PHYSICO-CHEMICAL AND MICROBIOLOGICAL CHARACTERIZATION OF NATURAL FERMENTING OLIVE BRINES

The main objective of this work is to study the characterization of physico-chemical and microbiological of fermenting green olive brines at different times of fermentation. The technological and probiotic properties of lactic acid bacteria strains isolated from brines were also characterized, 24 brine samples were sampled from Triffa conserves entreprise, an industrial zone of Oujda city in eastern Morocco, during 2014-2015 and 2015-2016 campaigns, 240 isolates of lactic acid bacteria have been isolated, and they have undergone a series of tests to finally select the so-called probiotic bacteria. 41 strains were resistant to low pH (3, 2.5, 2), bile salts (0.3 and 1%, w/v) and 7 strains among the 41 were resistant to saline stress (8%, w/v) and endowed with acidification capacity and have a good enzymatic activity and a broad spectrum of antibacterial activity against pathogenic and non-pathogenic bacteria such as (Escherichia coli, Staphylococcus aureus, Listeria innocua, Pseudomonas aeruginosa and Micrococcus luteus). These results show the ability of these strains to dominate and grow in the digestive tract.These potential probiotic strains will be used as concentrated ferments in the fermentation and bioconservation of foods

Ballistic and Diffuse Electron Transport in Nanocontacts of Magnetics

The transition from the ballistic electron transport to the diffuse one is experimentally observed in the study of the magnetic phase transition in Ni nanocontacts with different sizes. It is shown that the voltage $U_C$ needed for Joule heating of the near-contact region to the critical temperature does not depend on the contact size only in the diffuse mode. For the ballistic contact it increases with decrease in the nanocontact size. The reduction of the transport electron mean free path due to heating of NCs may result in change of the electron transport mode from ballistic to diffusive one.Comment: 7 pages, 2 figures accepted for the publication in JETPL (http://www.jetpletters.ac.ru). Will be published on 25 april 201

Microstructural evolution in solution heat treatment of gas- atomised Al alloy (7075) powder for cold spray

Cold gas dynamic spray is being explored as a repair technique for high-value metallic components, given its potential to produce pore and oxide-free deposits of between several micrometers and several millimeters thick with good levels of adhesion and mechanical strength. However, feedstock powders for cold spray experience rapid solidification if manufactured by gas atomization and hence can exhibit non-equilibrium microstructures and localized segregation of alloying elements. Here, we used sealed quartz tube solution heat treatment of a precipitation hardenable 7075 aluminum alloy feedstock to yield a consistent and homogeneous powder phase composition and microstructure prior to cold spraying, aiming for a more controllable heat treatment response of the cold spray deposits. It was shown that the dendritic microstructure and solute segregation in the gas-atomized powders were altered, such that the heat-treated powder exhibits a homogeneous distribution of solute atoms. Micro-indentation testing revealed that the heat-treated powder exhibited a mean hardness decrease of nearly 25% compared to the as received powder. Deformation of the powder particles was enhanced by heat treatment, resulting in an improved coating with higher thickness (* 300 lm compared to * 40 um for untreated feedstock). Improved particle–substrate bonding was evidenced by formation of jets at the particle boundaries

Statistics of Heat Transfer in Mesoscopic Circuits

A method to calculate the statistics of energy exchange between quantum systems is presented. The generating function of this statistics is expressed through a Keldysh path integral. The method is first applied to the problem of heat dissipation from a biased mesoscopic conductor into the adjacent reservoirs. We then consider energy dissipation in an electrical circuit around a mesoscopic conductor. We derive the conditions under which measurements of the fluctuations of heat dissipation can be used to investigate higher order cumulants of the charge counting statistics of a mesoscopic conductor.Comment: 9 pages, 6 figure

Fermentación controlada de aceitunas verdes picholine marroquíes sometidas a choque térmico e inoculadas sin sal

The present work reports the controlled fermentation of heat-shocked, unsalted and inoculated green olives. The effects of heat-shock (60, 70 and 80 °C three times for 5 min), inoculation with the oleuropeinolytic strain of L. plantarum FSO175 (L.p-FSO175) and the addition of Cell-Free Supernatant of C. pelliculosa L18 (CFS of C.p-L18) on the fermentation process of unsalted green olives were examined. The results showed a drastic reduction in the initial indigenous Enterobacteria, and an improvement in the acidification of heat-shocked olives at 70 and 80 °C, when compared to 60 °C. The inoculation with L.p-FSO175 and addition of CFS of C.p-L18 enhanced the fermentation and preservation of unsalted green olives, indicated by a significant decrease in pH, increase in free acidity and total disappearance of Enterobacteria. The heat-shock treatment at high temperature (80 °C), inoculation with L.p-FSO175 and addition of CFS of C.p-L18 led to the best reduction in bitterness, and favorable color changes (L, a, and b) in fermented olives. This sequential method led to more appreciated sensory characteristics (mainly bitterness and color) of fermented olives, lower spoilage incidence in olives, and reduced fermentation time to 50 days, and therefore may be suitable to control the fermentation of unsalted green olives of the Moroccan picholine variety.El presente trabajo reporta la fermentación controlada de aceitunas verdes sometidas a choque térmico, sin salar e inoculadas. Se estudian los efectos del choque térmico (60 °C, 70 °C y 80 °C tres veces durante 5 min), la inoculación con cepa oleuropeinolítica de L. plantarum FSO175 (L.p-FSO175) y la adición de sobrenadante libre de células de C. pelliculosa L18 (CFS de C.p-L18), sobre el proceso de fermentación de aceitunas verdes sin salar. Los resultados mostraron la drástica reducción de las enterobacterias autóctonas iniciales, y la mejora de la acidificación de las aceitunas sometidas a choque térmico de 70 °C y 80 °C, en comparación con 60 °C. La inoculación con L.p-FSO175 y la adición de CFS de C.p-L18 mejoró la fermentación y conservación de las aceitunas verdes sin salar, indicada por una disminución significativa del pH, aumento de la acidez libre y desaparición total de enterobacterias. El choque térmico a alta temperatura (80 °C), la inoculación con L.p-FSO175 y la adición de CFS de C.p-L18 condujeron a una mejor reducción del amargor y cambios de color favorables (L, a y b) en aceitunas fermentadas. Este método secuencial, que permitió apreciar las características sensoriales (principalmente amargor y color) de las aceitunas fermentadas, y una menor incidencia de deterioro en las aceitunas, y redujo el tiempo de fermentación a 50 días, puede ser adecuado para controlar la fermentación de aceitunas verdes sin salar de Marruecos, variedad picholine

Fermentación controlada de aceitunas verdes picholine marroquí mediante cepas de lactobacilos degradantes de oleuropeína

The control of the spontaneous fermentation process of un-debittered Moroccan Picholine green olives was undertaken basing the inoculation with two lactobacilli strains (Lactobacillus plantarum S175 and Lactobacillus pentosus S100). These strains, previously selected in our laboratory for their oleuropein-degrading capacity, were inoculated in olives brined at 5% of NaCl, and then incubated at 30 ÅãC. The physico-chemical parameters (pH, free acidity, reducing sugars, sodium chloride, oleuropein and its hydrolysis products), and the microbiological parameters (mesophilic aerobic bacteria, coliforms, Staphylococcus, lactic acid bacteria and yeasts and moulds), were regularly analyzed during the fermentation time. The results obtained showed the effectiveness of the lactic acid bacteria strains to develop suitable oleuropein biodegradation and controlled lactic fermentation processes more than the un-inoculated olives (control). This result was confirmed by the rapid elimination of coliforms and staphylococcus, the accumulation of hydroxytyrosol as a result of oleuropein biodegradation, and a drastic reduction in spoiled olives with good quality fermented olives.Se llevó a cabo el control del proceso de fermentación espontánea de aceitunas verdes sin desamargar picholine marroquí basado en la inoculación con dos cepas de lactobacilos (Lactobacillus plantarum S175 y Lactobacillus pentosus S100). Estas cepas, seleccionadas previamente en nuestro laboratorio por su capacidad de degradar a la oleuropeína, se inocularon en las aceitunas en salmuera al 5 % de NaCl, y después se incubaron a 30 °C. Los parámetros físico-químicos (pH, acidez libre, reducción de azúcares, cloruro sódico, oleuropeína y sus productos de hidrólisis) y los parámetros microbiológicos (bacterias aerobias mesófilas, coliformes, estafilococos, bacterias lácticas y levaduras y mohos), fueron analizados regularmente durante el tiempo de fermentación. Los resultados obtenidos mostraron la eficacia de las cepas de bacterias lácticas para desarrollar una adecuada biodegradación de la oleuropeina y los procesos de fermentación láctica controlados más que en el caso de las aceitunas no inoculadas (control). Estos resultados fueron confirmados por la rápida eliminación de coliformes y estafilococos, por la acumulación de hidroxitirosol como resultado de biodegradación de la oleuropeína, y por ladrástica reducción de aceitunas estropeadas y por la buena calidad de las aceitunas fermentadas

Heat treatment of cold-sprayed C355 Al for repair: microstructure and mechanical properties

Cold gas dynamic spraying of commercially pure aluminum is widely used for dimensional repair in the aerospace sector as it is capable of producing oxide-free deposits of hundreds of micrometer thickness with strong bonding to the substrate, based on adhesive pull-off tests, and often with enhanced hardness compared to the powder prior to spraying. There is significant interest in extending this application to structural, load-bearing repairs. Particularly, in the case of high-strength aluminum alloys, cold spray deposits can exhibit high levels of porosity and microcracks, leading to mechanical properties that are inadequate for most load-bearing applications. Here, heat treatment was investigated as a potential means of improving the properties of cold-sprayed coatings from Al alloy C355. Coatings produced with process conditions of 500 °C and 60 bar were heat-treated at 175, 200, 225, 250 °C for 4 h in air, and the evolution of the microstructure and microhardness was analyzed. Heat treatment at 225 and 250 °C revealed a decreased porosity (~ 0.14% and 0.02%, respectively) with the former yielding slightly reduced hardness (105 versus 130 HV0.05 as-sprayed). Compressive residual stress levels were approximately halved at all depths into the coating after heat treatment, and tensile testing showed an improvement in ductility

Etude comparative des huiles essentielles de six variétés des nouvelles obtentions d’agrumes cultivées au Maroc

In this research, the essential oils of six INRA’s citrus varieties, which are mandarines El Marzaka, El Mahdia, El Gharabaouia, El Hamra, El Maamoura and orange Shemsia were compared and analyzed. For this purpose, the oil yield, chemical composition, antioxidant and antimicrobial activity were investigated. The extraction was carried out by hydro-distillation. The highest essential oil yield was obtained for Shemsia (5,63%/ DW). The main components of essential oils were identified by GC-MS and their antioxidant activity was determined by DPPH method. The major component of essential oils is D-Limonene, and the highest antioxidant activity was obtained for Shemsia essential oil (24.02%). Antifungal activity was detected in all varieties and the highest value was identified in El Maamoura, while antibacterial activity was not distinguished. From the obtained results, we note that the essential oils of El Maamoura can be valued as a fungicide in agriculture or in medical field. in addition, El Hamra, can be used in Solar cream industry.Les huiles essentielles de six variétés d’agrumes obtenues de l’INRA du Maroc, et qui sont : les mandarines El Marzaka, El Mahdia, El Gharabaouia, El Hamra, El Maamoura et l’orange Shemsia ont été comparées et analysées. La comparaison a été effectuée en termes de rendement, de composition chimique, d’activité antioxydante et d’activité antimicrobienne de ces huiles essentielles. L’extraction a été effectuée par hydro-distillation. Le rendement en huile essentielle le plus élevé a été obtenu chez la variété Shemsia (5,63%/PS). Les principaux composants des huiles essentielles ont été identifiés par CPG-MS et leur activité antioxydante a été déterminée en testant la capacité de piégeage des radicaux libres par DPPH. Le composant majeur des huiles essentielles est le D-Limonène et la plus haute activité antioxydante a été obtenue pour l'huile essentielle d’El Maamoura (24,02%). L'activité antifongique a été détectée chez toutes les variétés et la valeur la plus élevée a été repérée chez El Maamoura, alors que l'activité antibactérienne n'a été détectée chez aucune variété. À partir des résultats obtenus, nous constatons que l’huile essentielle de la mandarine El Maamoura peut être valorisée sous forme de fongicide dans le domaine d’agriculture ou dans le domaine médical. En plus, la variété El Hamra peut être incorporée dans l’industrie de la fabrication des crèmes solaires