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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Investigation into interactions between emulsifiers and wheat starch/wheat flour

Ahmed, Anikka Susan January 1900 (has links)
Master of Science / Department of Grain Science and Industry / Yong-Cheng Shi / Jon M. Faubion / One long-term goal of cereal science research is to increase the shelf life of baked products and one approach to that goal has been the use of emulsifiers. Emulsifiers are surface-active agents, some of which improve specific properties of baked products. Two emulsifiers, sodium stearoyl lactylate (SSL) and oleyl lactylic acid (OLA) are similar in structure, the difference being the acid moiety: stearic versus oleic acid. Widely researched, SSL has found many uses in baked products. However, how OLA interacts with starch/flour in baked products or how that interaction affects product quality is not well understood. The objective of this study was to understand the interactions between normal wheat starch and these emulsifiers, as well as the differences between SSL and OLA in those regards. The effects of the two emulsifiers on the pasting properties of wheat starch and wheat flour were determined using a MicroViscoAmylograph. Heating at 6oC/min with increased emulsifier concentration (0-2%) resulted in increased hot paste viscosity and apparent interaction of both emulsifiers with wheat starch. Solid content affected both maximum hot and final viscosity. OLA produced increased maximum hot and final viscosities with increased starch concentration and emulsifier concentrations. For wheat flour, higher concentrations of SSL reduced both maximum hot paste and final viscosities. OLA behaves differently with wheat flour. At lower flour concentrations, higher concentrations of OLA reduced maximum hot viscosity. The effects of SSL on starch were affected by an increased heating and cooling rate (10oC/min). Heating stage microscopic analysis revealed that the presence of emulsifiers inhibited granular swelling beyond the normal gelatinization temperature (65oC) in both starch and flour systems. OLA’s effect in this respect was greater than that of SSL. Complex formation between emulsifiers and wheat starch and wheat flour was determined using differential scanning calorimetry (DSC) and X-ray diffraction (XRD). For isolated wheat starch and hard wheat flour, DSC and XRD indicated that OLA complexes to a greater extent than does SSL. For flour, XRD indicated no difference exhibited in the interaction of the emulsifiers with the flours. KEYWORDS: Emulsifiers, Starch, Wheat flour
2

Effects of emulsifiers on properties of microemulsions and polymeric emulsions

Lin, Ching-Sheng January 1994 (has links)
No description available.
3

Evaluation of different types of fats for use in high-ratio layer cakes

Zhou, Jianmin January 1900 (has links)
Master of Science / Department of Grain Science and Industry / Jon M. Faubion / Charles E. Walker / Shortening is a major ingredient used in high-ratio layer cakes. Plastic shortenings are most commonly used by the U.S. baking industry, but high levels of trans- or saturated fats cause health concerns. Compared to plastic shortenings, liquid shortenings could significantly reduce the dependence on high melting point fats and the emulsifiers used would enhance the shortening’s functionality. The objective of this research was to compare the influence of different types of fats on the texture and shelf-life of high-ratio layer cakes. Cakes were baked with soybean oil to evaluate the function of three emulsifiers (PGMS, GMS, and Lecithin) on layer cake quality, including volume, cake score, interior visual texture (C-Cell), and firmness (Voland-Stevens). An optimum emulsifier combination was chosen (PGMS 1.8%, GMS 1.0% and Lecithin 0.8%) for addition to the liquid oil. Four groups of layer cakes were baked using: plastic shortening, liquid shortening, liquid oil, or liquid oil plus emulsifier combination. Cake performance and firming over-time were evaluated. The liquid shortening provided the best fresh cake characteristics and cake firmness performance. Liquid oil combined with a combination of added emulsifiers performed very similar in terms of firmness, as did the liquid shortening. This indicated that emulsifiers played an important role on the improvement of cake firmness shelf-life.
4

Maximizing the use of food emulsifiers

Baker, Steven R. January 1900 (has links)
Master of Science / Department of Animal Sciences and Industry / J. Scott Smith / Emulsifiers have been and remain highly functional ingredients in the food industry. Emulsifiers contain both hydrophilic and lipophilic parts, resulting in their ability to be useful in foods at very low levels. However, knowledge of why emulsifiers work and how to use them most effectively is reserved for the few scientists who specialize in the discipline. Therefore, a comparison of current emulsifier theory with known emulsifier usage in the industry is beneficial to all who use these ingredients. Current emulsifier theory effectively describes how emulsifiers behave in food systems. Emulsion theory details how emulsifiers facilitate the formation and stability of emulsions through study of the kinetics of food systems. Emulsion theory further relates the ability of emulsifiers to interact with other substances in a food system. The main interactions concerning emulsifiers are their ability to form mesophases with water, to strengthen or weaken protein interactions, to form complexes with starches, and to promote or subdue fat crystallization. However, industrial applications of emulsifiers indicate areas where exceptions to theory exist. While emulsion theory has been found to effectively describe the individual interactions and functions in food, the simplicity of the models indicates that complex food system models are still needed to truly understand how to maximize the functionality of emulsifiers.
5

Avaliação da atividade lipolítica de fungos filamentosos da costa brasileira. / Evaluation of the lipolytic activity of filamentous fungi from the brazilian coast.

Garcia, Alexandre Kopte 25 February 2011 (has links)
A produção de compostos biologicamente ativos por micro-organismos marinhos tem atraído crescente interesse de biotecnólogos e microbiologistas nas últimas décadas. No presente trabalho 162 isolados de fungos filamentosos recuperados de amostras de água do mar e de dez diferentes macro-organismos marinhos foram avaliados quanto a produção de lipases pelo método de High Throughput Screening (HTS). Destes, 45 isolados tiveram a produção de lipases confirmada individualmente. A atividade lipolítica foi quantificada, e os resultados sugerem que fungos filamentosos oriundos de ambientes marinhos tem maior potencial para produção de lipases estáveis em pH alcalino. Entre estes, Fusarium sp. CBMAI 1227, Aspergillus parasiticus CBMAI 1228 e Trichoderma sp. CBMAI 1229 apresentaram atividade expressiva e de interesse biotecnológico em pH 8,0 (23,1, 12,7 e 12,2 U respectivamente). Os resultados deste trabalho demonstram o potencial dos fungos provenientes de ambiente marinho para aplicações biotecnológicas, e estimulam novos estudos envolvendo lipases. / The production of biologically active compounds by marine microorganisms has been drawing increasing interest of biotechnologists and microbiologists in the last decades. In the present work 162 filamentous fungi isolates recovered from water samples and ten different marine macroorganisms were evaluated for the production of lipases by the method of High Throughput Screening (HTS). Out of those, 45 had the lipase production individually confirmed. The lipolytic activity was quantified, and the results suggest that marine-derived filamentous fungi have a greater potential for the production of lipases stable under alkaline pH. Among these, Fusarium sp. CBMAI 1227, Aspergillus parasiticus CBMAI 1228 and Trichoderma sp. CBMAI 1229 showed expressive and biologically interesting activity in pH 8,0 (23,1, 12,7 and 12,2 U/min respectively). The results of the present work show the potential of marine-derived fungi in biotechnological applications, and stimulate new studies involving lipases.
6

Uticaj sastava i uloge lipida brašna u procesu izrade hleba / THE INFLUENCE OF COMPOSITION AND ROLE OF FLOUR LIPIDS IN BREADMAKING PROCESS

Filipović Nada 09 February 1998 (has links)
<p>Apstrakt je obrađen tehnologijama za optičko prepoznavanje teksta (OCR)</p><p>Utvrdeni su sastav i količine nepolarnih i polarnih lipida kao i lipida iz skroba u pojedinim fazama izrade hleba na dva uzorka bra&scaron;na od kvalitetne p&scaron;enice. Takode su odredene promene i prelazi lipidnih sastojaka pod uticajem fizičkih, mehaničkih i toplotnih delovanja tokom tehnolo&scaron;kog postupka.<br />Na osnovu sastava masnih kiselina u lipidnim jedinjenjima razdvojenim tankoslojnom hromatografijom i računa verovatnoće utvrđen je njihov najverovatniji sastav.<br />Iz ekstrakta nepolarnih lipida bra&scaron;na kvantitativno je identifikovano preko 60 %, a iz hleba preko 40 % lipidnih jedinjenja (ASG, MG i TG).<br />U ekstraktima polarnih lipida identifikovano je preko 60 % jedinjenja (DGMG, DGDG, MGMG i MGDG) a u lipidima unutar skroba zastupljeni su samo LPI i NAPE.</p><p>U ekstraktima lipida i u lipidnim jedinjenjima identifikovano je oko 98 % masnih kiselina a najveći udeo je lilinolne kiseline.<br />Takođe je ispitan uticaj načina dodavanja tri vrste komercijalnih emulgatora u pojedinim fazama izrade testa na kvalitet hleba.<br />Delovanje komercijalnih emulgatora u testu i hlebu zavisi od vrste, sastava i i količine emulgatora kao i od kvaliteta bra&scaron;na kome se dodaje. Pobolj&scaron;avajući efekti se mogu postići samo ako se emulgator dozira na početku zamesa ili tokom razvoja testa.<br />Rezultati ovog rada su pomogli da se bliže odredi mesto i uloga lipidnih materija bra&scaron;na u procesu izrade hleba kao i interakcija lipida bra&scaron;na sa komercijalnim emulgatorima.</p> / <p>Abstract was processed by technology for Optical character recognition (OCR).</p><p>Composition and quantities of nonpolar, polar and starch lipids were identified in different stages of bread making process. Changes and translocations of lipid compounds influenced by physical, mechanical and heat treatment during the technological process were determined, too.<br />Based on fatty acid composition in different lipid compounds separated by TLC and on probability calculation, the most probable composition of them was est imated.<br />In nonpolar lipid extracts of flour, over 60 % and in bread over 40 % of lipid compounds were identified (ASG, MG and TG).<br />In polar lipid extracts over 60 % of lipid compounds were identified (DGMG,<br />DGDG, MGMG and MGDG) but in starch lipids only LPI and NAPE were present.<br />In lipid extract and lipid compounds about 98 % of fatty acids were identi- fied with the greatest shane of linoleic acid.<br />The influence of adding three commercial emulsifiers in different stages of dough making on bread quality was also invest igated.<br />Acting of commercial emulsifiers in dough and bread depends on their type, composition and quantity, as well as, on flour quality. Improving effects can be achieved only if emulsifiers ane added at the beginning of mixing stage or during dough development.<br />These results comprise to better understanding of the lipid compounds role, the place of their acting in breadmaking process as well as their interaction with commercial emulsifiers.</p><p>&nbsp;</p>
7

Obtenção de manoproteína e β-glucana de levedura descartada em cervejaria com potencial para aplicação em alimentos

Araújo, Vilma Barbosa da Silva 11 February 2014 (has links)
Made available in DSpace on 2015-04-17T14:49:37Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1723546 bytes, checksum: d6ebd3071471297d43af6b6d405af8d9 (MD5) Previous issue date: 2014-02-11 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Yeasts of the genus Saccharomyces spp. are used as biotechnological tool in brewery and after five fermentative production processes; they are discarded by the beer industry. The cell wall of yeasts is mainly composed of β - glucan, which is a glucose homopolymer capable of changing the immune response in the host, and by manoproteins (MP), which have recognized emulsifying properties. The aim of the present study was to obtain these two cell wall fractions of discarded yeast employing an additional step to obtain MP in a process applicable to the extraction of β - glucan. The fractions obtained were characterized and MP was evaluated for potential for application as an emulsifier in mayonnaise formulations. From the cell wall of yeasts on dry basis, the MP and β glucan yield was 4.16% and 10 %, respectively. The residual moisture of β - glucan was 4.9 ± 0.1 % and MP was 3.9 ± 0.9 % and no changes in this parameter were observed during 28 days of storage in bi-oriented polypropylene packs (BOPP) at 10°C, 25°C or 40° C. The SDS-PAGE profile of MP showed proteins with molecular weight of 58 kDa and 64 kDa, and the highest content of constituent amino acids was observed for valine (8.9%), aspartic acid (8.2%) and leucine (6.9%). Each 100 g of mayonnaise prepared with MP at concentrations of 0.6%, 0.8 % and 1.0 % contained, on average, 25 ± 0.27 g moisture, 1.6 ± 0.10 g ash, 2.4 ± 0.04 g protein, 56 g ± 0.41 lipid and 14 ± 0.12 g carbohydrates, and no changes in attributes aroma, color, flavor and texture were observed in the study period (28 days). The results showed applicability of the method proposed for obtaining β -glucan and MP and suggest that MP has potential for application as bioemulsifier in foods, particularly in mayonnaise formulations. / Leveduras do gênero Saccharomyces spp. são empregadas como ferramenta biotecnológica, na produção de cerveja e após em média cinco processos fermentativos de produção, são descartadas pela indústria cervejeira. A parede celular de leveduras é formada principalmente pelas β-glucana, que são homopolímeros de glicose capazes de alterar a resposta imune no hospedeiro, e pelas manoproteínas (MP) que possuem reconhecidas propriedades emulsificantes. No presente estudo foi proposto obter estas duas frações da parede celular de levedura descartada em cervejeira empregando uma etapa adicional para obtenção da MP em um processo aplicável a extração da β-glucana. As frações obtidas foram caracterizadas e a MP avaliada quanto ao potencial para aplicação como emulsificante em formulações de maionese. A partir da parede celular de levedura em base seca, o rendimento da MP e da β-glucana foi de 4,16% e 10%, respectivamente. A umidade residual da β-glucana foi de 4,9 ± 0,1% e da MP foi de 3,9 ± 0,9% e não foram observadas alterações neste parâmetro durante 28 dias de armazenamento em embalagens de polipropileno bi-orientado (BOPP) a 10 °C, 25 °C ou 40 °C. O perfil de SDS-PAGE da MP evidenciou proteínas de peso molecular de 58 kDa e 64 kD e o maior teor de aminoácidos constituintes foi observado para a valina (8,9%), ácido aspártico (8,2%) e leucina (6,9%). Cada 100 g de maionese preparada com MP nas concentrações de 0,6%; 0,8% e 1,0% continham, em média, 25 ± 0,27g de umidade, 1,6 ± 0,10 g de cinzas, 2,4 ± 0,04 g de proteína, 56 ± 0,41 g de lipídeos e 14 ± 0,12 g de carboidratos, e não foram observadas alterações nos atributos aroma, cor, sabor, textura no período analisado (28 dias). Os resultados obtidos evidenciam aplicabilidade do método proposto para obtenção de MP e β-glucana e sugerem que a MP possui potencial para aplicação como bioemulsificante em alimentos, em especial em formulações de maionese.
8

Etude du fractionnement de graines entières oléo-protéagineuses pour l'obtention de fractions multifonctionnelles de type "émulsions actives" dans le domaine de la formulation cosmétique / Study of fractionation of oleoproteaginous seeds to obtain multifonctional type of active emulsion in the field of cosmetics development

Magimel, Alice 10 November 2016 (has links)
Ces travaux concernent l’étude du fractionnement de plantes régionales sélectionnées pour l’obtention de fractions multifonctionnelles de type « émulsions actives » à usage cosmétique afin de permettre la substitution des ingrédients de synthèse (SDS, sulfate de lauryle, éther de glycol, PEG…) et d’élaborer directement des formulations cosmétiques 100% végétal en totum de plante conservant les activités biologiques attendues et biolabelisables. Le choix des matières premières s’est porté sur des graines oléoprotéagineuses. En plus d’être des ressources renouvelables et facilement disponibles, aussi bien issues de l’agriculture conventionnelle que de l’agriculture biologique, elles présentent des compositions très variées. Les graines de chanvre, de colza, de cardon, de pastel et de lin ont été choisies du fait de leur complémentarité en composition en acides gras et en protéines. Des caractérisations physico-chimiques et fonctionnelles liées à leur fraction protéique en particulier ont permis d’obtenir des données fondamentales pour le développement et la compréhension des procédés d’extraction mis en jeu dans ces travaux. Le fractionnement aqueux des graines a été étudié en réacteur batch agité, puis le procédé a été étendu à un procédé continu, de type extrusion bi-vis plus largement exploré. Le fractionnement aqueux en réacteur thermo-mécanochimique (TMC) des graines oléoprotéagineuses entières, seules puis en mélanges a été mis en oeuvre, puis un actif polysaccharidique naturel a été introduit in situ par le biais de la phase aqueuse extractante afin d’obtenir des fractions enrichies en molécules d’intérêt et d’augmenter la stabilisation des émulsions obtenues. Les meilleurs résultats en termes de rendement et de qualité d’émulsions ont été obtenus avec les graines de colza entières et le mélange de graines entières chanvre/colza. Les différents types d’émulsions obtenus par le procédé TMC et leur comportement en fonction de différents paramètres ont été caractérisés en microscopie optique mais également par le biais de méthodes originales telles que la DSC ou la RMN à bas champs. Des premiers essais de valorisation des émulsions en formulation galénique pour la cosmétique ont été développés. / This PhD work studies the fractionation of selected regional plants in order to produce multifunctional "active emulsions"type fractions , for cosmetic purposes . This process allows the direct substitution of synthetic ingredients (SDS, lauryl sulfate, glycol ether, PEG ... ) and the development of cosmetic formulations in 100% vegetal plant totum, therefore maintaining the expected biological activities and organic qualifying properties. The choice of raw materials was directed to oilseeds. Not only are oilseed seeds renewable and readily available resources, both from conventional agriculture as well as organic farming, but they also have very different compositions. Hemp, rapeseed, cardoon, woad and flax were chosen because of their complementarity in terms of fatty acid and protein composition. Indeed, physico-chemical and functional characterization related to their protein fraction,have yielded fundamental data for the development and understanding of extraction processes involved in this work. The aqueous fractionation of seeds was studied in a stirred batch reactor and then extended to a continuous fractionation process : twin screw extrusion. This method has been more widely explored. The aqueous fractionation in thermomechano- chemical (TMC) reactor of whole oilseed seeds, one variety at a time and then mixed was implemented first. Then an active natural polysaccharide was introduced in situ through the extracting aqueous phase in order to produce enriched fractions in molecules of interest and to increase the stabilization of the emulsions thus obtained. The best results in terms of yield and quality of emulsions were obtained with the whole rapeseed and the mixture of whole hemp / rapeseed. The different types of emulsions obtained by the TMC process and their behavior under different parameters were characterized by optical microscopy but also through innovative methods such as DSC or NMR low fields. The first valuation tests of formulation in emulsions for cosmetics have been developed.
9

Avaliação da incorporação de emulsificantes sobre as propriedades de cristalização de gorduras industriais / Evaluation of emulsifiers addition on the crystallization properties of industrial fats

Domingues, Maria Aliciane Fontenele, 1983- 23 August 2018 (has links)
Orientador: Lireny Aparecida Guaraldo Gonçalves / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-23T10:13:31Z (GMT). No. of bitstreams: 1 Domingues_MariaAlicianeFontenele_D.pdf: 11965848 bytes, checksum: a162bec80fb4e8638934162b8e9b5d5b (MD5) Previous issue date: 2013 / Resumo: A cristalização de gorduras é um fator crítico associado à estruturação e propriedades de grande parte dos alimentos. No Brasil, as questões controversas acerca do papel dos ácidos graxos trans na alimentação ocasionaram modificações progressivas na legislação e no uso industrial de gorduras, levando à substituição das gorduras parcialmente hidrogenadas por gorduras interesterificadas, fracionadas ou blends. Considerando que este processo de substituição foi ampliando, os problemas de comportamento de cristalização devido à não adequação das novas frações gordurosas são inúmeros e agravados, principalmente, pelas diferenças climáticas regionais e condições de transporte e estocagem. Logo, a adequação da cinética de cristalização destas bases gordurosas é de extrema importância para que o uso das mesmas possa ser ajustado às limitações dos processos industriais e para melhorar o controle de etapas de processamento que envolva recristalização da fração gordurosa, garantindo a qualidade do produto final. Caso contrário, os tempos de processamento e equipamentos já padronizados precisam ser alterados segundo as características da gordura utilizada. Emulsificantes são aditivos funcionais de extrema importância na indústria de alimentos, que podem ser utilizados para controlar ou modificar as propriedades de cristalização da fase gordurosa. O estudo dos efeitos de emulsificantes em sistemas gordurosos é de grande interesse para o melhoramento de novas bases gordurosas com finalidades específicas, uma vez que propriedades apropriadas de cristalização são de difícil obtenção quando da ausência de ácidos graxos trans. O papel destes compostos como modificadores de cristalização em gorduras naturais e comerciais é pouco explorado, constituindo-se em um assunto inovador sob o ponto de vista da indústria de alimentos. Neste contexto, o objetivo deste trabalho foi avaliar o efeito da incorporação de ésteres de sorbitana e sacarose sobre as propriedades de cristalização da gordura interesterificada base soja, do óleo de palma e da fração mediana de palma (soft PMF). Estas gorduras industriais apresentam algumas limitações quanto a sua aplicação, especialmente relacionadas com determinadas propriedades, tais como: consistência e plasticidade dos produtos durante as etapas de produção e estocagem; propriedades sensoriais, como sensação de fusão na boca; estabilidade física, com respeito à formação ou sedimentação de cristais e exsudação de óleo; e aparência visual, a exemplo do brilho em chocolates e coberturas. Portanto, o presente trabalho mostra grande relevância para o setor produtivo de óleos e gorduras / Abstract: Fat crystallization is a critical factor associated with either structuring or properties of most foods. In Brazil, controversial issues about the role that trans fatty acid plays on food gave rise to progressive changes in the legislation as well as in the industrial use of fat, which leads to partial substitution of hydrogenated fat by interesterified, fractionated or blended fat. Considering that this substitution process was expanded, problems regarding crystallization behavior are countless and even aggravated because the new fat fractions are not adequate, mainly for regional climatic differences, transportation and storage conditions. Therefore, the crystallization kinetic inadequacy of such fatty bases is extremely important, so that their use can fit the industrial process limitation purposes and improve the control on processing stages that involve recrystallization of fat fractions, ensuring the quality of the final product. Otherwise, time processing and equipment already brought into line need to be changed according to the characteristics of the fat used. Emulsifiers are extremely important functional additives in food industry and can be used to either control or modify the crystallization properties in the fatty stage. The study of emulsifiers effects on fatty systems is of great interest to improve new fatty bases with specific purposes, since appropriate crystallization properties are difficult to obtain when trans fatty acid lacks. The role of these compounds as crystallization modifiers in natural and commercial fat is not much investigated, thus constituting an original subject under the food industry point of view. In this context, the aim of this study was to evaluate the effect of addition of sorbitan and sucrose esters on the crystallization properties of interesterified fat based soy, palm oil and palm median fraction (soft PMF). These industrial fats present some limitations regarding their application, especially related to certain properties, such as: product consistency and plasticity during the stages of production and storage; sensory properties like melting sensation in the mouth; physical stability with respect to crystal formation or sedimentation and oil exudation; and visual appearance, like the glint in chocolates and coatings. Therefore, this work shows highly relevant to the productive sector of oils and fats / Doutorado / Tecnologia de Alimentos / Doutora em Tecnologia de Alimentos
10

Evaluation et compréhension de la structure de l’émulsifiant et son impact sur les propriétés physiques, physico-chimiques et sensorielles d’émulsions cosmétiques / Evaluation and understanding of the emulsifiers structure and its impact on the physical, physicochemical and sensory properties of cosmetic emulsions

Terescenco, Daria 26 February 2018 (has links)
L’émulsifiant est une matière première largement utilisée dans les systèmes formulés de type émulsion. Grâce à sa structure chimique amphiphile, cette molécule diminue la tension interfaciale entre les deux liquides non miscibles qui composent une émulsion, ce qui augmente la stabilité du système dans le temps. En plus, à cause de sa structure, il peut former des cristaux liquides dans les systèmes formulés, ce qui impacte considérablement les propriétés physico-chimiques et applicatives des émulsions. Ce projet vise l’étude d’un tensioactif mixte naturel alkyl polyglucoside/alcool gras. Les propriétés de celui-ci ont été d’abord investiguées via la construction du diagramme de phase. Ainsi, il a été démontré que la variation de la concentration et du ratio alkyl polyglucoside/alcool gras dans l’émulsifiant mixte favorise le passage de solutions micellaires vers les cristaux liquides de types lamellaire ou hexagonale dans les systèmes étudiés. La maitrise des propriétés des systèmes binaires a permis, par la suite, de comprendre les métamorphoses subies par le système lorsqu’une phase grasse est incorporée. La structure chimique des émollients (présence des hétéroatomes) affecte l’organisation des cristaux liquides formés par les molécules amphiphiles. Par conséquent, en fonction de l’émollient utilisé, les propriétés microscopiques et macroscopiques des systèmes changent (taille et distribution des gouttelettes, profil rhéologique, thermique et de texture). Finalement, les propriétés applicatives des émulsions sont aussi affectées, comme cela a été montré via l’analyse sensorielle et les mesures biométriques in-vivo. / Emulsifier is a raw material widely used in formulated systems of emulsion type. Due to its amphiphilic chemical structure, this molecule decreases the interfacial tension between two immiscible liquids that form an emulsion, which increases the stability of the system over time. In addition, it can form liquid crystals in the formulated systems because of its structure and this has a considerable impact on the physicochemical and applicative properties of emulsions. The objective of this project is to study a natural alkyl polyglucoside/fatty alcohol mixed surfactant. Its properties were first investigated via the construction of the phase diagram. Thus, it has been shown that the variation of the concentration and of the ratio of alkyl polyglucoside/fatty alcohol in the mixed emulsifier favors the transition between the micellar solutions towards liquid crystals of lamellar or hexagonal type in the studied systems. Next, the mastering of the binary systems properties allowed understanding the metamorphoses undergone by the system when an oil phase is incorporated into it. The chemical structure of emollients (presence of heteroatoms) affects the organization of liquid crystals formed by the amphiphilic molecules. Therefore, depending on the emollient type, the microscopic and macroscopic properties of the systems change (droplet sizes and distribution, rheological, thermal and texture profile). Finally, the applicative properties of emulsions are also affected, as shown by sensory analysis and in-vivo biometric measurements.

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