Determination of zearalenone and its metabolites in endometrial cancer by coupled separation techniques

This study presents a selective method of isolation of zearalenone (ZON) and its metabolite, α-zearalenol (α-ZOL), in neoplastically changed human tissue by accelerated solvent and ultrasonic extractions using a mixture of acetonitrile/water (84/16% v/v) as the extraction solvent. Extraction effectiveness was determined through the selection of parameters (composition of the solvent mixture, temperature, pressure, number of cycles) with tissue contamination at the level of nanograms per gram. The produced acetonitrile/water extracts were purified, and analytes were enriched in columns packed with homemade molecularly imprinted polymers. Purified extracts were determined by liquid chromatography (LC) coupled with different detection systems (diode array detection - DAD and mass spectrometry - MS) involving the Ascentis RP-Amide as a stationary phase and gradient elution. The combination of UE-MISPE-LC (ultrasonic extraction - molecularly imprinted solid-phase extraction - liquid chromatography) produced high (R ≈ 95–98%) and repeatable (RSD < 3%) recovery values for ZON and α-ZOL

Influence des événements tectono-sédimentaires sur l’évolution des foraminifères du Lias-Dogger dans la région d’Aïn Ouarka (Atlas saharien, Algérie)

Sebane Abbès, Mekahli Larbi, Benhamou Miloud, Tchenar S. Influence des événements tectono-sédimentaires sur l’évolution des foraminifères du Lias-Dogger dans la région d’Aïn Ouarka (Atlas saharien, Algérie). In: Documents des Laboratoires de Géologie, Lyon, n°156, 2002. STRATI 2002. 3ème congrès français de stratigraphie. Lyon, 8-10 juillet 2002. pp. 210-211

Effects of extraction solvents on phenolic contents and antioxidant activities of Tunisian date varieties (Phoenix dactylifera L.)

peer reviewedSecond-grade dates (Phoenix dactylifera L.), with hard texture, from six Tunisian cultivars were analysed for their composition and antioxidant activities. Results showed predominance of total sugars and a relatively low content of protein, fat andash. On the other hand, optimisation of extraction of antioxidant was carried using five different solvents. The highest level of phenolic compounds for all dates varieties was found in the 70% acetone extract. This level ranged from 199.43 to 576.48 mg of GAE/100 g fresh weight. However, extraction into 50% methanol gave the highest antioxidant activity from 89.55 to 109.67 mg equivalents of ascorbic acid/g fresh weight. For both two olvents, Bejo exhibited the highest phenolic content and total antioxidant activity, while Baydh El Hamam presented the owest. A positive linear correlation between total antioxidant activity and phenolic contents was observed (R2 = 0.83; R2 = 74 for acetone/H2O and methanol/H2O, respectively). The antioxidant activity of acetone/H2O and methanol/H2O extracts was carried using DPPH radical-scavenging activity and reducing power. These results showed that dates had strongly scavenging activity on DPPH reaching 90.12% in methanol/H2O from Deglet Nour. Whereas, acetone/H2O showed the best reducing power which Bejo was significantly higher than the other varieties. This study demonstrates the potential antioxidant activity with Tunisian date, that we can use these natural extracts as food additives in replacement of synthetic compounds

Analyse par simulation numérique de l’influence du facteur de correction sur les mesures de dureté de matériaux élasto-plastiques en indentation instrumentée

La détermination des propriétés mécaniques telles que la dureté et le module d’élasticité par indentation instrumentée repose essentiellement sur la relation de Sneddon, liant la rigidité de contact à la décharge Su, le module élastique réduit Er et l’aire de contact projetée Ac. Un facteur de correction β est généralement introduit dans cette relation : \hbox{$S_{u} =\beta 2 \sqrt{\pi}E_{r} \sqrt{A_{c}}$}. En pratique, ce dernier est supposé constant pour une géométrie d’indenteur donnée. Toutefois, des simulations numériques (MEF) d’essais d’indentation sur des matériaux élastiques ont mis en évidence la dépendance de β avec le rapport profondeur de pénétration/rayon de la pointe d’indentation (h/R). Nous nous intéressons ici à l’évolution de ce facteur de correction en fonction du rapport h/R dans le cas de matériaux élasto-plastiques. L’influence de la non-prise en compte de ce facteur β lors de la détermination de la dureté est notamment étudiée

Effect of processing conditions on phenolic compounds and antioxidant properties of date syrup

Commercial hydrolytic enzymes (pectinase and cellulase) were investigated for their influence on phenolics and antioxidant activities of date syrup. Content of total phenolics, flavonoids and carotenoids contents were determined spectrophotometrically. Polyphenols composition was examined using HPLC. Seven phenolic compounds (catechin, vanillic acid, caffeic acid, syringic acid, p-coumaric acid, ferulic acid and sinapic acid) were detected in all date syrup extracts. p-Coumaric acid was the major compound of all date syrup extracts, representing 49.223-63.397%. The antioxidant activity of date syrup was evaluated by various antioxidant assays, including total antioxidant, DPPH scavenging test, FRAP, hydrogen peroxide scavenging activity and metal chelating activity.Results showed that the date syrup prepared after extraction with pectinase and cellulase mixture gave the lowest phenolic and flavonoid contents. For same variety, date syrup prepared after extraction with pectinase and cellulase mixture gave the highest carotenoids amounts. The antioxidant activity, determined by several methods, was significantly affected by the extraction method as well as date varieties. In fact, the date syrup prepared after extraction with pectinase and cellulase mixture gave the lowest antioxidant activity. A good correlation between the antioxidant activity and total phenolic content and flavonoid was observed. The discovery of our research is very important to scientists as well as to the fruit-processing industry to produce juice and syrup with high antioxidant activity. © 2012 Elsevier B.V

Physicochemical, Functional and Antioxidant Properties of the Major Protein Fractions Extracted from Prickly Pear (Opuntia ficus indica L.) Seed Cake

peer reviewedAbstract: Proteins were extracted from a prickly pear seed cake using the Osborne extraction method. Physico-chemical, antioxidant and functional properties of the major protein fractions (albumin and glutelin) were studied. Glutelin fraction presented good amount of proteins (60.42% dry weight) with appreciable essential amino acids content (24.45% of total amino acids). The Fourier transform-infrared spectroscopy spectra showed between ~ 1200 and 1700 cm−1, characteristically peaks of proteins, namely, amide I, II and III for both fractions. Antioxidant activities of protein fractions were assessed in vitro through different antioxidant tests. The protein fractions exhibited good DPPH and metal scavenging activities. However, they demonstrated moderate reductive ability. Protein fractions had a minimum equilibrium surface tension at the isoelectric pH. They were characterized by interesting techno-functional properties such as emulsifying and foaming capacities which were affected by pH values. They also displayed significant water holding (480% for albumin fraction at pH 7) and oil holding (420% for glutelin at pH 7) capacities. The found results suggested that albumin and glutelin extracted from prickly pear seed cake could have important applications in food formulations. Graphic Abstract: [Figure not available: see fulltext.]. © 2020, Springer Nature B.V