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Monitoring and evaluating fermentative performance of sourdough used in bakery products typically involves discontinuous, destructive and costly analyses, resulting in substantial data that is expensive to exploit using conventional methods. The performance of sourdough is determined by its capacity to efficiently leaven the dough in the briefest timeframe possible, while simultaneously reducing the pH to an optimal level. This pH reduction facilitates the activity of enzymes, notably phytases, which break down phytates. Additionally, sourdough has the ability to generate ethanol, a crucial element contributing to the flavor and shelf life of the bread. A new, low-cost, non-destructive device has been developed with a system for real-time data acquisition, monitoring, visualization, as well as data processing, consolidation, and storage, thus simplifying the study of sourdough performance. Multiple specific sensors were integrated into an Arduino Uno board and placed in a connected fermentation chamber controlled by computer-installed software. The developed device enables real-time monitoring of critical parameters during sourdough fermentation. These include dough rising DRC (cm), gas release (CO2, ethanol) (ppmv or ml), pH, conductivity (uS/cm), moisture (%) and dough mass loss (g). Additionally, it measures temperature (°C), air humidity (%) and pressure (mbar) within the fermentation chamber. The device generates graphs, facilitating visual comparisons of sourdough fermentative performance. This graphical representation makes it easy to determine the end of fermentation. The developed application facilitated the management and utilization of the sourdough database. The device enables researchers to save time, reagents and equipment that are usually dedicated to such analyses. It achieves this by offering continuous and simultaneous monitoring of various sourdough fermentation parameters, allowing for an assessment of their fermenting capacity. Keywords: Sourdou

La stabilité des levains frais de panification, dans le temps, constitue une préoccupation majeure pour les professionnels. Trois principaux paramètres biochimiques (pH, ATT et conductivité) de cinq levains frais traditionnels de compositions différentes ont été surveillés pendant deux mois lors des rafraichissements. Le suivi de ces paramètres a montré que les valeurs moyennes de l’Acidité Totale Titrable (ATT) évoluent autour de 0,16 à 0,28 ml/jour, alors que le pH est resté relativement stable pendant les vingt premiers jours et après un arrêt de quatre jours sans rafraichissements, on a enregistré une augmentation de l’ordre de 14 à 17%. Les valeurs moyennes de la conductivité de départ sont de 0,96 à 2,13 avec une augmentation assez prononcée de 60% pour le levain L19 et faible (13%) pour les autres levains. Des modèles statistiques permettant la prédiction de l’ATT en fonction du pH et de la conductivité ont été développés afin d’éviter les analyses habituelles fastidieuses de l’ATT et d’estimer en temps réel sa valeur. Afin de prédire l’ATT indépendamment de la composition du levain, une équation commune faisant intervenir les valeurs moyennes des cinq levains étudiés a été également obtenue (ATT = 9,18*pH + 17,2* Conductivité - 40,8; avec R2 = 87,9%).   Mots clés: levains, rafraichissement, panification, prédiction acidité, The stability of fresh breadmaking sourdoughs over time is a major concern for professionals. Three main biochemical parameters (pH, TTA and conductivity) of five traditional fresh sourdoughs of different compositions were monitored over a two-month period during refreshments. Monitoring of these parameters showed that average Total Titrable Acidity (TTA) values evolved in the range of 0.16 to 0.28 ml/day, while pH remained relatively stable during the first twenty days, and after a four-day break without refreshments, an increase in the range of 14 to 17% was recorded. Average starting conductivity values ranged from 0.96 to 2.13, with a fairly pronounced increase (60%) for sourdough L19 and a small one (13%) for the other sourdoughs. Statistical models for predicting TTA as a function of pH and conductivity have been developed to avoid the usual tedious analysis of TTA and to estimate its value in real time. In order to predict TTA independently of sourdough composition, a common equation involving the mean values of the five sourdoughs was also obtained (TTA = 9.18*pH + 17.2* Conductivity - 40.8; with R2 = 87.9%). Keywords: Sourdoughs, refreshing, bread-making, acidity prediction

Fermentation with liquid sourdoughs can make a real contribution to the creation of a wide variety of bakery products distinguished by their flavor, texture and health benefits. The aim of the present study was to evaluate the fermentation potential of four liquid sourdoughs prepared in the laboratory, by monitoring the main bread-making parameters in real time, using a device with sensors. The results showed that the average bread-making time varied from 640 to 852 min, with an average specific volume ranging from 2.40 to 3.98 cm3/g, a final Total Titrable Acidity (TTA) ranging from 3.92 to 7.31 ml 0.1N NaOH/10 g and a final pH ranging from 3.31 to 3.89, an average production of CO2 from 0.51 to 1.01 L/kg of dough, while the average production of ethanol released varied from 4.94 to 10.6 L/kg of dough. L9 liquid sourdough prepared with wholewheat showed the best dough fermentation performance. Individual and vertical panigrams were used for visual comparison between these sourdoughs, in order to select the one most suitable for bread-making. Keywords: sourdough, rheology, bread-making, fermentation, yeast, lactic acid bacteria, La fermentation aux levains liquides peut contribuer à la création d'une grande variété de produits de boulangerie qui se distinguent par leur saveur, leur texture et leurs bienfaits pour la santé. Le présent travail a pour objectif d’évaluer le potentiel fermentaire de quatre levains liquides préparés au laboratoire, en suivant en temps réel les principaux paramètres de panification, à l’aide d’un dispositif de plusieurs capteurs. Les résultats obtenus montrent que la durée moyenne de panification a varié de 640 à 852 min, avec un volume spécifique moyen allant de 2,40 à 3,98 cm3/g, une Acidité Totale Titrable (ATT) finale allant de 3,92 à 7,31 ml de NaOH 0,1N/10 g et un pH final allant de 3,31 à 3,89, une production moyenne de CO2 dégagé de 0,51 à 1,01 L/kg de pâte, tandis que la production moyenne de l’éthanol dégagé a varié de 4,94 à 10,6 L/kg de pâte. Le levain liquide L9 préparé à la farine complète de blé présente la meilleure performance fermentaire de la pâte. Les panigrammes individuels et verticaux ont été utilisés pour la comparaison visuelle entre ces levains afin d’en choisir celui qui parait le mieux adapté à la panification du pain. Mot clés: levain, rhéologie, panification, fermentation, levure, bactérie lactique

Olive is one of the most ancient and important fruit tree crops in Morocco. Olive trees are affected by at least 15 viruses belonging to eight genera. Most of these viruses were isolated from symptomless trees and/or reported in a very limited number of trees. In order to check for the presence of olive-infecting viruses in Morocco, a preliminary survey was conducted during March-April 2014 and a total of 105 samples (cv. Picholine marocaine) were randomly collected from 15 commercial orchards located in three important olive-growing regions: Béni Mellal, Marrakech and Meknès. Samples were tested by RT-PCR, using specific primers, to search for the presence of eight olive viruses: Olive latent virus 1 (OLV-1), Olive latent virus 2 (OLV-2), Strawberry latent ringspot virus (SLRSV), Cucumber mosaic virus (CMV), Arabis mosaic virus (ArMV), Cherry leaf roll virus (CLRV), Olive latent ringspot virus (OLRSV) and Olive leaf yellowing-associated virus (OLYaV). About one third (34.3%) of the trees were infected. In particular, the closterovirus OLYaV was the most widespread, as it was detected in 16.2% of the samples, followed by the necrovirus OLV-1 (8.6%), the oleavirus OLV-2 (3.8%), the cucumovirus CMV (2.8%), the sadwavirus SLRV (1.9%), and the nepovirus ArMV (0.9%). The fact that these infections are mostly latent and the increasing of national demand for propagation material of high sanitary standard call for the implementation of a cleanup using both heat therapy and in vitro propagation for the establishment of olive foundation blocks. Key-words: Olive trees, olive-infecting viruses, Morocco

The purpose of the present study is to isolate, identify and characterize new yeast species of industrial interest. A total of 54 strains were isolated and identified from agricultural raw products and from by-products of the food industry. Among these, four strains were selected, purified and tested for their ability to perform efficient fermentation on Bouslikhène date juice. After the sequencing of the 18S gene of the ribosomal DNA, the two strains YS-DN1 and YS-M isolated respectively from dates and molasses have been identified belonging to Saccharomyces cerevisiae species. In addition, the other two strains, YS-OMP and YS-G isolated from olives and grapes belonged to Kluyveromyces marxianus (78% homology) and Candida utilis (89% homology) species, respectively. In addition, YS-DN1 strain showed the highest performance in terms of ethanol production in comparison with two other industrial reference strains. YS-DN1 strain was the only one that was able to grow at a temperature ranged from 35 to 40°C in the presence of a high alcoholic concentration and aggressive osmotic pressure condition. Finally, production of the cellular biomass of YS-DN1 strain was improved by optimization of temperature, Brix and pH fixed respectively at 29.75°C, 15.7% and 4.15. These values allowed to obtain a maximum of cells of about 8.4x10 8 UFC/ml. It was concluded that this strain is well suited for fruit vinegar production at a large-scale. Keywords: Isolation, Yeasts, Fermentation, Vinegar, Optimization, Dates, Stressors, La présente étude a pour but d’isoler, d’identifier et de caractériser de nouvelles souches de levures d’intérêt industriel. Un total de 54 levures ont été isolées et identifiées à partir de produits agricoles brutes et de sous-produits de l’industrie agro-alimentaire. Parmi ces isolats, quatre souches ont été retenues, purifiées et testées pour leur performance de fermentation sur un jus de dattes de variété Bouslikhène. D’après le séquençage du gène 18S de l’ADN ribosomal, les deux souches YS-DN1 et YS-M isolées respectivement à partir des dattes et de la mélasse ont été identifiées appartenant à l’espèce Saccharomyces cerevisiae. Par ailleurs, les deux autres souches YS-OPM et YS-G isolées des olives et des raisins appartiennent respectivement aux espèces Kluyveromyces marxianus, avec 78 % d’homologie et Candida utilis à 89% d’homologie. D’autre part, la souche YS-DN1, s’est identifiée comme la plus performante dans la production d’éthanol en comparaison à deux autres souches industrielles de référence. La levure YS-DN1 était l’unique souche capable de croître à une température entre 35 et 40°C en présence d’un taux alcoolique élevé et une pression osmotique agressive. Finalement, la production de la biomasse cellulaire de la souche YS -DN1 a été améliorée par optimisation des facteurs température, Brix et pH fixés respectivement à 29.75°C, 15.7% et 4.15. Ces valeurs ont permis d’obtenir un maximum de cellules de l’ordre de 8.4x10 8 UFC/ml. Il a été conclu que cette souche pourrait bien s’adapter à des usages industriels pour la production du vinaigre de fruits à grande échelle. Mots clés: Isolement, levures, Fermentation, Vinaigre, Optimisation, Dattes, Stress