Radical-scavenging activity of extracts from Cordia verbenacea DC obtained by different methods

The possibility of using the leaves of Cordia verbenacea as a new source of natural antioxidant compounds was investigated. In the present work, extracts from C. verbenacea were obtained using different extraction methods: supercritical fluid extraction (SFE), Soxhlet (SE), hydrodistillation and maceration, with the objective to evaluate the methods in terms of yield and antioxidant potential. The high-pressure technique was applied using pure CO₂ and CO₂ with co-solvent at different temperatures and pressures (30, 40 and 50 °C and 100, 200, and 300 bar). Organic solvents with different polarities were used to obtain extracts by low-pressure extraction processes. The extracts were evaluated according to their antioxidant activity using total phenolic content, scavenging abilities on DPPH radical, total antioxidant activities (ABTS^•+), superoxide anion radical-scavenging (O₂^•) and protection against lipid peroxidation in vitro (LPO). Ethyl acetate fraction obtained by maceration and extract isolated by SE using 25% aqueous mixture of ethanol possessed the highest scavenger activity against DPPH radical (IC₅₀ = 9.2 ± 0.4 μg/ml, IC₅₀ = 27.4 ± 0.1 μg/ml, respectively). The SFE with 8% ethanol as a co-solvent produced extracts with distinguished increase in the antioxidant activity. The Soxhlet extract with ethyl acetate exhibited a strong reduction of lipid peroxidation (IC₅₀ = 209 ± 3 μg/ml) value comparable to the standard rutin (IC₅₀ = 203 ± 2 μg/ml). The results indicate that extracts of C. verbenacea have important potential as a source of bioactive compounds with antioxidant activity.     

Assessment of Brazilian consumers' perception about the presence of stabilisers in UHT milk: A study using virtual focus groups

Several countries use stabilisers in the product to avoid undesirable alterations, such as aggregation/gelation of proteins after thermal processing of UHT milk. Brazilian consumers' perception of these additives was investigated using virtual focus groups. Several relevant factors to the decision of consumers were elicited. The results show that most consumers do not have the habit of reading the UHT milk label and demonstrate a lack of knowledge about using stabilisers in UHT milk, even confusing it with preservatives. It is noted that the dairy sector must improve its communication strategies for UHT milk consumers.     

Proteomic characterisation of subclover seed storage proteins during germination

BACKGROUND: Early seedling development is a critical step in the establishment of subclover (Trifolium subterraneum), an economically important and widespread pasture legume. In this study the seed storage proteome of this non‐model species was characterised in mature dry seeds and during imbibition by using two‐dimensional electrophoresis coupled with tandem mass spectrometry. RESULTS: The phenol‐extracted proteome of subclover dry seeds consisted of 97 polypeptide spots displayed within a window of pI 3–10 and molecular mass 10–150 kDa. De novo sequencing coupled with MS BLAST search enabled the confident identification of 61 proteins, which corresponded to 59 7S vicilin‐ and two 11S legumin‐type globulins. The experimental mobility of vicilin isoforms along with peptide mapping indicated that low‐molecular‐mass polypeptides might account for the post‐translational proteolysis of small vicilin subunits according to the model described for those of pea. Analysis of quantitative changes in the seed storage proteome upon imbibition showed that vicilin catabolism according to a site‐specific process was favoured during early seedling growth in T. subterraneum. CONCLUSION: The establishment of a seed proteome map for T. subterraneum pointed to vicilins as dominant proteins in mature seeds whose catabolism features during early seedling growth may be of relevance under environmental conditions. Copyright © 2009 Society of Chemical Industry     

Hydraulic and Biological Aspects of Fish Passes for Atlantic Salmon

This paper describes a series of novel experiments testing the relative efficiencies in passing juvenile salmon (parr) through a range of model fish passes incorporating devices such as vertical slots, orifices, weirs, and combinations of all three. The hydraulic parameters—head loss, velocity patterns, and turbulence structure—were measured under each set of test conditions. A significantly higher proportion of fish moved through submerged orifices and vertical slots than through overflow weirs for any given flow rate, velocity, and head loss. The orifice and vertical slot efficiencies were directly correlated to the velocities at their entrances. To reach the tested devices, salmon parr tended to remain near the bottom of the flume and followed paths providing them with low velocities and cover along the sides of the test arena. The movements of salmon approaching entrances were consistent with energy-conserving strategies. The paper presents a tentative approach for computing energy expenditure for a range of fish pass devices.     

有助于无线探头测量感应式电源的低功耗电压-频率转换器

为执行长期监视任务的便携式遥测系统供电．向人们提出了有趣的设计挑战。电池不适合于某些关键性应用，且在这些环境中，设计人员一般用无线感应链路来传输功率与数据。感应链路由一个驱动固定初级线圈的射频发射器与一个为便携式装置提供电源的松耦合次级线圈组成。对设计工程师来说．测量发射功率相当重要．因为它会限制设计人员可包含至便携式装置中的电路数量。但不幸的是，传统测试设备不适合执行该任务．     

Environmental Factors and Beta2‐Adrenergic Receptor Polymorphism: Influence on the Energy Expenditure and Nutritional Status of Obese Women

Our aim was to evaluate the influence of the Gln27Glu polymorphism of the β₂‐adrenergic receptor (ADRβ₂) gene, fat intake and physical activity on the energy expenditure (EE) and nutritional status of obese women. Sixty obese women (30–46 years) participated in the study and were assigned to three groups depending on the genotypes: Gln27Gln, Gln27Glu and Glu27Glu. At baseline and after nutritional intervention, the anthropometric and body composition (bioelectrical impedance), dietary, EE (indirect calorimetry) and biochemical variables were measured. All women received a high‐fat test meal to determine the postprandial EE (short‐term) and an energy‐restricted diet for 10 weeks (long term). The frequencies of Gln27Gln, Gln27Glu and Glu27Glu were 36.67, 40.0 and 23.33 %, respectively. Anthropometric and biochemical variables and EE did not differ between groups, although women who had no polymorphism demonstrated decreased carbohydrate oxidation. On the other hand, the Glu27Glu genotype showed a positive relation with EE in physical activity and fat oxidation. The environmental factors and Gln27Glu polymorphism did not influence the nutritional status and EE of obese women, but physical activity in obese women with the polymorphism in the ADRβ₂ gene can promote fat oxidation. The results suggest that encouraging the practice of physical exercise is important considering the high frequency of this polymorphism in obese subjects.     

Salted and fermented fish processes evaluation

Fish curing by salting and fermentation is the result of the action of certain enzymes over fresh fish. This study aimed to evaluate and compare three technological processing methods (A, B, C). Coliforms, Escherichia coli , Enterococcus spp ., coagulase-positive Staphylococcus , Salmonella spp., total volatile base (TVB), pH, water activity (Wa), sodium chloride and biogenic amines were evaluated. A significant difference in histamine production ( P  < 0.05) was observed. Escherichia spp ., Klebsiella spp , Proteus spp ., Shigella spp., Citrobacter spp. and Pseudomonas spp. were isolated . Sodium chloride content varied between 15.65 and 18.87% and no significant difference was observed ( P  > 0.05). Wa and pH showed significant differences ( P  < 0.05), with values between 0.71 and 0.75, and 5.54 and 5.93. TVB values varied between 15.1 and 62.1 mg N 100 g⁻¹, showing significant differences ( P  < 0.05) as well. Worrying levels of histamine were found. Processing method A was found to be the most appropriate for the production of this kind of fish.     

Processing of phosphocasein dispersions by dynamic high pressure: Effects on the dispersion physico-chemical characteristics and the binding of α-tocopherol acetate to casein micelles

Dispersions of phosphocaseins (PCs) containing (w/w) 2.5% proteins at pH 6.7 were processed using a ~ 15 L/h homogeniser with a high-pressure valve immediately followed by cooling devices. The effect of dynamic high-pressure (or ultra-high pressure homogenisation, UHPH) at 100–300 MPa and two initial temperatures (T_in = 14 °C or 34 °C) was investigated on (i) casein micelle size distributions, (ii) the turbidity and viscosity of PC dispersions, and (iii) the binding efficiency of α-tocopherol acetate (α-TA) to casein micelles (α-TA:PC molar ratio ~ 1:1). A significant and gradual decrease of casein micelle sizes was observed after UHPH up to 300 MPa at T_in = 14 °C. The decrease in micelle sizes was less extensive after UHPH at T_in = 34 °C. Notably, the binding efficiency of α-TA significantly (p < 0.001) increased after processing, suggesting combined effects of temperature and dynamic high-pressure.

Industrial relevance

Industrial operators in food, cosmetic and pharmaceutical areas are currently interested in developing encapsulating systems to delivery bioactive compounds, generally hydrophobic, unstable and sensitive to light, temperature or/and oxygen. The present study suggests that processing of casein micelle dispersions by dynamic high pressure at ≥ 200 MPa could modify casein micelle organisation with an enhancement of the binding of hydrophobic ligand (α-tocopherol acetate) to the newly UHPH-formed neo-micelles. Here is a potential application for UHPH, a physical technology that offers the added advantage of notably reducing the microbial load of processed samples.     

Mapping the fluorophilicity of a hydrophobic pocket: synthesis and biological evaluation of tricyclic thrombin inhibitors directing fluorinated alkyl groups into the p pocket

In the completion of our fluorine scan of tricyclic inhibitors to map the fluorophilicity/fluorophobicity of the thrombin active site, a series of 11 new ligands featuring alkyl, alkenyl, and fluoroalkyl groups was prepared to explore fluorine effects on binding into the hydrophobic proximal (P) pocket, lined by Tyr 60A and Trp 60D, His 57, and Leu 99. The synthesis of the tricyclic scaffolds was based on the 1,3-dipolar cycloaddition of azomethine ylides, derived from L-proline and 4-bromobenzaldehyde, with N-(4-fluorobenzyl)maleimide. Introduction of alkyl, alkenyl, and partially fluorinated alkyl residues was achieved upon substitution of a sulfonyl group by mixed Mg/Zn organometallics followed by oxidation/deoxyfluorination, as well as oxidation/reduction/deoxyfluorination sequences. In contrast, the incorporation of perfluoroalkyl groups required a stereoselective nucleophilic addition reaction at the "upper" carbonyl group of the tricycles, thereby yielding scaffolds with an additional OH, F, or OMe group, respectively. All newly prepared inhibitors showed potent biological activity, with inhibitory constants (K(i) values) in the range of 0.008-0.163 microM. The X-ray crystal structure of a protein-ligand complex revealed the exact positioning of a difluoromethyl substituent in the tight P pocket. Fluorophilic characteristics are attributed to this hydrophobic pocket, although the potency of the inhibitors was found to be modulated by steric rather than electronic factors.