Protein Interactions / assemblies and subsequent properties

Protein Interactions / assemblies and subsequent properties. STLOpenday

β-Lactoglobulin-linoleate complexes: In vitro digestion and the role of protein in fatty acids uptake

peer-reviewedThe dairy protein β-lactoglobulin (BLG) is known to bind fatty acids such as the salt of the essential longchain fatty acid linoleic acid (cis,cis-9,12-octadecadienoic acid, n-6, 18:2). The aim of the current study was to investigate how bovine BLG-linoleate complexes, of various stoichiometry, affect the enzymatic digestion of BLG and the intracellular transport of linoleate into enterocyte-like monolayers. Duodenal and gastric digestions of the complexes indicated that BLG was hydrolyzed more rapidly when complexed with linoleate. Digested as well as undigested BLG-linoleate complexes reduced intracellular linoleate transport as compared with free linoleate. To investigate whether enteroendocrine cells perceive linoleate differently when part of a complex, the ability of linoleate to increase production or secretion of the enteroendocrine satiety hormone, cholecystokinin, was measured. Cholecystokinin mRNA levels were different when linoleate was presented to the cells alone or as part of a protein complex. In conclusion, understanding interactions between linoleate and BLG could help to formulate foods with targeted fatty acid bioaccessibility and, therefore, aid in the development of food matrices with optimal bioactive efficacyS. Le Maux is currently supported by a Teagasc Walsh Fellowship and the Department of Agriculture, Fisheries and Food (FIRM project 08/RD/TMFRC/650). We also acknowledge funding from IRCSET-Ulysses Travel Grant

From’Innov: a new concept for building cheese texture and taste separately for design-on-demand and short supply

Combined steps, such as draining and acidification, as well as ripening downtime still represent bottlenecks during cheese making. Indeed, they negatively affect the control of process efficiency, the cheese weight range, the quality of by-products and the balance between supply and demand. In this work, an innovative process was proposed and validated on a semi-industrial scale in order to manufacture cheese products without ripening, albeit on a large range of texture and taste mimicking fresh to pressed type cheeses. On the one hand, draining and acidification steps were uncoupled by using membrane filtration and centrifugation to fractionate milk constituents, and then by reconstructing a controlled texture matrix with regard to protein / fat ratio, denaturation rate of whey proteins, mineralization and amount of available lactose.Different aromatic matrices were produced in parallel by growing Yarrovia lipolytica, Propionibacterium freudenreichii, a mixture of Lactococcus lactis / cremoris / diacetylactis, or Hafnia alvéi in controlled environmental conditions. In less than four days, aromatic sulfur, ketone, acidic and aldehyde molecules were produced at concentration similar to that of a ripened curd. Finally, the texture and aromatic matrices were assembled in a ratio 90:10, and then textured through pH and temperature adjustment, NaCl, rennet or texturing agent addition. Results showed it was possible to obtain products with firmness varying from that of a spread cheese to that of a semi hard type cheese, and with aroma mimicking Saint Paulin as well as Cheddar depending on the quantities and proportions of added aromatic molecules.This eco-efficient and patented process makes it possible to control each step independently, to reduce significantly the inputs, to obtain standardized by-products and consequently to limit production costs. It is possible with the same equipment to produce from day to day and on demand any types of flavored and textured cheeses

Minéraux, cycles thermiques de faibles intensités et coagulation du lait

Questions de rechercheQ1 : Les itinéraires thermiques affectent ils les propriétés fonctionnelles des laits?Q2 : Si oui, quelles en sont les bases physicochimiques ?Q3 : Les modifications physicochimiques et technofonctionnelles sont elles réversibles et quelles sont les cinétiques de « réversibilité »

A tutela penal do ambiente e a responsabilidade penal da pessoa jurídica por crimes ambientais

Prof. Mestre Andrea Regina de Morais Benedetti - OrientadoraMonografia (especialização) - Universidade Federal do Paraná, Setor de Ciências Agrárias, Curso de Especialização em Direito AmbientalInclui referênciasResumo : O presente trabalho pretende demonstrar a importância da tutela penal do meio ambiente no âmbito da responsabilidade penal da pessoa jurídica por crimes ambientais, demonstrando a aplicação dos princípios do direito ambiental explícitos ou implícitos no ordenamento jurídico. Pretende-se, ainda, demonstrar a necessidade de criminalização da pessoa jurídica que comete dano ambiental, tendo em vista a relevância do ambiente ecologicamente equilibrado para a humanidade. Para tanto, inicialmente foi abordado sobre os interesses coletivos, difusos e individuais homogêneos, estabelecendo a correta classificação do bem ambiental. Na sequência foram trazidos os principais princípios de direito ambiental: princípio do desenvolvimento sustentável; prevenção e precaução; poluidor-pagador; usuário-pagador; participação popular; informação; função socioambiental da propriedade; educação ambiental e vedação do retrocesso ecológico. Princípios estes norteadores da efetiva aplicação do direito do ambiente. Logo após, foram trazidos alguns princípios que envolvem o direito penal e sua relação e aplicação na seara ambiental, bem como as críticas doutrinárias acerca do tema, tais como o princípio da insignificância, da legalidade ou reserva legal, da intervenção mínima e do NE bis in idem, da adequação social, da irretroatividade da lei penal e da proporcionalidade, bem como tratou-se da norma penal em branco e sua relação com o direito ambiental. Por último, tratou-se do direito penal ambiental, demonstrando a autonomia do bem jurídico meio ambiente e ainda explicitando os fundamentos da tutela penal do meio ambiente, além de breves traços sobre a lei de crimes ambientais. Em conclusão, observou-se a necessidade de se tutelar criminalmente o meio ambiente, tendo em vista tratar-se de um bem jurídico de relevo. O método utilizado foi o hipotético-dedutivo com técnica de revisão bibliográfica

Kinetics of heat-induced denaturation of whey proteins and characterization of protein aggregates in model infant formulas

In 2018, about 60% of world’s newborns received cow milk-based infant formulas (IF) instead of human milk (UNICEF). The process of manufacturing IF involves heat treatments altering the physicochemical properties of milk components, especially whey proteins (WP), and so the rheological properties of IF. The objective of the study was to investigate the impacts of thermal treatments on the denaturation of WP of IF, particularly for those mimicking the protein profile of human milk, and to characterize the heat-induced protein structures.Three model IF were produced with a caseins:WP ratio of 40:60 at 1.3% and 5.5% of total proteins, i.e. the protein contents at which are applied heat treatments during the manufacture of liquid or powder IF, respectively. Skimmed milk was mixed with a WP isolate, a mix of WP isolate and purified lactoferrin or a mix of both purified lactoferrin and α-lactalbumin in proportion similar to that in human milk. The kinetic of heat-induced denaturation of each WP was investigated between 67.5°C and 80°C by RP-HPLC. The heat-induced protein structures were studied by dynamic light scattering, electrophoresis and asymmetric flow field flow fractionation coupled with MALLS.The results revealed that the extent of denaturation of WP depended on the protein content and the nature of the WP within the IF. IF at 5.5% of proteins and containing β-lactoglobulin gelled for longer heating time at 80°C. At similar rate of total WP denaturation at 67.5°C and 80°C, the protein composition of the heat-induced aggregates changed between formulas, protein concentrations and heating temperatures but disulfide bonds were the main intermolecular links. The aggregates were larger and of fractal shape (dfapp=2.1) in formulas at 5.5% proteins whereas they were of spherical shape (dfapp=2.9) in formulas at 1.3% proteins.These results will give to industrials reliable data on the protein structures formed during the heat treatments of IF. The impact on digestibility will be subsequently investigated

The role of Ovotransferrin in egg-white antimicrobial activity: a review

Eggs are a whole food which affordably support human nutritional requirements worldwide. Eggs strongly resist bacterial infection due to an arsenal of defensive systems, many of which reside in the egg white. However, despite improved control of egg production and distribution, eggs remain a vehicle for foodborne transmission of Salmonella enterica serovar Enteritidis, which continues to represent a major public health challenge. It is generally accepted that iron deficiency, mediated by the iron-chelating properties of the egg-white protein ovotransferrin, has a key role in inhibiting infection of eggs by Salmonella. Ovotransferrin has an additional antibacterial activity beyond iron-chelation, which appears to depend on direct interaction with the bacterial cell surface, resulting in membrane perturbation. Current understanding of the antibacterial role of ovotransferrin is limited by a failure to fully consider its activity within the natural context of the egg white, where a series relevant environmental factors (such as alkalinity, high viscosity, ionic composition, and egg white protein interactions) may exert significant influence on ovotransferrin activity. This review provides an overview of what is known and what remains to be determined regarding the antimicrobial activity of ovotransferrin in egg white, and thus enhances understanding of egg safety through improved insight of this key antimicrobial component of eggs

Multidisciplinary investigation on cold seeps with vigorous gas emissions in the Sea of Marmara (MarsiteCruise): Strategy for site detection and sampling and first scientific outcome

MarsiteCruise was undertaken in October/November 2014 in the Sea of Marmara to gain detailed insight into the fate of fluids migrating within the sedimentary column and partially released into the water column. The overall objective of the project was to achieve a more global understanding of cold-seep dynamics in the context of a major active strike-slip fault. Five remotely operated vehicle (ROV) dives were performed at selected areas along the North Anatolian Fault and inherited faults. To efficiently detect, select and sample the gas seeps, we applied an original procedure. It combines sequentially (1) the acquisition of ship-borne multibeam acoustic data from the water column prior to each dive to detect gas emission sites and to design the tracks of the ROV dives, (2) in situ and real-time Raman spectroscopy analysis of the gas stream, and (3) onboard determination of molecular and isotopic compositions of the collected gas bubbles. The in situ Raman spectroscopy was used as a decision-making tool to evaluate the need for continuing with the sampling of gases from the discovered seep, or to move to another one. Push cores were gathered to study buried carbonates and pore waters at the surficial sediment, while CTD-Rosette allowed collecting samples to measure dissolved-methane concentration within the water column followed by a comparison with measurements from samples collected with the submersible Nautile during the Marnaut cruise in 2007. Overall, the visited sites were characterized by a wide diversity of seeps. CO2- and oil-rich seeps were found at the westernmost part of the sea in the Tekirdag Basin, while amphipods, anemones and coral populated the sites visited at the easternmost part in the Cinarcik Basin. Methane-derived authigenic carbonates and bacterial mats were widespread on the seafloor at all sites with variable size and distributions. The measured methane concentrations in the water column were up to 377 μmol, and the dissolved pore-water profiles indicated the occurrence of sulfate depleting processes accompanied with carbonate precipitation. The pore-water profiles display evidence of biogeochemical transformations leading to the fast depletion of seawater sulfate within the first 25-cm depth of the sediment. These results show that the North Anatolian Fault and inherited faults are important migration paths for fluids for which a significant part is discharged into the water column, contributing to the increase of methane concentration at the bottom seawater and favoring the development of specific ecosystems

Thermal plasma synthesis of Li2S nanoparticles for application in lithium-sulfur batteries

Abstract : Inductively-coupled thermal plasma processes were used to produce nanosized Li2S. Prior to the syntheses, the feasibility of forming Li2S was first evaluated using FactSage by considering the phase diagrams of sulfur and different lithium precursors in reducing atmospheres; Li2O, LiOH·H2O, Li2CO3 and Li2SO4·H2O all showed promises in producing Li2S nanoparticles, as confirmed by experiments. Argon and hydrogen mixtures were used as plasma gases, and a carbothermal reduction was implemented for Li2SO4·H2O. In addition, carbon-coated Li2S nanoparticles were synthesized with downstream injection of methane. Carbon was shown to stabilize Li2S upon contact with ambient air. The Li2S nanoparticles were electrochemically tested in half-cells using electrolytes containing LiNO3 or Li2S6 as additives. It was found that adding LiNO3 to the electrolyte was detrimental to the electrochemical performance of Li2S, whereas the combination of Li2S6 and LiNO3 as additives doubled the charge and discharge capacities of the half-cell over 10 cycles