation est très dépendante de la qualité du prélèvement (taille de la biopsie, expérience du praticien, tolérance à la douleur du patient...). Une taille de biopsie supérieureà 20 mm devrait être systématique. Nous avons étudié 159 cas de LMNH-B au diagnostic et évalué de façon concomitante l'envahissement médullaire et le phénotype lymphocytaire sur sang périphérique par cytométrie en flux (CMF). Nous avons pu établir sur cette série la sensibilité et la spécificité de l'immunophénotypage sanguin en tant qu'outil de diagnostic. Afin de caractériser au mieux les populations lymphomateuses, nous avons préalablement étudié des échantillons de sang provenant de sujets sains, ainsi que de patients porteurs de maladies non hématologiques sans perturbation de l'hémogramme. Nous avons pu établir des profils d'expression des antigènes des antigènes de surface (CD) étudiés et mettre en évidence des anomalies (sur ou sous expression) dans la plupart des lymphomes étudiés. En corrélant les résultats de CMF à ceux des BOM, nous avons pu établir que la spécificité de l'immunophénotypage sanguin est égale à 100%. La sensibilité est variable selon le type de lymphome (de 70 à 100%) et est probablement liée à la capacité des lymphocytes anormaux à circuler dans le sang périphérique. Nous avons pu conclure que la CMF est un élément diagnostic fondamental, dont la spécificité excellente permet de se passer du recours systématique à la BOM pour classer le lymphome en stade IV. Dans notre étude environ 30% des BOM auraient pu être évitées.BORDEAUX2-BU Santé (330632101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Caractéristiques des leucémies lymphoides chroniques avec trisomie 12

BORDEAUX2-BU Santé (330632101) / SudocSudocFranceF

Influences des UV sur le vieillissement d'un bitume modifié par n Styrène/Butadiene/Styrene : Comparaison entre un vieillissement de laboratoire et un vieillissement sur site

During the service life in a pavement, neat bitumen and modified bitumen age as the result of the mixing with aggregates, the process of laying, the climatic conditions and the traffic. Laboratory methods for simulating the short-term and long-term ageing (RTFOT and PAV, respectively) are standardized. None of them takes into account the influence of UV radiations. In the particular case of a pavement located in south France, a comparison is drawn through Fourier Transformed InfraRed (FTIR) analysis. Three types of ageing are compared: the standard simulated ageings, the actual on site ageing after 12 and 26 months of road service and the ageing when UV exposure in a weathering oven follows RTFOT simulation. According to carbonyle function evolution by FTIR spectroscopy, this work shows that for all tested binders, the same ageing level as the one simulated by PAV is reached in a few hours when a thin film of binder is submitted to UV exposure after RTFOT. It is also to be noted that the level of the on site ageing of a SBS Polymer modified Bitumen (PmB) reaches the simulated PAV ageing after 12 months of pavement life

Influences des UV sur le vieillissement d'un bitume modifié par n Styrène/Butadiene/Styrene : Comparaison entre un vieillissement de laboratoire et un vieillissement sur site

During the service life in a pavement, neat bitumen and modified bitumen age as the result of the mixing with aggregates, the process of laying, the climatic conditions and the traffic. Laboratory methods for simulating the short-term and long-term ageing (RTFOT and PAV, respectively) are standardized. None of them takes into account the influence of UV radiations. In the particular case of a pavement located in south France, a comparison is drawn through Fourier Transformed InfraRed (FTIR) analysis. Three types of ageing are compared: the standard simulated ageings, the actual on site ageing after 12 and 26 months of road service and the ageing when UV exposure in a weathering oven follows RTFOT simulation. According to carbonyle function evolution by FTIR spectroscopy, this work shows that for all tested binders, the same ageing level as the one simulated by PAV is reached in a few hours when a thin film of binder is submitted to UV exposure after RTFOT. It is also to be noted that the level of the on site ageing of a SBS Polymer modified Bitumen (PmB) reaches the simulated PAV ageing after 12 months of pavement life

Using of native and modified soy proteins as biopolymers for a-tocopherol microencapsulation

National audienc