Emulsifying properties of legume proteins at acidic conditions: Effect of protein concentration and ionic strength

Postprint de http://freepaper.me/PDF/?pdfURL=aHR0cHM6Ly9mcmVlcGFwZXIubWUvbi9qNTdpWjNMejV0OXhlNzYxS1diN09BL1BERi85ZS85ZWIyMzBmYWU2ZWI1ZDg2OGIyM2FjM2U4MDA3NGEyNy5wZGY=&doi=10.1016/j.lwt.2015.10.051This work is focused on emulsifying properties of pea, chickpea and lentil protein isolates at acidic conditions (pH 3), as affected by protein concentration and ionic strength. Emulsions characteristics and stability (droplet size distribution, flocculation, coalescence and creaming) were determined. The microstructure of selected emulsions was also studied. Results indicated that emulsifying properties (ability and stability) are dependent to protein concentration and highly sensitive to ionic strength. In our conditions, the best emulsifying properties are found around 1.5% of protein, and at less than 50 mM of NaCl. Clearly, ionic strength affects emulsions microstructure. Thus, this study indicated that pea, chickpea and lentil proteins would have great potential as emulsifiers in acidic food formulations.Universidad de BéjaiaUniversidad de SevillaMicroscopy Service (CITIUS-Universidad de Sevilla

Chemical Composition and Biological Activities of Mentha Species

The genus Mentha L. (Lamiaceae) is distributed all over the world and can be found in many environments. Mentha species, one of the world’s oldest and most popular herbs, are widely used in cooking, in cosmetics, and as alternative or complementary therapy, mainly for the treatment of gastrointestinal disorders like flatulence, indigestion, nausea, vomiting, anorexia, and ulcerative colitis. Furthermore, it is well documented that the essential oil and extracts of Mentha species possess antimicrobial, fungicidal, antiviral, insecticidal, and antioxidant properties. The economic importance of mints is also evident; mint oil and its constituents and derivatives are used as flavoring agents throughout the world in food, pharmaceutical, herbal, perfumery, and flavoring industry. To provide a scientific basis for their traditional uses, several studies have been conducted to determine the chemical composition of mints and assess their biological activities. This chapter describes the therapeutic effects and uses of Mentha species and their constituents, particularly essential oils and phenolic compounds; some additional biological activities will also be considered

Modeling and Simulation of the Deactivation by Sintering of the Cobalt Catalyst during the Fischer-Tropsch Reaction

In the present work, the deactivation by sintering of cobalt based catalyst during Fischer-Tropsch synthesis at low temperature was studied by numerical simulation. For this purpose, a mathematical model was developed. The obtained simulation results allowed us to highlight and improve the understanding of the deactivation phenomena of cobalt based Fischer-Tropsch catalysts by sintering. The main results also show that the sintering phenomenon is strongly dependent on the operating conditions, in particular, the temperature, the pressure, and the H2/CO molar ratio, as well as the reaction by- products such as water. The results obtained can, therefore, be used to understand more the sintering mechanism which may be linked to the change in the concentration of the active sites and the reaction rates

Phenolic composition, in vitro antioxidant effects and tyrosinase inhibitory activity of three Algerian Mentha species: M. spicata (L.), M. pulegium (L.) and M. rotundifolia (L.) Huds (Lamiaceae)

International audienceThe leaves of three Mentha species harvested in Algeria, Mentha spicata L. (MS), Mentha pulegium L. (MP) and Mentha rotundifolia (L.) Huds (MR) were examined for their content in polyphenols and for some activities-linked biological properties these could impart. The contents in total phenolics (TPC) and flavonoids (TFC) were evaluated by the Folin–Ciocalteu and the aluminum chloride methods, respectively. Whereas MS showed the highest TPC (12.0 ± 0.3 mg gallic acid equivalents/g of dry weight), MR had the highest content in TFC (3.3 ± 0.1 mg quercetin equivalents of dry weight). The pharmacological properties of these extracts were evaluated by assessing in vitro their antioxidant and antityrosinase activities. The modulation of mushroom tyrosinase activity was measured by colorimetry of the melanins formed in the presence of tyrosine. MS exhibited the strongest radical scavenging activity (RSA) in all assays: (i) the IC50s values to neutralize the 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) cation radicals (ABTS+) and the 2,2′-diphenyl-1-picrylhydrazyl radicals (DPPH) were 10.3 ± 0.9 and 16.2 ± 0.2 μg/mL, respectively; and (ii) its original electrochemically measured superoxide quenching index value is 188 ± 37 μg/mL (AI50). MR however showed the highest tyrosinase inhibitory activity (IC50 = 108 ± 20 μg/mL). A silica gel thin-layer chromatography (TLC) technique revealed the presence of caffeic and rosmarinic acids and diosmin in all extracts. These results were confirmed by high performance liquid chromatography with diode array detection (HPLC/DAD

Method to build a generalized table of parameters in engineering design of technical systems: Lattice structure as a case study

Design parameters are a crucial element of the product design process. However, design parameter models are often used to solve specific design problems. Generalizing design parameters is an approach to tackle more design problems. This study contributes to resolving certain limitations associated with modeling and representing the design parameters. This paper presents a generalized table of parameters (GTP) for modeling system parameters. This table is linked to a contextual database based on data and information collected from scientific databases, experts' interviews, and Computer-Aided Design (CAD) and Finite Element Modeling (FEM) software analysis and usage. The proposed representative table shows the robustness of integrating multiple sources of information to present a holistic and generalized view of the design system. The quality of the provided data in the table is assessed by applying certain evaluating dimensions and indicators. A case study will be presented on the lattice structure within a specific context in the mechanical field

Phenolic compounds, antioxidant and antibacterial activities of three Ericaceae from Algeria

International audienceHerbs of the Ericaceae family are commonly found in Algeria and used in traditional medicine as antiseptic, diuretic, astringent, depurative, and to treat scalds and wounds. The methanolic extracts of three species, Arbutus unedo L. (A. unedo, leaves), Erica arborea L. (E. arborea, flowered aerial parts), and Erica multiflora L. (E. multiflora, flowered aerial parts), were compared regarding their content in phenolic compounds, their antioxidant, and antibacterial activities. A. unedo harbors the highest content in total phenolics and flavonoids, followed by E. arboreaE. multiflora. The contents in total phenolics and flavonoids showed a correlation with the measured antioxidant (hydrogen-donating) activities; this was particularly the case for flavonoids content. The A. unedo extract showed antibacterial activity against all the tested strains (Staphylococcus aureus ATCC 6538, S. aureus C100459, Escherichia coli ATCC 25922, and Pseudomonas aeruginosa ATCC 9027); however, the E. arborea and E. multiflora extracts showed antibacterial activity only against Gram positive bacteria. Some polyphenols were identified in the three herbs by thin-layer chromatography and high-performance liquid chromatography coupled with diode array and mass spectrometry detection; from these, caffeic acid, p-coumaric acid, naringin, quercetin and kaempferol are reported for the first time in E. multiflora

Serum Total Homocysteine Level in Association with Folate and Vitamin B12 Status Among Algerian Prostate Cancer Patients

Background: Folate, vitamin B12 and homocysteine are essential for methyl group metabolism and thus also for DNA methylation and metabolic disorders may lead to carcinogenesis metabolic disorders, which may lead to carcinogenesis. In the present study, we proposed to evaluate the associations between folate and vitamin B12, with fasting plasma tHcy concentration in prostate cancer (PCa) patients. Methods: A case –control study was conducted with 40 newly patients with prostate cancer diagnosed with prostate cancer and 50 age matched healthy controls. Serum level of total homocysteine, folate and vitamin B12 were measured by enzyme conversion immunoassay and radioassay, respectively using the ARCHITECT system (both Abbott–Diagnostics Division). Results: The average rate of total PSA was 20.97 ng / ml (ranged between 8- 60 ng / ml). 53% of patients had a PSA≥20ng/ml. Histology confirmed that all patients accounted for prostatic adenocarcinoma with prognostic Gleason score that ranged between 7 and 8 . There are no significant differences between cases and controls about serum Hcy levels (adjusted OR = 0.160% CI = 0.832-1.031), folate levels (adjusted OR = 0.428% CI  = 0.977-1.008) and vitamin B12 (adjusted OR = 0.103% CI  = 0.992-1.001). Conclusion: In this study, the results show that homocysteine is not involved in prostate cancer. However, this study shows that the sporadic form is much more prevalent than familial one. The diagnosis is often made too late in advanced stage with a high PSA levels and biopsy showing high levels of Gleaso

LEÓN, JOSÉ CLAUDIO DE Y SRA. [Material gráfico]

Copia digital. Madrid : Ministerio de Educación, Cultura y Deporte, 201

Polyphénols de l'alimentation (extraction, pouvoir antioxydant et interactions avec des ions métalliques)

Les polyphénols sont des métabolites secondaires de végétaux abondants dans l alimentation. Les extraire dans des conditions efficaces et mieux comprendre leurs propriétés physico-chimiques modulant leurs activités possibles dans le tractus digestif, constituent des enjeux scientifiques importants qui sont à la base de ce travail. La première partie porte sur l enrichissement de l huile d olive en polyphénols par transfert direct de ces derniers des feuilles d olivier à l huile, sous irradiation ultrasonore en comparaison avec une macération conventionnelle. Après optimisation des paramètres d extraction, la technique sous-ultrason à 16C s est révélée plus efficace que le procédé conventionnel du laboratoire (réacteur de 3 L) à l échelle pilote industriel (réacteur de 30L). Dans la seconde partie, la réactivité de polyphénols communs et représentatifs des principales classes(rutine, quercétine, catéchine, acide chlorogénique et phénols de l olive) avec le radical DPPH et les ions de métaux de transition d intérêt biologique(FeII, FeIII, CuI, CuII), a été étudiée par spectroscopie UV-visible (études cinétiques), par CLUP-SM (analyse de produits d oxydation) et au moyen des tests colorimétriques permettant de préciser l état redox des ions métalliques. L étude de l activité antiradicalaire (test DPPH ) en milieu micellaire aqueux a confirmé la capacité antioxydante des polyphénols sélectionnés en présence et en absence de la protéine sérum albumine bovine (SAB) etd un modèle d amidon (β-cyclodextrine). L étude de la capacité des composés phénoliques à complexer les ions métalliques, en solution faiblement acide (pH= 5-6), a suggéré que les flavonols et acides hydroxycinnamiques sont susceptibles de complexer Fe III dès le compartimen tgastrique quand le pH est faiblement acide (1-2 h après le repas). Par contre, l interaction avec Fe II et les ions du cuivre est probablement négligeable.L interaction Fe III polyphénol conduit à des complexes stables (sans oxydation notable du polyphénol) mais peut être inhibée par les interactionspolyphénol-protéinePolyphénols are plant secondary metabolites which are abundant in the diet. Their extraction using efficient processes and a better understanding of their physico-chemical properties that modulate their possible activities in the gastric tract are important scientific goals which underline this work. The first part deals with the direct enrichment of olive oil in polyphénols of olive leaves under ultrasonic irradiation in comparison with conventional maceration. After optimization of extraction parameters, the ultrasound-assisted process came up as more efficient than the conventional method at laboratory (reactor 3 L) to industrial pilot scale (reactor 30L). In the second part, the reactivity of some polyphenols, both common an representative ot the main classes (rutin, quercetin, catechin, chlorogenic acid and olive phenols) with DPPH radical and transition metal ions of biological interest (FeII, FeIII, CuI, CUII) was studied by UV-visible spectroscopy (kinetic studies), UPLC-MS (analysis of oxidation products) and via colorimetric tests for the determination of the redox state of the metal ions.The study of the antiradial activity (DPPH test) in aqueous micellar medium confirmed the antioxidant capacity of selected polyphenols in the presence and absence of bovine serum albumin (BSA) protein and a starch model (b-cyclodextrin). The study of the ability of phenolic compounds to bind metal ions in weakly acidic solution(pH=5-6), suggested that flavonols and hydroxycinnamic acids are able to complex FeIII from the gastric compartment when pH is slightly acid (1-2 h after the meal). However, interaction with FeII and copper ions is probably negligible. Interaction FeIII-polyphenol leads to stable complexes (without significant oxidation ot he polyphenol), but can be inhibited by the polyphenol-protein interactionsAVIGNON-Bib. numérique (840079901) / SudocSudocFranceF