There are about 40 durum wheat varieties registered in Turkey. Around 10 varieties are being commonly cultivated. Amanos 97, &Ccedil / esit 1252, Ege 88, Firat 93, Fuatbey 2000, Burgos, Kiziltan 91, Sari&ccedil / anak 98, Svevo and Zenith durum wheat varieties were used in this study. Semolina and pasta have been produced in an industrial plant under constant process conditions from these varieties. In general, pasta quality is determined by three main factors, the raw materials, the production recipe and the production process. In this study, the production recipe and the production process were fixed and only durum wheat varieties were variable. So, the effects coming from the production recipe and the production process on pasta quality were eliminated. Physical, chemical and sensory properties of these pasta were determined and the effect of different durum wheat varieties on pasta quality has been investigated to give a clear idea to the Turkish pasta industry about the most commonly grown durum wheat varieties in Turkey, hoping that Turkish pasta in domestic and international Markets will continue to grow with the help of clear understanding about the quality characteristics of the durum wheat they are using. v The important criteria of acceptability of pasta products is its cooking quality and cooking quality of pasta products is of importance to consumers and also to wheat producers, breeders and manufacturers. The pasta samples produced from Svevo, Zenith and Firat 93 varieties got the higher scores than others in pasta cooking quality while those produced from Sari&ccedil / anak 98, &Ccedil / esit 1252, Kiziltan 91, and Fuatbey 2000 durum wheat were evaluated as relatively low. The main reasons of cooking quality differences can be interpreted as a result of the difference in protein quantity and quality of the varieties. The bright yellow color of pasta products, rather than cooking behavior taste, is reported to be one of the most important considerations in assessing durum wheat quality. In this study, the pasta samples produced from Svevo, Zenith and Burgos varieties got the higher scores than others in pasta color (yellowness) while that produced from Firat 93 had the lowest yellow color. The main reasons of yellow color differences can be interpreted as a result of the differences in carotenoid pigments, lipoxygenase and peroxidase enzymes contents of the varieties.

Ce travail est une étude préliminaire qui a pour objectif principal d'étudier l'impact des caractéristiques de surface des poudres céréalières sur leurs mécanismes d'agglomération dans le cas particulier de la fabrication de couscous. Cet objectif a été réalisé par une approche multi-échelle : particules, mécanismes, et procèdes. A l'échelle des particules, on a identifié deux caractéristiques relatives à la réactivité physique et chimique des particules (la morphologie et la composition chimique de surface). D'abord, une méthode d'analyse d'images pour décrire la morphologie des particules a été introduite. Ensuite, l'applicabilité de la spectroscopie par photoélectron rayon-X (XPS) pour mesurer la composition chimique de surface des poudres céréalières a été on a examinée. A l'échelle des mécanismes, on a décrit et modalisé une étape importante des mécanismes d'agglomération des poudres céréalières. A l'échelle de procèdes, du couscous a été fabriqué à l'échelle pilote et ses paramètres de qualité ont été estimées. La relation entre les échelles a été évaluée en étudiant l'impact des caractéristiques des particules et de taux d'hydratation sur les mécanismes d'agglomération, le rendement d'agglomération, et la qualité finale de couscous. / Our research work is a preliminary study to investigate the impact that the surface characteristics of wheat powder particles have on their agglomeration mechanisms in the particular case of couscous production process. The objective of this research work was achieved by considering a multi scale approach: particle, mechanism, and process scale. On particle scale, we identified two characterizing factors of particles related to their physical and chemical reactivity (particles shape and surface chemical composition). We first presented a method based on image analyzing system to describe particles shape of wheat powders and then examined the applicability of X-ray photoelectron spectroscopy to measure the surface chemical composition of wheat powders. On mechanism scale, we described and modeled one stage of the wet agglomeration mechanisms of wheat powders. On process scale, we produced couscous in pilot scale and evaluated its quality parameters. The relationship between the scales was evaluated by studying the impact of particles characteristics and hydration rate on agglomeration mechanisms, agglomeration yield, and couscous quality.