The main objective of this study was to determine the effect of fruit ripeness and drying method on the oxidative stability and micro-component content of avocado oil extracted with supercritical carbon dioxide (SC-CO2). A secondary objective was to determine the effect of fruit ripeness, method of fruit drying and extraction method on the extractability of avocado oil with hexane and SC-CO2. For the oil extractability study, unripe and ripe avocado fruit pieces were either freeze-dried or oven-dried (80oC) and extracted with hexane or SC-CO2. For both extraction methods, oil yield was higher from ripe fruit than from unripe fruit. Scanning electron microscopy (SEM) indicated structural degradation during ripening, making the oil more available for extraction in ripe fruit. Oil from freeze-dried samples was in most cases more extractable than from oven-dried samples possibly through formation of rigid structures due to starch gelatinisation and dehydration and protein crosslinking around the oil cells during oven drying. Oil yield was higher with hexane than with SC-CO2 extraction because hexane is less selective, permeates the whole plant material and leads to a more complete extraction, while SC-CO2 may create paths of least resistance in the plant material where it moves preferentially, thus leading to a less complete extraction. For oxidative stability studies and micro-component characterisation, oil extractions were performed on an industrial scale SC-CO2. extractor. For all treatments (unripe freeze-dried, ripe freeze-dried, unripe oven-dried, ripe oven-dried), oil was divided into four fractions and analysed for fatty acid profile, peroxide value (PV), anisidine value (AV), free fatty acids (FFA), oxidative stability index (OSI), colour, tocopherol, sterol, chlorophyll, carotenoid and total unsaponifiable content. Oil from ripe, freeze-dried avocado had relatively lower levels of chlorophyll, carotenoids and tocopherols, than oil samples from the other treatments. This may be due to relatively higher lipoxygenase levels in ripe fruit which may bring about higher oxidative breakdown of these components. Also, the activity of lipoxygenase may be preserved under the lower temperature conditions of freeze-drying, but inactivated at high temperature during oven-drying. Intensity of blue and red on the Lovibond colour scale of all oil samples as well as chlorophyll and carotenoid content increased with progressive extraction. These pigments are presumably extracted in the latter stages of extraction because they are located in chloroplasts, chromoplasts and idioblast cells with thicker membranes than the parenchyma cells where triglycerides are located. Levels of total sterols, total tocopherols and their isomers did not show any specific trends with progressive extraction, which could be related to their location in cell membranes where they would be extracted concurrently with the triglycerides. Levels of total unsaponifiables were mostly higher in the first than the latter fractions. This could be due to the early elution of non-polar waxes which are highly soluble in SC-CO2 and highly available due to their location on the surface of the avocado skin. The fatty acid profile of the avocado oil was not influenced by the degree of ripeness or drying method and therefore did not affect the OSI. Oleic acid increased while linoleic acid decreased with progressive extraction. Compared to the changes observed in levels of some of the micro-components, the changes in fatty acid levels with progressive extraction were relatively small and the fatty acid profile alone could not explain the OSI of the oil. Oil from oven-dried avocado had lower PVs but higher AVs than oil from freeze-dried fruit indicating more advanced oxidative deterioration in oil from oven-dried samples than from freeze-dried samples. FFA levels were higher in oil from ripe, freeze-dried fruit. Levels of hydrolytic enzymes increase during fruit ripening and are preserved during freeze-drying while they are inactivated during oven-drying. FFA levels decreased with progressive extraction. Free fatty acids are very soluble in the SC-CO2 and due to their location on the surface of the plant material, they could be extracted early in the extraction. Oil from oven-dried fruit had relatively higher OSI compared to the other treatments. The OSI of all samples increased with progressive extraction. There was a significant negative correlation between FFA and OSI for both drying methods. AV correlated positively with OSI for oil from oven-dried fruit and negatively for oil from freeze-dried fruit. AV contributed the most to the prediction of OSI in oven-dried fruit, while FFA contributed the most in freeze-dried fruit. It was suggested that the high OSI of oil from oven-dried fruit, despite its high AV, may be due to the presence of compounds with high antioxidant activity in the oil formed through the high temperatures of the oven-drying process. Therefore, using multiple regression techniques, predictive models were developed to determine the effect of the micro-components on the oxidative stability of the oil. The OSI correlated positively with chlorophyll (0.83) and carotenoids (0.80). The models indicated that chlorophyll and carotenoids were the most important variables in predicting the oxidative stability of avocado oil extracted with SC-CO2. This might be due to the antioxidant effect of carotenoids and the possible formation of pheophytin and pyropheophytin, thermal breakdown products of chlorophyll, which exert antioxidant effects in oil. / Thesis (PhD (Food Science))--University of Pretoria, 2008. / Food Science / unrestricted

Thesis (PhD)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Maceration enzymes for the wine industry are preparations containing mainly pectinases, cellulases and hemicellulases, used during wine making to degrade the berry cell walls and release polyphenolic and aroma molecules to increase wine quality. These types of enzymes are also used for the harvesting of revenue-generating molecules from pomace (skins, pulp and seeds from grape processing waste), or as processing aids when used in the production of bioethanol. Grape berry cell walls are recalcitrant towards degradation, therefore knowledge about their structures and compositions, as well as how the application of enzymes modify these structures is essential in order to optimise these processes. The aim of this study was to extend current knowledge by using a mixture of existing and novel methodologies to study grape berry cell walls by focusing on the profiles of polymers present in the walls. Cell wall profiling techniques used in this study include the Comprehensive Microarray Polymer Profiling (CoMPP) method that employs monoclonal antibodies and Carbohydrate Binding Modules (CBM) which specifically recognise the polymers in the plant cell wall. With this method we measured the abundance of specific polymers and traced the fluctuation in their levels of abundance as influenced by external factors such as enzyme hydrolysis. The CoMPP method was coupled with monosaccharide profile analysis by GC-MS to determine the building blocks of the cell wall polymers, as well as with Infrared Spectroscopy to monitor the changes in the bulk chemistry profile. Data sets generated by the cell wall profiling methods were analysed with uni- and multivariate statistical methods to detect the major patterns in the data. This study highlighted the cell wall differences on the polymer level, in the berry skin cells of Pinotage grapes at different ripeness levels and how it changes during a standard wine fermentation, leading to the release of homogalacturonans and the exposing of arabinogalactan proteins. When maceration enzymes were added, further depectination was evident and the enzymes unravelled the cell wall of the ripe grapes. In overripe grapes no additional degradation could be observed due to maceration enzyme actions, presumably indicating that the endogenous grape enzymes already caused extensive degradation. When purified enzymes were incubated under buffered conditions with isolated skin cell walls from Pinotage grapes or with Chardonnay grape pomace, different levels of enzymatic hydrolysis were observed and defined. The sequence in which cell wall polymers were extracted, and the influence of specific enzymes in facilitating the extraction process, provided important information on the accessibility of specific cell wall polymers. Synergistic action between, for example an endo-polygalacturonase (EPG) and an endo-glucanase (EG) was demonstrated with CoMPP. This EPG and EG synergism was also demonstrated with a yeast strain (a Saccharomyces paradoxus x S. cerevisiae hybrid) fermented in a buffered pomace suspension. This yeast strain has a native EPG and was engineered to also express a recombinant EG from a genome integrated cassette. The cell walls isolated from the pomace after fermentation were unravelled and depectination took place, as evident from CoMPP data. The cell wall profiling techniques used in this study were proven to be fast and sensitive. It provided insights into the structure of grape cell walls and was used to evaluate the changes due to ripening, fermentation, enzymatic hydrolysis and a heat pre-processing treatment. In addition to the knowledge gained, we also demonstrated that these techniques can be used to evaluate different enzymes and enzyme combinations as well as the potential of microorganisms to degrade grape tissue. / AFRIKAANSE OPSOMMING: Maserasie ensieme vir die wynindustrie is ensiem mengsels wat hoofsaaklik pektinases, sellulases en hemisellulases bevat en word tydens wynbereiding gebruik om die druifkorrel se selwand af te breek, die polifenole en aroma molekules vry te stel en sodoende die wyn kwaliteit te verbeter. Hierdie soort ensieme word ook gebruik om inkomste-genererende molekules vanuit druiweprosesserings afval (doppe, pulp en pitte) te isoleer, en ook as prosesserings hulpmiddels in die produksie van bioetanol. Druifkorrel selwande is weerstandig teen ensiem afbraak en daarom is kennis oor die struktuur en samestelling van die selwand, asook hoe die selwand strukture deur die toediening van ensieme verander word noodsaaklik om sodoende hierdie prosesse te optimaliseer. Die doel van hierdie studie was om die huidige kennis uit te brei deur bestaande asook nuwe metodes te gebruik om die druifkorrel selwand te bestudeer met die fokus op die polimeerprofiel van die selwande. Selwand karakteriserings tegnieke wat in hierdie studie gebruik is sluit in die Comprehensive Microarray Polymer Profiling (CoMPP) metode wat monoklonale teenliggaampies en koolhidraat bindende modules (Carbohydrate binding modules, CBMs) wat spesifiek die selwandpolimere van die plant selwand herken, gebruik. Met hierdie metode het ons die vlakke van spesifieke polimere gemeet asook die skommeling in hulle vlakke soos dit beïnvloed is deur eksterne faktore soos ensiem hidroliese. Die CoMPP metode is tesame met monosakkaried profiel analise, met behulp van GC-MS, wat die boublokke van die selwand polimere bepaal, asook infrarooi spektroskopie om die veranderinge in die oorhoofse chemiese profiel te bepaal, gebruik. Datastelle wat met die selwand karakteriserings tegnieke gegenereer is, is ontleed met een- en multiveranderlike statistiese metodes om die hoof tendense in die data op te spoor. Hierdie studie het die selwand verskille, op die polimeervlak, van Pinotage druiwe uitgelig. Verskillende rypheidsgrade asook hoe dit verander tydens ‘n standaard wynfermentasie is gevolg. Laasgenoemde het die vrystelling van homogalakturonaan en die ontbloting van arabinogalaktoproteïene tot gevolg gehad. Met die byvoeging van maserasie ensieme was dit duidelik dat addisionele pektienverwydering plaasgevind het en dat die ensieme die selwand van die ryp druiwe ontrafel het. In oorryp druiwe was daar geen addisionele selwand afbreking sigbaar as gevolg van die aksie van maserasie ensieme nie, wat moontlik aandui dat die inherente druif ensieme reeds uitgebreide selwand afbraak versoorsaak het. Wanneer gesuiwerde ensieme met geïsoleerde selwande van Pinotage druiwedoppe en met Chardonnay druiweprosesserings afval geïnkubeer is onder gebufferde kondisies, is verskillende vlakke van ensiematiese hidroliese waargeneem en geklassifiseer. Die volgorde waarin die selwand polimere geëkstraheer is, asook die invloed van spesifieke ensieme in die bevordering van die ekstraksie proses, het belangrike inligting verskaf oor die toeganglikheid van spesifieke selwand polimere. Sinergistiese aksie tussen, byvoorbeeld ‘n endo-poligalakturonase (EPG) en ‘n endo-glukanase (EG) is geidentifiseer met behulp van die CoMPP data. Hierdie EPG en EG sinergisme is ook geïllustreer met ‘n gisras (‘n Saccharomyces paradoxus x S. cerevisiae hibried) wat in ‘n gebufferde druifprosesserings afval suspensie gefermenteer het. Hierdie gisras het ‘n endogene EPG en is ontwerp om ook ‘n rekombinante EG uit te druk vanaf ‘n genoom geïntegreerde kasset. Die selwande van die druiweprosesserings afval wat na die fermentasie geïsoleer is, was ontrafel en pektienverwydering het plaasgevind, soos bevestig met CoMPP data. In hierdie studie is bewys dat die selwand karakteriserings tegnieke vinnig en sensitief is. Dit het insigte verskaf oor die struktuur van die druifselwand en is gebruik om die veranderinge as gevolg van rypheidsverskille, wynfermentasie, ensiem hidroliese en hitte prosessering te evalueer. Buiten die bydraes tot kennis oor hierdie onderwerpe, is die bruikbaarheid van hierdie tegnieke ook aangetoon, veral in die evaluasie van verskillende ensieme en ensiemkombinasies, asook mikroörganismes vir die afbraak van druifweefsel.

<p>The traditional standing in the practice of negotiation which is main concerned with the substance of the proposal for a solution has been somewhat altered by Zartman who do acknowledge the importance of the first idea but adds the dimension of the timing of the efforts for a resolution. Throughout the schools of crisis management and conflict resolution this concept has made its name as the ‘ripeness theory’. The focal point of the theory is termed as the ‘Mutually Hurting Stalemate’ (MHS), a situation where the conflicting parties sense their positions in a hurting impasse.</p><p>The concept of a ripe moment does not only centre on the parties’ perception of a MHS but is optimally associated with an impending, past or recently avoided catastrophe. Even though the catastrophe is not necessary to either the definition or the existence of a MHS it provides a deadline or a lesson that pain can be sharply increased in something is not done about it now. This in linked with the idea behind the concept that, when the parties find themselves locked into a conflict from which they cannot escalate to victory and this deadlock is painful to them (although not necessarily in equal degrees or for the same reasons), they seek a way out.</p><p>A unique opportunity presented itself when a earthquake struck the areas between India and Pakistan the 8th of October 2005. Did the post-quake scenario present a new opportunity to collaborate on immediate relief activity and long-term build up? Could suspicion be buried with the wreckage? Could the disaster be a push to intensify the peace process?</p><p>The aim of this study is to find out if the disaster has made the conflict ripe for resolution or more advanced mediation. The empirical chapters is going down two avenues including the political elites (and their actions) as well as the internal political process which in this study is made up by a) the militancy, and b) editorials from major Pakistani and Indian newspapers.</p><p>The results of the study can be summed with that the earthquake has not made the conflict ripe for resolution (as in final resolution) but definitely made it ripe for more advanced mediation. This is based on the numerous important counter building measures carried out by the elites of India and Pakistan and the fact that the Kashmiri people were involved in the process. As for the internal political process the militancy did not show any will of collaborate or changing position in the conflict. The results of the newspaper’s editorials is not entirely positive either although both Pakistan and Indian newspapers had a rather positive outlook towards the increased Indo-Pak cooperation and the prospects for the future.</p>

This thesis looks at the conflict transformation processes, which took place in the Syrian conflicts with Turkey and Israel during the 1990s. The aim is to understand the reasons behind the different outcomes of these conflict transformation processes of Syria with Turkey and Israel. This thesis argues that the high-level of ripeness conditions in the Syrian-Turkish conflict, compared to the conditions in the Syrian-Israeli conflict, was the determinant of effectiveness, that is, for the signing of an agreement that symbolized the transformation in relations. More theoretically, the interaction between objective and subjective conditions of ripeness is more evident in the Syrian-Turkish case than in the Syrian-Israeli conflict, and this is the explanatory factor for the differing outcomes in these transformation processes.

The main aim of this work was to evaluate the phenolic compounds of Merlot grapes and wines, from vineyards located at Dom Pedrito (Campanha Gaúcha) and Bento Gonçalves (Serra Gaúcha). The following aspects were evalueted: fenolic and industrial ripeness; correlation between the grapes phenolic potencial and the wine phenolics; changes in phenolic compounds during the aging of the wines; impacto of maceration time of wine phenolic composition. The study was conducted for three years: 2009, 2010 and 2011. After grape ripeness evaluations, grape samples were harvested, crushed and fermented , with three different maceration techniques. The phenolic composition of the wines were analyzed after bottling and during aging. The vineyard localization have a great influence on Merlot wine phenolic composition; the grape characteristics was most important than maceration techniques to the wine composition. Important differences, among this two regions, have been found in the content and in the composition of phenolic compounds in the grapes and wines. Dom Pedrito grapes achieved a good cellular maturity, however, when compared with Bento Gonçalves grapes, the anthocyanin content is lower and the quantity of seeds tannins are higher than 50%. The phenolic potential allowed to estimate the total phenolic content, color due polymeric anthocyanins and procyanidin content of Merlot wines. Extended maceration (15 days) are recommended to Dom Pedrito grapes, however it is observed an increase in the pH value; the total crushing of grapes or not will not influence this aspect. During the aging, the results are dependent of vineyard location; Dom Pedrito wines showed a greater polimerization velocity and the differences among maceration times decreased for all wines studied. The main differences among wines from this two regions were color intensity, anthocyanin content, color due polymeric anthocyanin and total phenolic conten of the wines. These facts allows to state that Merlot wines from Serra Gaúcha could be aging for a periodo greater than Campanha Gaúcha wines. / O objetivo principal deste trabalho foi realizar um estudo dos compostos fenólicos em uvas e vinhos da variedade tinta Vitis vinifera Merlot, cultivadas em vinhedos dos município de Dom Pedrito (região da Campanha Gaúcha) e de Bento Gonçalves (região da Serra Gaúcha). Para tanto os seguintes aspectos foram avaliados: maturação fenólica e industrial de uvas amostradas; correlação entre o potencial fenólico estimado nas uvas com a composição fenólica e a cor dos vinhos resultantes; mudanças nos teores de compostos fenólicos dos vinhos elaborados e efeito do tipo de maceração sobre os compostos fenólicos dos vinhos. O estudo foi realizado por três safras: 2009, 2010 e 2011. Após a análise da maturação fenólica e industrial, amostras destas uvas foram vinificadas em pequena escala, com diferentes técnicas de maceração. Os vinhos foram analisados após o engarrafamento e durante o envelhecimento em relação ao conteúdo de compostos fenólicos. As uvas e os vinhos da variedade tinta Merlot apresentaram diferenças de acordo com a localização do vinhedos, sendo que as características das uvas foram mais importantes para o vinho resultante do que as técnicas de vinificação empregadas. Foram encontradas diferenças importantes no conteúdo e no comportamento dos compostos fenólicos entre as duas regiões representadas nesse estudo, tanto em relação a uva quanto ao vinho. As uvas cultivadas nos vinhedos do município de Dom Pedrito atingem uma maturação celular adequada, no entanto, o teor de antocianinas é menor e o teor de taninos nas sementes é superior a 50%, comportamento oposto as uvas cultivadas no município de Bento Gonçalves. A análise do potencial fenólico das uvas permite estimar o conteúdo de polifenóis totais, a porcentagem da cor devido a antocianinas poliméricas e a quantidade de procianidinas presentes no vinho a ser elaborado com uvas dessa variedade. Em relação a técnica de vinificação para a região de Dom Pedrito, recomenda-se o uso de maceração extendida (15 dias no minímo), porém há uma tendência de elevação do valor de pH do vinho resultante; o esmagamento total ou não da uva não irá influenciar esse aspecto. Durante o envelhecimento, os vinhos apresentaram resultados de acordo com a região de origem da uva, sendo que os vinhos de Dom Pedrito apresentam uma maior velocidade de polimerização; as diferenças entre os tempos de maceração diminuem com o envelhecimento do vinho para todos os vinhos analisados nesse estudo. As principais diferenças entre os vinhos dos dois municípios estudados deve-se a intensidade de cor, ao conteúdo de antocianinas, a porcentagem de cor devido a antocianinas poliméricas e ao teor de polifenóis totais nos vinhos. Estes fatos permitem afirmar, em parte, que os vinhos Merlot da Serra Gaúcha podem ser envelhecidos por mais tempo e que os vinhos Merlot oriundos da Campanha Gaúcha podem e devem ser consumidos mais jovens.

Sangin District, in Helmand Province, was once described by US Defense Secretary Robert Gates as “the most dangerous not only in Afghanistan but maybe the whole world.” Nevertheless, Afghan Government officials received a written offer of peace from the principal local grouping aligned to the Taliban on the 29th May 2010, before NATO’s surge, or Sangin’s handover from U.K. to U.S. forces. This offer evolved into the local negotiated agreement known as the Sangin Accord, announced in January 2011. This is the first academic study of that agreement. This work also considers relationships between motivations for negotiation at the local level, and international policy and actions: military power, stabilisation activities, and reconciliation (including the co-option and legitimation of enemies). It compares explanations for negotiated agreements from academic theory and military doctrine, especially I. William Zartman’s ripeness theory and its evolutions, and offers suggestions for other local reintegration or reconciliation scenarios. The conclusions offer observations on applying Ripeness theory when intervening to seek political reconciliation in a local area removed from centralised authority, and without a permanent military advantage – which I term ‘fringe areas’. It highlights the impact of history (both received and remembered), and traumatic experiences, on memory, perception and rationality; vital factors for Ripeness theory. Finally, it explores the paradox between policymakers’ desire to negotiate from a position of strength, and Ripeness theory’s contradictory requirement for a mutually perceived hurting stalemate – simultaneously alongside a political Way Out – as essential preconditions to genuine negotiation.

How does the killing or capture of rebel leaders affect the ends of conflict? Although decapitation scholars argue that it reduces the duration of conflict by disrupting rebel group organizational capacity, few have ever researched what effects decapitations could have on peace negotiations. After reviewing the literature within the field of decapitation and the ripeness theory of negotiation this paper tests the hypothesis that Successful decapitations are likely to increase the duration of time it takes for the government to agree on seeking a negotiated end to their conflict. This small n-study uses Mill´s method of disagreement to compare the civil wars in Colombia and El Salvador where decapitations did and did not take place respectively. Although a weak correlation exists the casual mechanism did not find support and therefor the hypothesis was rejected. There was however a relation between the presence of decapitation and government perception of stalemate that could affect how a conflict reaches the point of ripeness.

The negative effects of the Russian invasion of Ukraine in 2022 has been felt on a global scale.This makes it more relevant than it has been in a long time to understand how to achievesuccessful mediation and negotiation between Russia and post-soviet states. By examining theRusso-Georgian War of 2008 and the Russo-Ukrainian War that began in 2022, and thencomparing the two cases. This paper aims to investigate what factors contribute to successfulmediation in these two cases, and to hypothesise what obstacles exist for achieving successfulmediation in the war between Russia and Ukraine. The method used for this purpose isprocess-tracing, and the theoretical framework that has been used is Zartmans ripeness theoryand its formula for the concepts of mutually enticing opportunity, mutually hurting stalemate,ripe moment, and way out. The results of this study shows that a ripe moment existed in theconflict between Russia and Georgia despite the weak grounds for the existence of a mutuallyhurting stalemate. The study also concluded that the ceasefire agreement between the twocountries included a strong presence of one of the subcategories of the mutually enticingopportunity concept. Furthermore, the study also showed that a mutually hurting stalemate doesnot exist in the war between Russia and Ukraine, but simultaneously indicated strong grounds fora mutually hurting stalemate developing in the near future. Finally, the study identified fourdifferent obstacles for successful mediation between Russia and Ukraine. These related to theexistence of a mutually hurting stalemate, the motivations of the two conflict parties, and thechallenge of developing a mutually enticing opportunity.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

L'UMR ITAP d'IRSTEA à Montpellier et la société Pellenc SA souhaitent développer un système de mesure par spectrométrie visible - proche infrarouge permettant d'évaluer la qualité des olives et d'en suivre la maturité. La mesure doit être effectuée sur une seule olive et de manière non destructive. Les critères de maturité retenus pour une première phase d'étude sont les teneurs en eau et en huile. L'objectif de ces travaux est d'optimiser la mesure des critères de maturité par spectrométrie portable, en s'adaptant aux contraintes induites par l'objet d'étude et en levant des verrous imposés par la technologie retenue. En lien avec les objectifs industriels, trois questions scientifiques ont été soulevées :QS1 : Comment obtenir les valeurs de référence des critères de maturité à partir d'une seule olive ?QS2 : Comment mesurer le spectre d'une olive ? Quelle configuration optique est la plus adaptée à l'objet mesuré ? Quel volume de l'olive est interrogé lors de la mesure spectrale ? Le noyau intervient-il dans cette mesure ?QS3 : Comment étalonner la mesure spectrale ? Les modèles de prédiction sont-ils robustes au regard d'une variété non incluse dans leur étalonnage ? Comment inclure la masse du noyau dans les valeurs prédites ?Afin de répondre à ces questions, des études expérimentales et comparatives ont été menées. Pour la détermination de la teneur en huile (QS1) deux méthodes ont été évaluée, la résonance magnétique nucléaire (RMN) et l'extraction à l'hexane, lorsqu'elles sont appliquées à la pulpe d'une olive unique. L'étude sur les différentes configurations optiques (QS2) a permis de mettre en évidence l'impact de chacune sur la mesure spectrale et ainsi déterminer si l'ensemble de ces configurations proposées (transmission, réflexion diffuse avec propagation guidée de la lumière au moyen d'une sphère, réflexion diffuse avec propagation libre de la lumière et rétrodiffusion) sont envisageables pour la mesure sur une seule olive. De plus, ces travaux se sont intéressés au volume de peau et de pulpe réellement interrogé lors de la mesure spectrale par une étude de la perte de lumière transmise à travers la peau et la pulpe. Le questionnement de l'étalonnage des mesures spectrales (QS3) a consisté en une analyse fine des modèles construits mais aussi en une étude de la robustesse et des différentes méthodes envisageables pour l'améliorer (sélection de longueurs d'onde, mise à jour des modèles, correction “biais-pente”, méthode DOP). Le dernier point traité par ces travaux de thèse est la prise en compte de la masse du noyau dans les valeurs prédites et l'évaluation des différentes méthodes pour réaliser cette correction.L'ensemble des résultats obtenus au cours de cette thèse ont servi à fournir des éléments pour guider la conception d'un outil portable de mesures par spectrométrie sur olives individuelles. / ITAP Research Unit of IRSTEA and Pellenc SA company want to developa visible - near infrared spectroscopy measurement system in order to assess the quality of olives and monitor their ripeness. The measurement has to be non-destructive and performed on a single olive. The ripeness criteria selected are water and oil content. The main objective of this work is to optimize the measurement of these criteria, recorded by a portable spectrometer, by taking into account the constraints linked to the studied object and by overcoming the obstacles imposed by the technology used. In relation to the industrial objectives, three scientific questions were raised :SQ1 : How to get the reference values of the ripeness criteria from a single olive ?SQ2 : How to measure the spectrum of one olive ? Which optical configuration isbest suited for an olive ? Which volume of the olive is actually analyzed during thespectral measurement ? Does the spectrum contain information about the kernel ?SQ3 : How to calibrate the spectral measurement ? Are the prediction models robustregarding a variety not used for the calibration step ? How to include the kernel mass in the predicted values ?In order to answer those questions, experimental and comparative studies have been led. As the determination of water content is easily transposable to a single olive, only the measurement of oil content is studied (SQ1). Two existing methods nuclear magnetic resonance and hexane extraction have been characterized end evaluated when they are applied to the pulp of a single olive.The comparative study conducted on different optical configurations(SQ2) has high-lighted the impact of each configuration (transmission, diffuse reflectance with guidedpropagation of light through a sphere, diffuse reflectance with free propagation of light and interactance) on the spectral measurement. This study has also determined if all of these configurations are suitable for the whole olive measurements. Furthermore, the real volume analyzed during the spectral measurement has been investigated by studying the loss of transmitted light through the skin and the pulp.In order to answer SQ3, the present work provides optimized models for prediction ofwater content on the one hand and oil content on the other hand. The robustness study leads us to consider different methods (Model Update, Biais and Slope, DOP, wavelength selection) depending on the correction set used and therefore the finality of the future device. Concerning the introduction of kernel mass in predicted values, it has be done using various methods which are more or less destructive. The choice of one of these methods has been be determined by the technical possibilities of the device and the minimum expected accuracy of water and oil content predictions.Therefore, the results of this thesis provide some elements to guide the development of a portable spectrometer for measurements on individual olive fruits.