No abstract

The QuEChERS method was applied to the determination of pesticide residues in vine (Vitis vinifera) leaves by LC-MSMS. The method was validated in-house for 33 pesticides representing 17 different chemical groups, that are most commonly used in grape production. Recoveries for the pesticides tested ranged from 75 to 104%, and repeatability and reproducibility relative standard deviations (RSDr% and RSDRw%) were less than 20%. The method was applied to the analysis of pesticide residues in 17 market brands of vine leaves processed according to three different preservation methods and sampled from the Lebanese market. Dried vine leaves were more contaminated with pesticide residues than those preserved in brine or stuffed vine leaves. The systemic fungicides were the most frequently detected among all the phytosanitary compounds usually applied to grape production. Brine-preserved and stuffed vine leaves contained lower concentrations of the residues but still contained a cocktail of different pesticides.

A process for hemicelluloses fractionation and purification from wheat straw and bran has been investigated and technical considerations (yields, purity) have been coupled to environmental characterizations (water consumption, carbon dioxide emissions) in order to develop an environment-friendly process. Extraction by twin-screw extrusion gave a yield in arabinoxylans equal to 8.5% (weight of (arabinose + xylose) in the extract after fractionation/dry weight of the destarched bran). The extraction of 86 kg of straw and bran (with a ratio 6.2:1) with 5.8 kg of NaOH in pellet form resulted in the production of a complex extract containing 1.0 kg of arabinoxylan polymer, which required concentration and purification steps. Evaporation (EV) followed by ethanol precipitation (P) and freeze-drying (FD), gave a yield in hemicellulosic powder of 36.5% (dry weight of powder/dry weight of extract after liquid/solid separation) with a total sugar content equal to 48.4% but also used a large amount of ethanol. The other studied purification process was based on a combination of ultrafiltration (UF), anion exchange chromatography (CHR) and spray-drying (SD). It gave a yield in hemicellulosic powders of 24.6% and a total sugar content equal to 28.7%. The technical performances of the second process appear to be less attractive but with a lower energetic and ethanol consumption. Thus secondly the environmental impacts (water consumption and CO 2 emission) of the ultrafiltration step were quantified. Life Cycle Assessment data (Ecoinvent) were used to convert materials used for the infrastructure and energy consumed during functioning into carbon dioxide emissions and water consumptions. Results have shown that environmental impacts due to the operating conditions are higher than those relative to raw material involved in the installation. The study showed that this kind of approach allows the determination of optimum conditions for the ultrafiltration step.