Thermomechanically Induced Protein Aggregation and Starch Structural Changes in Wheat Flour Dough

Various studies have been carried out on wheat flour to understand protein and starch changes when subjected to mixing and temperature constraints, but structural changes of proteins and starch at the typical moisture levels of a dough system are not fully understood. The aim of this research was to improve our understanding of (micro)structural changes at the mesoscopic level, through empirical rheology, microscopy (light and scanning electron microscopy), sequential protein extractions, and glutenin macropolymer wet weight along the mixing, heating, and cooling stages of the Mixolab assay. Studies were performed on three wheat flours with different protein contents. The rheological analysis allowed identifying the role of the proteins and the relationship between the protein content and different primary and secondary parameters obtained from the recorded curves. The progressive heating and mixing stages during the Mixolab assay resulted in a dynamic de‐ and restructuring of proteins involving interactions between the flour proteins from water soluble to SDS soluble to SDS insoluble and vice versa. The microstructure analysis with light, polarized, and scanning electron microscopy revealed the changes that proteins and starch molecules underwent during mixing, heating, and cooling. Qualitatively, the starch structural changes, swelling, and gelatinization observed by microscopic techniques showed some parallels with protein (and glutenin) content of the respective flour. Nevertheless, this tentative finding needs further confirmation by studying flour samples with large differences in glutenin content.     

Using timed automata and model-checking to simulate material flow in agricultural production systems—Application to animal waste management

Due to intensification and specialisation of animal production and the increasing pressure of environmental regulations, the careful management of animal wastes becomes a key point for the sustainability of livestock farming. This paper addresses the dynamic representation of a network composed by a set of production units (i.e., livestock farms) that need to transfer their wastes to a set of consumption units (i.e., crops onto which wastes may be spread over). The dynamics of stocks (taken as continuous fluxes with imprecise parameters) is combined with management decisions or actions (taken as discrete events). Various temporal constraints determine the possibilities of waste transfers. For each production or consumption unit, these constraints are modelled as a timed automaton. Possible allocation of wastes is then analysed using model-checking techniques applied to the global timed automaton resulting from the product of all the elementary timed automata. To this end, the Kronos software based on the Timed Computational Tree Logic (TCTL) is used. Our approach is illustrated through the analysis of a typical farming system made of livestock and crop enterprises in the context of the Reunion Island. Using the computer tool implementing this approach, we show how an initial waste management policy can be improved by simulation to find a better waste allocation to crops.     

Contribution of Medicago sativa to the productivity and nutritive value of forage in semi‐arid grassland pastures

The inclusion of legumes in semi‐arid native grasslands may promote the productivity and nutritive value of forage. This study was designed to assess the effect of legumes (the introduced legume Medicago sativa or the native legume Dalea purpurea) and soil P fertility (addition of 0, 50, or 200 P₂O₅ kg/ha at seeding) on the dry matter and nutrient content of native grasses mixtures, compared with the commonly used introduced forage grass Bromus biebersteinii grown with M. sativa. Plant harvests were performed in September 2008, July 2009 and September 2009. Plants nutrient content, δ¹⁵N value and dry matter were analysed. Results show that the M. sativa enhanced the N and P concentrations of native grass mixtures early in the summer, as well as the N concentration in Bouteloua gracilis in late summer of the driest year, 2009. The higher AM fungal diversity promoted by M. sativa was positively correlated with the dry matter and nitrogen uptake of M. sativa and with the P concentration of native grasses, in early summer. Overall, this study shows that M. sativa promoted beneficial AM fungal taxa and improved forage production in the semi‐arid prairies.     

Chromium (VI) Retrieval from Chromium Ore Processing Residues by Electrokinetic Treatment

Electrokinetics (EK) was investigated as a possible technique for in-situ treatment of leachable chromium at a built site contaminated with chromium ore processing residues (COPR). A preliminary EK experiment was carried out at the laboratory scale on an undisturbed COPR core sample. Methods applied for material and pore water characterization before and after EK treatment addressed physical aspects by laser diffraction granulometry, pycnometry and pore water content, mineralogical aspects by X-ray diffraction, scanning electron microscopy coupled with energy dispersive X-ray spectroscopy, and chemical aspects by inductively coupled plasma-atomic emission spectroscopy and atomic absorption spectroscopy for elemental composition, spectrophotometry for Cr(VI) analysis, and potentiometry for pH determination. EK was run at 1 V/cm with no external constraints on current intensity. The EK experiment reached an extraction of 72% of the total leachable Cr(VI) after only 10 days of treatment and 84% after 20 days. Material texture, composition, and pH remained similar. These results indicate that EK presents a potential solution for extracting leachable Cr(VI) from COPR sites. The impounded COPR material appeared to be heterogeneous in composition at all scales, from field to lab sample, adding to the challenge of in-situ treatment.     

Encapsulation of Salmon Peptides in Marine Liposomes: Physico-Chemical Properties,Antiradical Activities and Biocompatibility Assays

Salmon byproducts (Salmo salar) generated by the food chain represent a source of long-chain polyunsaturated fatty acids (eicosapentaenoic acid (EPA): 20:5n-3; docosahexaenoic acid (DHA): 22:6n-3) and peptides that can be used as supplements in food for nutraceutical or health applications, such as in the prevention of certain pathologies (e.g., Alzheimer’s and cardiovascular diseases). The extraction of polar lipids naturally rich in PUFAs by enzymatic processes without organic solvent (controlled by pH-Stat method), coupled with the production of 1 kDa salmon peptides by membrane filtration, allowed the formulation of nanocarriers. The physicochemical properties of the nanoliposomes (size ranging from 120 to 140 nm, PDI of 0.27, zeta potential between −32 and −46 mV and encapsulation efficiency) were measured, and the bioactivity of salmon hydrolysate peptides was assessed (antioxidant and antiradical activity: ABTS, ORAC, DPPH; iron metal chelation). Salmon peptides exhibited good angiotensin-conversion-enzyme (ACE) inhibition activity, with an IC₅₀ value of 413.43 ± 13.12 µg/mL. Cytotoxicity, metabolic activity and proliferation experiments demonstrated the harmlessness of the nanostructures in these experimental conditions.     

Can female preference drive intraspecific diversity dynamics in brown trout (Salmo trutta,L.)?

Intraspecific diversity can be strongly impacted by the dynamics of reproductive isolation during secondary contacts. The high levels of hybridisation and introgression between Atlantic and Mediterranean lineages in contemporary populations of brown trout in the Northern part of the French Alps are a good case in point. After a long period of allopatry, which one assumes has facilitated their divergent phenotypic and genetic evolution, man has removed a geographical reproductive barrier via stocking the Atlantic lineage in the Mediterranean area, thereby potentially enabling gene flow between native and non native populations. We investigate how much a prezygotic reproductive behaviour, that is female preference for male phenotype, can influence hybridisation in natural environments, using subaquatic video recording of reproduction. Our statistical model indicates that female preference appears to be largely heterogamous: females tend to select dissimilar males with respect to their own phenotype; thus, rather than acting as a barrier to gene flow, female preference is favouring gene flow between lineages that have been artificially placed in sympatry. This finding based on observational data is in agreement with previously reported genetic data, high levels of hybridisation between the lineages. We suggest that a knowledge of reproductive behaviour in natural environments is an essential tool for biodiversity managers to assess the potential risks associated with the introduction into recipient populations of non‐native lineage fish at the intraspecific level.     

Malaria in an eastern screech owl (Otus asio)

Owls are frequent carriers of blood parasites but clinical malaria infections are rare. Various stages of Plasmodium subpraecox were seen in 90% of the erythrocytes of an Eastern screech owl (Otus asio) showing symptoms consistent with malaria 1 wk after admission for traumatic injuries. An additional unidentified blood parasite, either a Plasmodium or a Haemoproteus spp. was found in small numbers of red blood cells on blood films examined at admission and at day 7 postadmission. Combined infestation, trauma-induced stress, and iatrogenic corticosteroid administration are possible factors that could have induced disease. Oral treatment with mefloquine at 30 mg/kg, repeated after 12, 24, and 48 hr, proved successful in eliminating both organisms and signs of clinical disease.