The magnesium sulfate-water system at pressures to 4 kilobars

Hydrated magnesium sulfate constitutes up to 1/6 of the mass of carbonaceous chondrites, and probably is important in many icy asteroids and satellites. It occurs naturally in meteorites mostly as epsomite. MgSO4, considered anhydrously, comprises nearly 3/4 of the highly soluble fraction of C1 chondrites. Thus, MgSO4 is probably an important solute in cryovolcanic brines erupted on certain icy objects in the outer solar system. While the physiochemical properties of the water-magnesium sulfate system are well known at low pressures, planetological applications of these data are hindered by a dearth of useful published data at elevated pressures. Accordingly, solid-liquid phase equilibria was recently explored in this chemical system at pressures extending to about 4 kilobars. The water magnesium sulfate system in the region of the eutectic exhibits qualitatively constant behavior between pressures of 1 atm and 2 kbar. The eutectic melting curve closely follows that for water ice, with a freezing point depression of about 4 K at 1 atm decreasing to around 3.3 K at 2 kbars. The eutectic shifts from 17 pct. MgSO4 at 1 atm to about 15.3 pct at 2 kbars. Above 2 kbars, the eutectic melting curve again tends to follow ice

Impact of Extending Hard-Cheese Ripening : A Multiparameter Characterization of Parmigiano Reggiano Cheese Ripened up to 50 Months

Extending ripening of hard cheeses well beyond the traditional ripening period is becoming increasingly popular, although little is known about the actual evolution of their characteristics. The present work aimed at investigating selected traits of Parmigiano Reggiano cheese ripened for 12, 18, 24, 30, 40 and 50 months. Two cheeses per each ripening period were sampled. Although moisture constantly decreased and was close to 25% in 50-month cheeses, with a parallel increase in cheese hardness, several biochemical changes occurred involving the activity of both native and microbial enzymes. Capillary electrophoresis demonstrated degradation of \u3b1s1- and \u3b2-casein, indicating residual activity of both chymosin and plasmin. Similarly, continuous release of free amino acids supported the activity of peptidases deriving from lysed bacterial cells. Volatile flavor compounds, such as short-chain fatty acids and some derived ketones, alcohols and esters, evaluated by gas chromatography with solid-phase micro-extraction, accumulated as well. Cheese microstructure was characterized by free fat trapped in irregularly shaped areas within a protein network, with native fat globules being no longer visible. This study showed for the first time that numerous biochemical and structural variations still occur in a hard cheese at up to 50 months of aging, proving that the ripening extension deserves to be highlighted to the consumer and may justify a premium price

Phase equilibria of the magnesium sulfate-water system to 4 kbars

Magnesium sulfate is the most abundant salt in carbonaceous chondrites, and it may be important in the low-temperature igneous evolution and aqueous differentiation of icy satellites and large chondritic asteroids. Accordingly, we are investigating high-pressure phase equilibria in MgSO4-H2O solutions under pressures up to four kbars. An initial report was presented two years ago. This abstract summarizes our results to date including studies of solutions containing 15.3 percent, 17 percent, and 22 percent MgSO4. Briefly, these results demonstrate that increasing pressure causes the eutectic and peritectic compositions to shift to much lower concentrations of magnesium sulfate, and the existence of a new low-density phase of magnesium sulfate hydrate

Circadian control of brown adipose tissue

Disruption of circadian (similar to 24 h) rhythms is associated with an increased risk of cardiometabolic diseases. Therefore, unravelling how circadian rhythms are regulated in different metabolic tissues has become a prominent research focus. Of particular interest is brown adipose tissue (BAT), which combusts triglyceride-derived fatty acids and glucose into heat and displays a circannual and diurnal rhythm in its thermogenic activity. In this review, the genetic, neuronal and endocrine generation of these rhythms in BAT is discussed. In addition, the potential risks of disruption or attenuation of these rhythms in BAT, and possible factors influencing these rhythms, are addressed.Diabetes mellitus: pathophysiological changes and therap

Macromolecular Traits in the African Rice Oryza glaberrima and in Glaberrima/Sativa Crosses, and Their Relevance to Processing

Molecular properties of proteins and starch were investigated in 2 accessions of Oryza glaberrima and Oryza sativa, and in one NERICA cross between the 2 species, to assess traits that could be relevant to transformation into specific foods. Protein nature and organization in O. glaberrima were different from those in O. sativa and in NERICA. Despite the similar cysteine content in all samples, thiol accessibility in O. glaberrima proteins was higher than in NERICA or in O. sativa. Inter-protein disulphide bonds were important for the formation of protein aggregates in O. glaberrima, whereas non-covalent protein-protein interactions were relevant in NERICA and O. sativa. DSC and NMR studies indicated only minor differences in the structure of starch in these species, as also made evident by their microstructural features. Nevertheless, starch gelatinization in O. glaberrima was very different from what was observed in O. sativa and NERICA. The content of soluble species in gelatinized starch from the various species in the presence/absence of treatments with specific enzymes indicated that release of small starch breakdown products was lowest in O. glaberrima, in particular from the amylopectin component. These findings may explain the low glycemic index of O. glaberrima, and provide a rationale for extending the use of O. glaberrima in the production of specific rice-based products, thus improving the economic value and the market appeal of African crops

Semantics-based information extraction for detecting economic events

As today's financial markets are sensitive to breaking news on economic events, accurate and timely automatic identification of events in news items is crucial. Unstructured news items originating from many heterogeneous sources have to be mined in order to extract knowledge useful for guiding decision making processes. Hence, we propose the Semantics-Based Pipeline for Economic Event Detection (SPEED), focusing on extracting financial events from news articles and annotating these with meta-data at a speed that enables real-time use. In our implementation, we use some components of an existing framework as well as new components, e.g., a high-performance Ontology Gazetteer, a Word Group Look-Up component, a Word Sense Disambiguator, and components for detecting economic events. Through their interaction with a domain-specific ontology, our novel, semantically enabled components constitute a feedback loop which fosters future reuse of acquired knowledge in the event detection process

Grated Grana Padano cheese : new hints on how to control quality and recognize imitations

The sensorial and physico-chemical characteristics described in the product specification for most PDO cheeses are inadequate to verify the compliance of cheeses on the market with the registered designation, particularly for grated products. During the past few years, much research has indicated the analytical parameters suitable for distinguishing Grana Padano (GP) from other similar hard cheeses. The characterization of grated GP is currently based on 3 analytical parameters, related to different aspects of cheese processing, which are: (i) the measurement of alkaline phosphatase (ALP) activity, a marker for possible heat treatment applied to milk, in the outermost layer of the cheese, just below the rind; (ii) the identification of specific peptides, that are identified only in the rind, due to the very slow progress of proteolysis in the rind during GP cheese ripening; and (iii) the free amino acid (FAA) composition. In the present study, we developed an extraction method, based on density gradient centrifugation of solubilized cheese, to separate the outermost layer of the cheeses from the rest in grated cheese, and we proposed a simplified criterion to evaluate the "typicalness" of the FAA pattern. The quality control scheme based on ALP activity, detection of specific peptides and FAA pattern was applied to more than 300 samples of marketed grated GP collected over three years, 10% of which were collected outside Italy, and 3c 100 samples of grated generic ("Grana-type") hard cheeses. The results demonstrate that the simultaneous application of the three parameters allows one to distinguish grated GP from similar, non-PDO grated hard cheeses, and to recognize irregular GP cheeses

New insight on crystal and spot development in hard and extra-hard cheeses : Association of spots with incomplete aggregation of curd granules

Chemical composition and structure of different types of macroparticles (specks, spots) and microparticles (microcrystals) present in hard and extra-hard cheeses were investigated. Light microscopy revealed that the small hard specks had the structure of crystalline tyrosine, as confirmed by amino acid analysis. Spots showed a complex structure, including several curd granules, cavities, and microcrystals, and were delimited by a dense protein layer. Spots contained less moisture and ash than the adjacent cheese area, and more protein, including significantly higher contents of valine, methionine, isoleucine, leucine, tyrosine, and phenylalanine. Microcrystals were observed by light and electron microscopy and analyzed by confocal micro-Raman. Among others, calcium phosphate crystals appeared to consist of a central star-shaped structure immersed in a matrix of free fatty acids plus leucine and phenylalanine in free form or in small peptides. A hypothetical mechanism for the formation of these structures has been formulated

Shedding light on crystals and white spots in cheese

Microscopy is a powerful research tool in food science, although a number of difficulties in sample preparation may discourage its use. Investigation at structure and ultrastructure level helps to understand changes and interactions the raw material components undergo when processed into food. We have adopted various microscopy techniques to study the nature and origin of different types of crystals and spots originating in hard cheeses during ripening. Although not directly affecting the flavor, in this type of cheese they are considered a desired attribute. Compositional, biochemical and microbiological data were obtained on the same samples to support the microscopy study. In hard cheeses upon ripening, protein is progressively degraded into free amino acids. After 10-12 month ripening, free amino acids represent more than 20% of the cheese protein. This fact largely contributes to increase the concentration of solutes in cheese water phase, where sodium chloride, calcium, phosphates, lactate and other soluble molecules are already present. Crystals of tyrosine, calcium lactate and calcium phosphate are already reported to occur in some cheese varieties, such as Cheddar, Gouda, Emmental, Grana Padano and Parmigiano-Reggiano, due to the decreased solubility as the cheese water content decreases. In addition, non-crystalline spherical spots are reported to occur in the last two cheeses, sometimes named as \u201cpearls\u201d and whose origin is not yet understood. We have focused our attention on those pearls and investigated their structure and ultrastructure for the first time. The matrix, as observed by both optical and confocal microscopy after suitable staining procedures, appeared to be rather homogeneous but more compact with respect to the surrounding cheese portion from which the pearl is clearly distinguishable, with several crystals embedded. By TEM of the resin embedded material, the crystals showed a star-shaped core surrounded by a thick layer of dense material. The nature of the different components of the crystals was further investigated by confocal microscopy, confocal Raman microscopy and compositional data, and a possible role of some free amino acids as seeding components was hypothesized

Proteolytic Activity and Production of γ-Aminobutyric Acid by Streptococcus thermophilus Cultivated in Microfiltered Pasteurized Milk

A set of 191 strains of Streptococcus thermophilus were preliminarily screened for the presence of the genes codifying for cell envelope-associated proteinase (prtS) and for glutamate decarboxylase (gadB) responsible for \u3b3-aminobutyric acid (GABA) production. The growth and proteolytic activity of the gadB-positive strains (9 presenting the prtS gene and 11 lacking it) were studied in microfiltered pasteurized milk. Degradation of both caseins (capillary electrophoresis) and soluble nitrogen fractions (HPLC) and changes in the profile of free amino acids (FAAs; ion-exchange chromatography) were evaluated at inoculation and after 6 and 24 h of incubation at 41 \ub0C. None of the strains was capable of hydrolyzing caseins and \u3b2-lactoglobulin, and only two hydrolyzed part of \u3b1-lactalbumin, these proteins being present in their native states in pasteurized milk. Contrarily, most strains were able to hydrolyze peptones and peptides. For initial growth, most strains relied on the FAAs present in milk, whereas, after 6 h, prtS+ strains released variable amounts of FAA. One prtS+ strain expressed a PrtS- phenotype, and two prtS- strains showed a rather intense proteolytic activity. Only five strains (all prtS+) produced GABA, in variable quantities (up to 100 mg/L) and at different rates, depending on the acidification strength. Addition of glutamate did not induce production of GABA in nonproducing strains that, however, unexpectedly were shown to adopt the degradation of arginine into citrulline and ornithine as an alternative acid resistance system and likely as a source of ATP