Stabilization of aroma compounds through sorption-release by packaging polymers

Plastic packaging materials are often associated to aroma losses and to a decrease of the organoleptic quality of foods. This work defines situations where, on the contrary, plastics play a regulating role on the concentration of reactive aroma compounds in foods. These systems can be described by a two step mechanism; first, aroma is sorbed in the polymer, while the fraction in solution degrades quickly; in a second step, as the concentration is close to zero in the solution, the polymer liberates progressively the sorbed aroma back to the food. A simple numerical model is proposed, describing competitive processes of aroma degradation in solution and sorption by a polymer in contact with a homogeneous aqueous food. The classical limonene/low density polyethylene (LDPE) system is studied experimentally for the validation of the model: in an acidic medium, limonene both degrades quickly and is sorbed quickly, with a large solubility in LDPE. To define which aroma packaging systems could also display this interesting behavior, all types of possible interactions, using thermodynamic and kinetic parameters describing most practical situations, are simulated. For that purpose, 35 values of reference diffusion coefficients and 35 partition coefficients of usual aroma compounds between polymers and water have been measured and combined with the few available data from literature. The situations where polymers regulate the aroma concentration in food correspond to large partition coefficients (above 10), large diffusion coefficients (>10(-9) cm2 x s(-1)), and large degradation constants.     

Immersive landscapes: modelling ecosystem reference conditions in virtual reality

Landscape Ecology - Understanding the variability and dynamics of ecosystems, as well as their responses to climate or land use change, is challenging for policy makers and natural resource...     

Consumption of a functional fermented milk containing collagen hydrolysate improves the concentration of collagen-specific amino acids in plasma

Clinical studies have shown that collagen hydrolysate (CH) may be able to protect joints from damage, strengthen joints, and reduce pain from conditions like osteoarthritis. CH is a collection of amino acids and bioactive peptides, which allows for easy absorption into the blood stream and distribution in tissues. However, although various matrices have been studied, the absorption of specific amino acids from CH added to a fresh fermented milk product (FMP) was not studied. The primary objective of the present study was to compare the plasma concentrations of four representative amino acids from the CH (glycine, proline, hydroxyproline, and hydroxylysine) contained in a single administration of a FMP with that of a single administration of an equal amount of neat hydrolyzed collagen. These four amino acids were chosen because they have already been used as markers of CH absorption rate and bioavailability. This was a single-center, randomized open, and crossover study with two periods, which was performed in 15 healthy male subjects. The subjects received randomly and in fasted state a single dose of product 1 (10 g of CH in 100 mL of FMP) and product 2 (10 g of CH dissolved in 100 mL of water) separated by at least 5 days. After administration, the subjects were assessed for plasma concentrations of amino acids and for urine concentrations of hydroxyproline. After FMP administration, mean values of the maximal concentration (Cmax) of the four amino acids were greater than after ingredient administration (p < 0.05). This effect was related to an increased Cmax of proline (p < 0.05). In conclusion, because of their physicochemical characteristics, the fermentation process, and the great homogeneity of the preparation, this milk product improves the plasma concentration of amino acids from CH, that is, proline. The present study suggests an interesting role for FMP containing CH to improve the plasmatic availability of collagen-specific amino acids. Hence, this FMP product could be of potential interest in the management of joint diseases.     

Determination of coenzyme Q10 and Q9 in vegetable oils

A new sensitive and selective method has been developed for the quantification of the total coenzyme Q9 (CoQ9) and coenzyme Q10 (CoQ10) concentration in vegetable oil samples. The coenzyme Q fraction is isolated by solid-phase extraction (SPE) on amino phase eluting with a mixture of heptane:ethyl ether. The organic solvent is evaporated under nitrogen, and the residue is dissolved in a mixture of acetonitrile:tetrahydrofuran and finally is analyzed by reverse-phase high-performance liquid chromatography with a mass detector. The sensitivity of the method is based on the high efficient formation of the radical anions [M (-.)] of CoQ9 and CoQ10 by negative atmospheric pressure ionization. Interferences are minimized by using mass detection of the [M (-.)] ions ( m/ z = 797.5 for CoQ9 and m/ z = 862.5 for CoQ10) in selective reaction monitoring mode ( m/ z = 797.5 --> m/ z = 779.5 and m/ z = 862.5 --> m/ z = 847.5) using a triple-quadrupole mass spectrometer. The method was successfully applied to sunflower, soybean, and rapeseed oils, with a limit of quantification of 0.025 mg/kg for both compounds.     

Giant ringlike radio structures around galaxy cluster Abell 3376

In the current paradigm of cold dark matter cosmology, large-scale structures are assembling through hierarchical clustering of matter. In this process, an important role is played by megaparsec (Mpc)-scale cosmic shock waves, arising in gravity-driven supersonic flows of intergalactic matter onto dark matter-dominated collapsing structures such as pancakes, filaments, and clusters of galaxies. Here, we report Very Large Array telescope observations of giant ( approximately 2 Mpc by 1.6 Mpc), ring-shaped nonthermal radio-emitting structures, found at the outskirts of the rich cluster of galaxies Abell 3376. These structures may trace the elusive shock waves of cosmological large-scale matter flows, which are energetic enough to power them. These radio sources may also be the acceleration sites where magnetic shocks are possibly boosting cosmic-ray particles with energies of up to 10(18) to 10(19) electron volts.     

Optimizing metamorphosis in <Emphasis Type="Italic">Paracentrotus lividus</Emphasis> aquaculture using alternative macroalgae species to <Emphasis Type="Italic">Corallina</Emphasis> sp.

Metamorphosis induction cues (by chemical mediation or direct contact) were tested in Paracentrotus lividus using three different macroalgae treatments: Corallina sp., Palmaria palmata, and Laminaria digitata. Higher percentages of metamorphosis were reached in Paracentrotus lividus larvae by direct contact with a Palmaria palmata substrate.     

High‐resolution modelling of ocean circulation can reveal retention spots important for biodiversity conservation

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Effects of drought on weed emergence and growth vary with the seed burial depth and presence of a cover crop

In conservation agriculture, weed seed germination could decrease with the presence of a cover crop, surface weed seed location and temporal drought in summer just after seed shedding. This study simultaneously examined the effects of a cover crop, burial depth (seed location) and hydric stress on weed emergence and early growth. It was hypothesized that drought would reduce weed emergence and the initial growth of weed seeds and that this effect would be greater when the seeds were on the soil surface and in the presence of a cover crop. Four annual weed species were chosen that are frequently found (Anisantha sterilis, Vulpia myuros, Sonchus asper, Veronica persica) and not frequently found (Alopecurus myosuroides, Poa annua, Cyanus segetum, Capsella bursa‐pastoris) in fields that implement conservation agriculture. The unburied seeds had 26% lower emergence, on average, than the buried seeds (significant for six of the eight species), hydric stress reduced emergence by 20% (for seven of the eight species) and the presence of a cover crop reduced the level of emergence by 17% (for all species). The unburied seeds with hydric stress were emerging under the “most stressful” set of factors, with a 45% decrease in emergence, compared with the seeds emerging under the “least stressful” set of factors (buried seeds without hydric stress). All the weed growth measurements (height, dry matter content and number of leaves) decreased with the presence of a cover crop. The species that are found frequently in the fields that implement conservation agriculture, compared with the species that are not frequently found in conservation agriculture fields, had higher rates of germination and a higher tolerance of hydric stress when their seeds were unburied.