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Aims:  To assess suitability of Multi Locus Sequence Typing (MLST) for investigating the biodiversity of wine yeast strains. This method was compared with established ones like microsatellite analysis or amplification of genomic regions flanked by repeated (delta) elements. Methods and Results:  DNA fragments were amplified and sequenced for 26 loci representing housekeeping genes, open reading frames (ORFs) of unknown functions or intergenic regions. A set of seven loci was tested on 84 Saccharomyces cerevisiae strains, including 65 strains isolated from traditional wineries in Lebanon, commercial wine strains and Asian isolates. An overall sequence diversity of 2·05% was observed, consisting of single nucleotide polymorphisms, 60% of them occurring in a heterozygous state. The number of polymorphic sites per locus varied between 4 and 14. The same set of strains was analysed by microsatellite typing on six polymorphic loci and by interdelta amplification. Conclusions:  Clustering of MLST profiles clearly differentiated the Asian group of strains from Lebanese and European commercial strains that appear closely related. The current MLST scheme appears less discriminatory (92·27%) on closely related wine yeasts than microsatellite or interdelta typing (>99%). Significance and Impact of the Study:  MLST is a highly reliable method for relatedness inference and promising for wine yeast typing.

The aim of the present study was to quantify some nutritional and safety quality parameter changes that take place in nuts (roasting) and sesame seeds (dehulling, roasting, milling, and sterilization) during processing. Such evaluation was based on chemical analysis of various indicators of lipid alteration in raw and processed pistachios, almonds, peanuts, and tahina. Lipid oxidation was assessed by the evolution of lipid oxidation products including hydroperoxides, p-anisidine, and thiobarbituric acid reactive substances, as well as carboxymethyllysine (CML) and trans fatty acids (tFAs). All these parameters were significantly affected by the different processing stages, especially by roasting and sterilization (tahina). Nut roasting and sesame heat treatment increased the primary (hydroperoxides) and secondary (aldehydic compounds) lipid oxidation products, with the p-anisidine value reaching 6-11.5 and thiobarbituric acid reactive substances 3-5 mg/kg (equiv of malondialdehyde) in the different end products. In addition, roasting led to the formation of CML (between 12.7 and 17.7 ng/mg) and tFAs (between 0.6 and 0.9 g/100 g) in nuts and tahina, which were absent in the raw material. Roasting parameters appear as the critical factor to control to limit the CML and tFA formation in the final product.

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Effect of calcium and sodium ions on coffee proteins and foam.The brew is prepared by decoction in a graduated cylinder with demineralized water containing CaCl 2 or NaCl (between 0 and ~0.1 M) and 10 % (w/v) of ground coffee. Ca ++ decreases the solubility of proteins (PR) of coffee and its foaming power (PM) but increases foam stability (SM), probably by gel formation. Addition of Ca ++ is also accompanied by a decrease of pH. Na + has no significant effect (p > 0.05) on PR, PM, SM or pH. The measurement of electrical conductance shows that the two ions are partially immobilized by one and/or the other component of the brew.

A total of 296 isolates of Saccharomyces cerevisiae sampled from naturally fermenting grape musts from various locations in Lebanon were typed by interdelta fingerprinting. Of these, 88 isolates were compared with oenological strains originating from various countries, using microsatellite characterization at six polymorphic loci. These approaches evidenced a large diversity of the natural oenological Lebanese flora over the territory as well as in individual spontaneous fermentations. Several cases of dominance and perenniality of isolates were observed in the same wineries, where fermentations appeared to involve lineages of sibling isolates. Our work thus evidenced a “winery effect” on strains’ relatedness. Similarly, related or identical strains were also detected in vicinal wineries, suggesting strain circulation within small geographical areas and a further “vicinity effect”. Moreover, and despite its diversity, the Lebanese flora seemed interrelated, on the basis of microsatellite loci analysis, in comparison to worldwide communities. We finally tested the ability of 21 indigenous strains to act as potential starters for winemaking. Seven of them passed our pre-selection scheme and two of them at least may be good candidates for use provided pilot-scale assays confirm their suitability.

<p style="text-align: justify;">The effect of different concentrations (0-20 LMR) of six pesticides on the aerobic growth of two yeast strains (<em>Saccharomyces cerevisiae, Metschnikowia pulcherrima</em>) was analysed. The penconazole was shown as the most efficient and its effect was then studied under fermentative conditions. <em>Saccharomyces cerevisiae</em> appeared very sensitive under aerobiosis while the fermentative cultures seemed poorly affected. On the opposite, <em>Metschnikowia pulcherrima</em> was poorly affected under aerobiosis but was severely affected under fermentative conditions. The yields as well as the reaction rates decreased when initial concentrations of penconazole were increased. At least, it was shown that both strains were able to adsorb a certain ratio of the pesticide; but the pesticide was not degraded. Also for an initial value greater than 2 LMR, the residual quantity of the pesticide was above the admitted level.</p>