Unprecedented Mo3S4 cluster-catalyzed radical C-C cross-coupling reactions of aryl alkynes and acrylates.

A new method for the generation of benzyl radicals from terminal aromatic alkynes has been developed, which allows the direct cross coupling with acrylate derivatives. Our additive-free protocol employs air-stable diamino Mo3S4 cubane-type cluster catalysts in the presence of hydrogen. A sulfur-centered cluster catalysis mechanism for benzyl radical formation is proposed based on catalytic and stoichiometric experiments. The process starts with the cluster hydrogen activation to form a bis(hydrosulfido) [Mo3(µ3-S)(µ-S)(µ-SH)2Cl3(dmen)3]+ intermediate. The reaction of various aromatic terminal alkynes containing different functionalities with a series of acrylates affords the corresponding Giese-type radical addition products.

Spin-Crossing in the (Z)-Selective Alkyne Semihydrogenation Mechanism Catalyzed by Mo3S4 Clusters: A Density Functional Theory Exploration.

Semihydrogenation of internal alkynes catalyzed by the air-stable imidazolyl amino [Mo3S4Cl3(ImNH2)3]+ cluster selectively affords the (Z)-alkene under soft conditions in excellent yields. Experimental results suggest a sulfur-based mechanism with the formation of a dithiolene adduct through interaction of the alkyne with the bridging sulfur atoms. However, computational studies indicate that this mechanism is unable to explain the experimental outcome: mild reaction conditions, excellent selectivity toward the (Z)-isomer, and complete deuteration of the vinylic positions in the presence of CD3OD and CH3OD. An alternative mechanism that explains the experimental results is proposed. The reaction begins with the hydrogenation of two of the Mo3(µ3-S)(µ-S)3 bridging sulfurs to yield a bis(hydrosulfide) intermediate that performs two sequential hydrogen atom transfers (HAT) from the S-H groups to the alkyne. The first HAT occurs with a spin change from singlet to triplet. After the second HAT, the singlet state is recovered. Although the dithiolene adduct is more stable than the hydrosulfide species, the large energy required for the subsequent H2 addition makes the system evolve via the second alternative pathway to selectively render the (Z)-alkene with a lower overall activation barrier.

Effect of fermented soy beverage in aged female mice model.

Soy beverage is a rich source of phytoestrogens isoflavones, with potential benefits on health. The effect of those compounds depends greatly on their bacterial metabolization into their aglycone forms. This study evaluated the health effects of two soy beverages, non-fermented (SB) and fermented with Bifidobacterium pseudocatenulatum INIA P815 (FSB), in acyclic and cyclic C57BL/6J aged female mice as a model of menopause and premenopause, respectively. SB and FSB treatments were administrated for 36 days and, subsequently, body weight, lipid and inflammatory profile and fertility were analyzed and compared. In addition, hepatic gene expression and faecal microbiota composition were also assessed. After fermentation, FSB presented a high content in the aglycones daidzein and genistein and a higher antioxidant activity. FSB treated cyclic mice showed a significant increase in the number of retrieved oocytes and zigotes. Differences in serum lipids were observed in triglycerides, which were lower in FSB than in SB groups. None of the treatments influenced the inflammatory profile or caused a dramatic change in the intestinal microbiota profile or hepatic gene expression in any of the groups. Our data showed that FSB provided greater health benefits than SB in lipid profile and fertility in cyclic mice. These beneficial effects could be attributed to the fermentation process, which produces more bioavailable and bioactive compounds, achieving a greater impact on health.

Base-Free Catalytic Hydrogen Production from Formic Acid Mediated by a Cubane-Type Mo3S4 Cluster Hydride.

Formic acid (FA) dehydrogenation is an attractive process in the implementation of a hydrogen economy. To make this process greener and less costly, the interest nowadays is moving toward non-noble metal catalysts and additive-free protocols. Efficient protocols using earth abundant first row transition metals, mostly iron, have been developed, but other metals, such as molybdenum, remain practically unexplored. Herein, we present the transformation of FA to form H2 and CO2 through a cluster catalysis mechanism mediated by a cuboidal [Mo3S4H3(dmpe)3]+ hydride cluster in the absence of base or any other additive. Our catalyst has proved to be more active and selective than the other molybdenum compounds reported to date for this purpose. Kinetic studies, reaction monitoring, and isolation of the [Mo3S4(OCHO)3(dmpe)3]+ formate reaction intermediate, in combination with DFT calculations, have allowed us to formulate an unambiguous mechanism of FA dehydrogenation. Kinetic studies indicate that the reaction at temperatures up to 60 °C ends at the triformate complex and occurs in a single kinetic step, which can be interpreted in terms of statistical kinetics at the three metal centers. The process starts with the formation of a dihydrogen-bonded species with Mo-H···HOOCH bonds, detected by NMR techniques, followed by hydrogen release and formate coordination. Whereas this process is favored at temperatures up to 60 °C, the subsequent ß-hydride elimination that allows for the CO2 release and closes the catalytic cycle is only completed at higher temperatures. The cycle also operates starting from the [Mo3S4(OCHO)3(dmpe)3]+ formate intermediate, again with preservation of the cluster integrity, which adds our proposal to the list of the infrequent cluster catalysis reaction mechanisms.

Tug-of-War Driven by the Structure of Carboxylic Acids: Tuning the Size, Morphology, and Photocatalytic Activity of α-Ag2WO4.

Size and morphology control during the synthesis of materials requires a molecular-level understanding of how the addition of surface ligands regulates nucleation and growth. In this work, this control is achieved by using three carboxylic acids (tartaric, benzoic, and citric) during sonochemical syntheses. The presence of carboxylic acids affects the kinetics of the nucleation process, alters the growth rate, and governs the size and morphology. Samples synthesized with citric acid revealed excellent photocatalytic activity for the degradation process of Rhodamine B, and recyclability experiments demonstrate that it retains 91% of its photocatalytic activity after four recycles. Scavenger experiments indicate that both the hydroxyl radical and the hole are key species for the success of the transformation. A reaction pathway is proposed that involves a series of dissolution-hydration-dehydration and precipitation processes, mediated by the complexation of Ag+. We believe these studies contribute to a fundamental understanding of the crystallization process and provide guidance as to how carboxylic acids can influence the synthesis of materials with controlled size and morphology, which is promising for multiple other scientific fields, such as sensor and catalysis fields.

Disclosing the Biocide Activity of α-Ag2-2xCuxWO4 (0 ≤ x ≤ 0.16) Solid Solutions.

In this work, α-Ag2-2xCuxWO4 (0 ≤ x ≤ 0.16) solid solutions with enhanced antibacterial (against methicillin-resistant Staphylococcus aureus) and antifungal (against Candida albicans) activities are reported. A plethora of techniques (X-ray diffraction with Rietveld refinements, inductively coupled plasma atomic emission spectrometry, micro-Raman spectroscopy, attenuated total reflectance-Fourier transform infrared spectroscopy, field emission scanning electron microscopy, ultraviolet-visible spectroscopy, photoluminescence emissions, and X-ray photoelectron spectroscopy) were employed to characterize the as-synthetized samples and determine the local coordination geometry of Cu2+ cations at the orthorhombic lattice. To find a correlation between morphology and biocide activity, the experimental results were sustained by first-principles calculations at the density functional theory level to decipher the cluster coordinations and electronic properties of the exposed surfaces. Based on the analysis of the under-coordinated Ag and Cu clusters at the (010) and (101) exposed surfaces, we propose a mechanism to explain the biocide activity of these solid solutions.

Essential Oils from Residual Foliage of Forest Tree and Shrub Species: Yield and Antioxidant Capacity.

Increasing applications and markets for essential oils could bring new opportunities for cost-effective and sustainable management of unused forestry biomass; however, better knowledge of the production and application of such essential oils is necessary. The objective of this work is to contribute to greater knowledge of the essential oil production on a pilot scale from foliage biomass of wild shrubs and tree residues produced in some forestry enhancement operations and to study their antioxidant capacity (ORAC-oxygen radical absorbance capacity). Fresh biomass (twigs) of seven species (E. globulus, E. nitens, P. pinaster, P. sylvestris, R. officinalis, C. ladanifer, and J. communis) was manually collected in Spain in two different periods and was ground at 30 mm and distilled in a 30 L stainless steel still with saturated steam. The essential oil components were identified by GC-MS and quantified by GC-FID, and their antioxidant activity was determined with the ORAC method. Promising results on essential oil yield were obtained with E. globulus, E. nitens, R. officinalis, and J. communis. All essential oils studied exhibited antioxidant capacity by the ORAC assay, particularly that from C. ladanifer. Moreover, oxygenated sesquiterpenes contents, one of the minor components of oils, were significantly correlated with ORAC values.

Autoclaved and Extruded Legumes as a Source of Bioactive Phytochemicals: A Review.

Legumes have been consumed since ancient times all over the world due to their easy cultivation and availability as a low-cost food. Nowadays, it is well known that pulses are also a good source of bioactive phytochemicals that play an important role in the health and well-being of humans. Pulses are mainly consumed after processing to soften cotyledons and to improve their nutritive and sensorial characteristics. However, processing affects not only their nutritive constituents, but also their bioactive compounds. The final content of phytochemicals depends on the pulse type and variety, the processing method and their parameters (mainly temperature and time), the food matrix structure and the chemical nature of each phytochemical. This review focuses on the changes produced in the bioactive-compound content of pulses processed by a traditional processing method like cooking (with or without pressure) or by an industrial processing technique like extrusion, which is widely used in the food industry to develop new food products with pulse flours as ingredients. In particular, the effect of processing methods on inositol phosphates, galactosides, protease inhibitors and phenolic-compound content is highlighted in order to ascertain their content in processed pulses or pulse-based products as a source of healthy phytochemicals.

Characterization of persistent Listeria monocytogenes strains from ten dry-cured ham processing facilities.

The majority of cases of listeriosis are associated with the consumption of contaminated food. Some strains of Listeria monocytogenes can persist over months or years in meat processing plants increasing the risk of product contamination. The presence of L. monocytogenes was examined in 10 dry-cured ham processing facilities. A total of 1801 samples were collected from environment and equipment, during processing (1095) and after cleaning and disinfection (706). These samples were taken from non-food contact (736) and food contact (1065) surfaces. In addition, 204 samples from ham surfaces were also analysed. Prevalence varied from 6% to 34% among facilities, and was higher during processing than after cleaning and disinfection (24.8% vs 11.0%) and from non-food than from food contact surfaces (22.6% vs 17.4%). L. monocytogenes serotype 1/2a was predominant (53.9%), followed by 1/2c (26.0%) and 1/2b (15.3%) and less frequently 4b (4.8%). A total of 142 different pulsotypes were registered. Potential persistent L.monocytogenes strains were isolated in 9 out the 10 facilities, with no more than 6 pulsotypes in a given plant. Two pulsotypes were common in different installations, detected before and after cleaning and disinfection, highlighting the importance of monitoring the presence of this pathogen in dry-cured ham processing environments.

Cooking and sensorial quality, nutritional composition and functional properties of cold-extruded rice/white bean gluten-free fettuccine fortified with whole carob fruit flour.

A different rice/white bean-based gluten-free fettuccine (rice 0-100%, bean 0-100%) fortified with 10% carob fruit has been developed. The proximate composition, total and resistant starch, and total, soluble and insoluble dietary fibre content as well as the cooking and sensorial quality of uncooked and cooked pasta were determined. All the novel gluten-free fettuccine forms showed good cooking quality (cooking loss < 10%) highlighting that those containing the carob fruit had better nutritional and healthy profiles than the commercial gluten-free rice pasta; they were low in fat (10-fold) and high in protein (on average 3.6-fold) with resistant starch (16%) and dietary fibres (2.4-fold). The cooking process increased (p < 0.05) the protein and total dietary fibre content but reduced the total and resistant starch. The addition of carob fruit increased the total dietary fibre content, thus improving the functional value of fettuccine. Considering the sensorial analysis, fettuccine produced with 40% bean and 10% carob could be well accepted by consumers and can be advised as a functional food.

Cooking Effect on the Bioactive Compounds, Texture, and Color Properties of Cold-Extruded Rice/Bean-Based Pasta Supplemented with Whole Carob Fruit.

Pasta is considered as the ideal vehicle for fortification; thus, different formulations of gluten-free pasta have been developed (rice 0-100%, bean 0-100%, and carob fruit 0% or 10%). In this article, the content of individual inositol phosphates, soluble sugars and α-galactosides, protease inhibitors, lectin, phenolic composition, color, and texture were determined in uncooked and cooked pasta. The highest total inositol phosphates and protease inhibitors contents were found in the samples with a higher bean percentage. After cooking, the content of total inositol phosphates ranged from 2.12 to 7.97 mg/g (phytic acid or inositol hexaphosphate (IP6) was the major isoform found); the protease inhibitor activities showed values up to 12.12 trypsin inhibitor (TIU)/mg and 16.62 chymotrypsin inhibitor (CIU)/mg, whereas the competitive enzyme-linked immunosorbent assay (ELISA) showed the elimination of lectins. Considering the different α-galactosides analyzed, their content was reduced up to 70% (p < 0.05) by the cooking process. The total phenols content was reduced around 17-48% after cooking. The cooked samples fortified with 10% carob fruit resulted in darker fettuccine with good firmness and hardness and higher antioxidant activity, sucrose, and total phenols content than the corresponding counterparts without this flour. All of the experimental fettuccine can be considered as functional and healthy pasta mainly due to their bioactive compound content, compared to the commercial rice pasta.

Bioactive Compounds, Antioxidant Activity, and Sensory Analysis of Rice-Based Extruded Snacks-Like Fortified with Bean and Carob Fruit Flours.

Generally, extruded gluten-free foods are mostly phytochemically deficient. In this study inositol phosphates, α-galactosides, lectins, protease inhibitors, and phenols, their antioxidant activity and sensorial analysis of some rice/bean/whole carob fruit flour blends were determined in unprocessed (controls) and extruded formulations. The fortification of rice-based extrudates with both legumes has a positive influence on both their bioactive compound content and their acceptability by consumers. The extruded formulations contained around twice as much (p < 0.05) total α-galactosides than their unprocessed counterparts. Extrusion significantly reduced the phytic acid content (10%) and significantly increased the less phosphorylated forms (16%-70%). After extrusion, the lectins and protease inhibitors were eliminated. The different phenolic compounds mostly increased (11%-36%), notably in the formulations with carob fruit. The antioxidant activity and the different groups of phenols showed a positive correlation in the extrudates. All the experimental extrudates had higher amounts of bioactive compounds than the commercial extruded rice. Considering the amount of phytochemicals determined in the novel gluten-free extrudates and the scores of sensorial analysis, formulations containing 20%-40% bean and 5% carob fruit could be adequate in promoting health-related functions, helping to increase pulse consumption, and allowing the food industry to satisfy consumers' requirement for functional foods.

Healthy novel gluten-free formulations based on beans, carob fruit and rice: Extrusion effect on organic acids, tocopherols, phenolic compounds and bioactivity.

Rice and legumes have great potential in the development of novel gluten-free snacks that are healthier than traditional snacks. Novel gluten-free extruded foods (composed of rice: 50-80%, beans: 20-40% and carob: 5-10%) were analysed and the extrusion effects regarding organic acids, tocopherols, phenolic compounds and bioactive properties were evaluated. The total concentration of organic acids was not significantly affected by extrusion, while tocopherols showed a significant reduction. Extrusion did not produce an increase of the total phenolic content. For the bioactivity assays, commercial extruded rice, carob and most of the extruded samples showed anti-proliferative activity, which was higher than in the non-extruded samples, while for the anti-inflammatory activity, the extrusion process did not show a significant effect. Regarding the antimicrobial activity, low potential was observed with extruded and non-extruded samples showing high values of MIC and MBC as the microorganisms tested were multi-resistant isolated clinical strains.

Efficient and Selective N-Methylation of Nitroarenes under Mild Reaction Conditions.

Herein, we report a straightforward protocol for the preparation of N,N-dimethylated amines from readily available nitro starting materials using formic acid as a renewable C1 source and silanes as reducing agents. This tandem process is efficiently accomplished in the presence of a cubane-type Mo3 PtS4 catalyst. For the preparation of the novel [Mo3 Pt(PPh3 )S4 Cl3 (dmen)3 ]+ (3+ ) (dmen: N,N'-dimethylethylenediamine) compound we have followed a [3+1] building block strategy starting from the trinuclear [Mo3 S4 Cl3 (dmen)3 ]+ (1+ ) and Pt(PPh3 )4 (2) complexes. The heterobimetallic 3+ cation preserves the main structural features of its 1+ cluster precursor. Interestingly, this catalytic protocol operates at room temperature with high chemoselectivity when the 3+ catalyst co-exists with its trinuclear 1+ precursor. N-heterocyclic arenes, double bonds, ketones, cyanides and ester functional groups are well retained after N-methylation of the corresponding functionalized nitroarenes. In addition, benzylic-type as well as aliphatic nitro compounds can also be methylated following this protocol.

Kinetics Aspects of the Reversible Assembly of Copper in Heterometallic Mo3CuS4 Clusters with 4,4'-Di-tert-butyl-2,2'-bipyridine.

Treatment of the triangular [Mo3S4Cl3(dbbpy)3]Cl cluster ([1]Cl) with CuCl produces a novel tetrametallic cuboidal cluster [Mo3(CuCl)S4Cl3(dbbpy)3][CuCl2] ([2][CuCl2]), whose crystal structure was determined by X-ray diffraction (dbbpy = 4,4'-di-tert-butyl-2,2'-bipyridine). This species, which contains two distinct types of Cu(I), is the first example of a diimine-functionalized heterometallic M3M'S4 cluster. Kinetics studies on both the formation of the cubane from the parent trinuclear cluster and its dissociation after treatment with halides, supported by NMR, electrospray ionization mass spectrometry, cyclic voltammetry, and density functional theory calculations, are provided. On the one hand, the results indicate that addition of Cu(I) to [1]+ is so fast that its kinetics can be monitored only by cryo-stopped flow at -85 °C. On the other hand, the release of the CuCl unit in [2]+ is also a fast process, which is unexpectedly assisted by the CuCl2- counteranion in a process triggered by halide (X-) anions. The whole set of results provide a detailed picture of the assembly-disassembly processes in this kind of cluster. Interconversion between trinuclear M3S4 clusters and their heterometallic M3M'S4 derivatives can be a fast process occurring readily under the conditions employed during reactivity and catalytic studies, so their occurrence is a possibility that must be taken into account in future studies.

In vitro anti-inflammatory activity of phenolic rich extracts from white and red common beans.

According to epidemiological evidence, diets rich in fruits and vegetables can reduce the incidence of several chronic diseases that share an inflammatory component. These protective effects are attributed, in part, to the occurrence of different antioxidant components, mainly phenolic compounds. Our aim was to characterise phenolic composition, and to determine antioxidant and anti-inflammatory activities of phenolic rich extracts obtained from two kinds of common beans, white kidney beans (WKB) and round purple beans (RPB). Phenolic acids were the predominant component in WKB extracts, whereas RPB extracts presented higher concentrations of phenolic compounds, mainly catechin derivatives, proanthocyanidins and catechin glucoside. In addition, RPB extracts showed higher antioxidant capacity and higher anti-inflammatory activity by the reduction of NO production and cytokine mRNA expression of LPS stimulated macrophages. These results suggest that common bean extracts may be used as a source of anti-inflammatory agents as well as a dietary complement for health promotion.

Storage temperature and UV-irradiation influence on the ergosterol content in edible mushrooms.

Ergosterol (5,7,22-ergostatrien-3ß-ol) and ergosteryl derivatives from different genera of edible mushrooms were separated and quantified by an isocratic reversed-phase high performance liquid chromatography (HPLC) method. The technique allowed a rapid separation of free ergosterol and two ergosteryl derivatives occurring in mushrooms. The ergosterol content varied considerably depending on the fungus. Thus, the species Agaricus bisporus and Hygrophorus marzuolus presented high quantities of ergosterol (6.4-6.8 mg/g, dry matter) followed by Pleurotus ostreatus, Calocybe gambosa, Lentinus edodes, and Boletus edulis (3.3-4.0mg/g). In contrast, other species, such as Cantharellus cibarius, Lactarius deliciosus and Craterellus cornucopioides, contained significantly lower ergosterol amounts (0.2-0.4 mg/g). Two ergosteryl derivatives were found in mushrooms and also the content depended on the fungus. The stability of ergosterol, in terms of the formation of ergosterol peroxide, was evaluated under different storage temperatures and UV radiation. The lower the temperature (-20°C) and the radiation time (10 min), the lower ergosterol oxidation was observed.

Novel isolation of water-soluble polysaccharides from the fruiting bodies of Pleurotus ostreatus mushrooms.

Novel water-soluble polysaccharides have been isolated from the fruiting bodies of the edible mushroom Pleurotus ostreatus. Three polysaccharide fractions were obtained by ethanol precipitation from cold water, hot water and hot aqueous NaOH extracts. The fractions were purified by size exclusion chromatography showing a unique carbohydrate occurring in each fraction: PC from the cold fraction, PH from the hot fraction and PB from the hot aqueous NaOH fraction. The analysis of the methylated alditol acetates and the NMR studies revealed that all the polysaccharides displayed a linear backbone. PC was formed by α-(1→3),(1→6)-linked galactopyranosyl residues whereas PH and PB consisted of glucose-linked units. PH was exclusively composed of glucopyranosyl units bound by α-(1→4) linkages whereas PB was a ß-linked glucan showing (1→3) and (1→6) glycosidic bonds. The analysis of molecular arrangement by complexation with Congo red showed that only the ß-linked polysaccharide (PB) displayed a triple helix conformation.

Strategies for the preparation and concentration of mushroom aromatic products.

Fungal aroma comprises at least seven chemical groups of volatile organic compounds, which are plain hydrocarbons, heterocycles, alcohols, phenols, acids and derivatives, carbonyls (aldehydes and ketones), and sulfur containing molecules. This aromatic blend provides the excellent sensory properties to produce and several strategies have been employed to create aromatic products having the aroma and taste of mushrooms and truffles. Nowadays, there are several procedures to obtain aroma concentrates. Among them, the simulation of mushroom aroma by the combination of the main substances responsible for the flavour could be an efficient strategy. Nevertheless, natural procedures are gaining more importance since the concentrate is not a synthetic product and the processes commonly involve the use of mushroom waste. In this field, the maceration with precursor molecules, such as linoleic acid, or different types of enzymes is commonly used in food industry. This article provides a wide view of the most common strategies to produce fungal aroma taking into account the main advantages and disadvantages they present. The article presents some promising patents on strategies for the preparation and concentration of mushroom aromatic products.

Use of modified atmosphere packaging to preserve mushroom quality during storage.

Mushrooms have attracted much attention due to their excellent nutritional and sensory properties. However, they are highly perishable and rapidly lose their organoleptic characteristics. Many methods have been employed for mushroom storage, such as packaging, blanching, canning, or freeze drying. Among them, modified atmosphere packaging (MAP) has been widely employed for preserving fresh mushrooms. MAP provides an affordable packaging system that partly avoids enzymatic browning, fermentation and other biochemical processes by maintaining a controlled gas atmosphere. Several factors, including optimum CO2 and O2 partial pressures, permeability, package material, thickness, or product weight, must be considered in order to design a suitable modified atmosphere package for mushrooms. Thus, different strategies are available to preserve mushroom quality after harvest. The article presents some promising patents on use of modified atmosphere packaging to preserve mushroom quality during storage.