Kinetics of the solvent-free hydrogenation of 2-methyl-3-butyn-2-ol over a structured Pd-based catalyst

The solvent-free selective hydrogenation of 2-methyl-3-butyn-2-ol (MBY) to 2-methyl-3-buten-2-ol (MBE) was studied over a Pd/ZnO structured catalyst and compared to its behavior in water-assisted conditions. The catalytic behavior was correlated with the surface properties of the catalysts which were characterized by X-ray diffraction and X-ray photoelectron spectroscopy. The catalyst showed high selectivity and stability with the performance being superior to that of the industrial Lindlar catalyst (50%). The addition of a sulphur-containing modifier in the reaction mixture was found to affect the activity and to hinder the over-hydrogenation reaction. The MBE yield of 97% was attained at MBY conversion >99%. The reuse of the catalyst showed that it deactivated by a 38% and that its selectivity slightly increased (0.5%) over 10 runs. The reaction kinetics was modeled using a Langmuir–Hinshelwood mechanism considering competitive adsorption for the organic species and dissociative adsorption for hydrogen. The kinetic experiments were planned and the results analyzed following a design of experiments (DOE) methodology. This approach led not only to a robust model that predicts the reaction rate in a wide range of reaction conditions but also to the determination of its kinetic parameters.     

Membrane Vesicles for Nanoencapsulated Sulforaphane Increased Their Anti-Inflammatory Role on an In Vitro Human Macrophage Model

At present, there is a growing interest in finding new non-toxic anti-inflammatory drugs to treat inflammation, which is a key pathology in the development of several diseases with considerable mortality. Sulforaphane (SFN), a bioactive compound derived from Brassica plants, was shown to be promising due to its anti-inflammatory properties and great potential, though its actual clinical use is limited due to its poor stability and bioavailability. In this sense, the use of nanocarriers could solve stability-related problems. In the current study, sulforaphane loaded into membrane vesicles derived from broccoli plants was studied to determine the anti-inflammatory potential in a human-macrophage-like in vitro cell model under both normal and inflammatory conditions. On the one hand, the release of SFN from membrane vesicles was modeled in vitro, and two release phases were stabilized, one faster and the other slower due to the interaction between SFN and membrane proteins, such as aquaporins. Furthermore, the anti-inflammatory action of sulforaphane-loaded membrane vesicles was demonstrated, as a decrease in interleukins crucial for the development of inflammation, such as TNF-α, IL-1β and IL-6, was observed. Furthermore, these results also showed that membrane vesicles by themselves had anti-inflammatory properties, opening the possibility of new lines of research to study these vesicles, not only as carriers but also as active compounds.     

Novel varieties of broccoli for optimal bioactive components under saline stress

BACKGROUND: Consumption of broccoli is increasing steadily worldwide because of the interest in its bioactive composition and nutritive value for health promotion. Novel broccoli cultivars to be established under current adverse conditions in production areas (aggressive environmental conditions and saline irrigation waters) need to maintain physical and nutritional quality for consumption and year‐round supply to the markets. The newly introduced cultivars ‘Naxos’ and ‘Parthenon’ have been selected as potential candidates to replace the currently underperforming ‘Nubia’ variety. We aimed to compare the physical and phytochemical quality (glucosinolates, hydroxycinnamic acids, flavonoids, vitamin C and minerals), as well as the in vitro antioxidant capacity of these three cultivars under conditions of environmental stress. RESULTS: ‘Parthenon’ showed equal productivity and nutritional composition to ‘Nubia’, whereas ‘Naxos’ presented in general the best results when compared to ‘Nubia’ and ‘Parthenon’. For phenolic compounds ‘Nubia’ presented the highest contents, although ‘Naxos’ seemed better adapted to saline stress conditions, as suggested by the lowest degree of variation in the contents of healthy phytochemicals, including phenolic compounds, when grown under such conditions. CONCLUSION: ‘Naxos’ broccoli performed best and is a suitable candidate to replace ‘Nubia’ for marketable, nutritive and phytochemical quality, especially in areas of production under adverse conditions as found in Mediterranean southeast Spain (semiarid climate with saline irrigation water). Copyright © 2011 Society of Chemical Industry     

Composition and antioxidant capacity of a novel beverage produced with green tea and minimally-processed byproducts of broccoli

Organic green tea, one of the most-consumed beverages worldwide, is rich in bioactive compounds (flavonols and flavanols) with healthy properties. Broccoli byproducts, consisting of leaves and stalks, are rich in bioactive compounds, including nitrogen–sulphur compounds (glucosinolates and isothiocyanates) and phenolics (chlorogenic and sinapic acid derivatives, and flavonoids), as well as essential nutrients (minerals and vitamins). They are of high interest as a source of health-promoting compounds, useful as ingredients for the development of functional foods. This work analyses minimally-processed broccoli byproducts as a source of bioactive ingredients to design novel beverages, using organic green tea as a food matrix. Green tea enriched with broccoli concentrates showed improved physical quality, phytochemical composition and antioxidant capacity. The functional quality of these novel beverages depends on the proportion of broccoli extracts added to the green tea. The results obtained in the present work should encourage the use of broccoli byproducts as ingredients in novel functional foods.

Industrial relevance

The industrial use of broccoli byproducts as an ingredient in the development of novel, functional foods may help to add value to the large amount of plant wastes generated in every cropping season, thus reducing their environmental impact. The objectives and aims of the EU producers, industry and stakeholders on the relationships between foods, nutrition and health, and therefore, the use of suitable ingredients from the agriculture to have impact on human health and the environment, with a sustainable use of natural resources are in agreement with this work, adding value to broccoli byproducts and encouraging the production of novel products and applications for nutritional and/or health claims under the EU Regulations (EC) No. 1924/2006 and 834/2007.     

Temporal variations of mineral character of acid-producing pyritic coastal sediments, Southeast Queensland, Australia

The lower Pimpama River catchment possesses many features of morphology, geology and landuse, typical for Southeast Queensland. Pimpama River and its main tributary Hotham Creek meander over a coastal plain which developed during the last several thousand years as a result of sea level fluctuations and changing fluvial and estuarine regimes which provided ideal conditions for the formation of sedimentary pyrite. A complex mixture of natural and human factors triggers and controls the oxidation and hydrolysis of this pyrite. The consequent production of sulfuric acid and leaching of metals from the pyrite-rich sediments represent main environmental issues of this coastal setting. This study aimed to determine the lithological character of the coastal unconsolidated sediments, and identify changes produced by acidity over a long period of time in a natural system and over a short period of time in a laboratory system. The mineral composition of the estuarine sediments of the coastal plain reflects the lithology of their source, the geological basement, and also the enhanced weathering rate due to acid production. The primary minerals present in the sediments consist of quartz and feldspars (primarily albite, K-feldspars to a lesser extent and minor anorthite) the product of physical weathering of bedrock material, mainly sandstone. Kaolinite is the dominant clay mineral and represents the product of intense leaching of feldspars promoted by acid conditions. Kaolinite is fairly ordered in structure in fresh and weathered bedrock and it becomes disordered in the estuarine sediments. Illite is mainly present in bedrock-related samples and the highest amounts are associated with muscovite. In the tidal sediments, illite is present to a lesser extent and is not found in the lower estuary. The distribution of mixed layers of smectite-illite is highly variable and their deposition is mainly controlled by the hydrodynamic conditions of the environment. Only low energy tidal settings favour the deposition of smectites. Pyrite is present at many sites and is always accompanied by oxidation products such as jarosite and gypsum. The laboratory experiment showed that in the short-term, changes induced by acid production mainly involved the: (1) decomposition of oxidation products such as gypsum and jarosite, (2) weathering of feldspars (mainly plagioclase), and (3) increased amount of kaolinite and possible increased structural disorder. These observations are of significance when considering wetlands as a method of remediating acid-producing areas by re-establishment of reducing conditions. Jarosite is quite widespread and can represent a source of acid over a short period of time in water-saturated, partially oxidized pyrite-rich sediments. The initial several months of a wetland establishment may, however, be dominated by secondary acid production and metal leaching from preexisting oxidation products like jarosite and natrojarosite.     

Modelling Cr(VI) removal by a combined carbon-activated sludge system

The combined carbon-activated sludge process has been proposed as an alternative to protect the biomass against toxic substances in wastewaters; however, the information about the effect of powdered-activated carbon (PAC) addition in activated sludge reactors for the treatment of wastewaters containing Cr(VI) is limited. The objectives of the present study were: (a) to evaluate the removal of hexavalent chromium by (i) activated sludge microorganisms in aerobic batch reactors, (ii) powdered-activated carbon, and (iii) the combined action of powdered-activated carbon and biomass; (b) to propose mathematical models that interpret the experimental results. Different Cr(VI) removal systems were tested: (S1) biomass (activated sludge), (S2) PAC, and (S3) the combined activated carbon-biomass system. A Monod-based mathematical model was used to describe the kinetics of Cr(VI) removal in the system S1. A first-order kinetics with respect to Cr(VI) and PAC respectively, was proposed to model the removal of Cr(VI) in the system S2. Cr(VI) removal in the combined carbon-biomass system (S3) was faster than both Cr(VI) removal using PAC or activated sludge individually. Results showed that the removal of Cr(VI) using the activated carbon-biomass system (S3) was adequately described by combining the kinetic equations proposed for the systems S1 and S2.     

Application of culture-dependent and culture-independent methods for the identification of Lactobacillus kefiranofaciens in microbial consortia present in kefir grains

The biological and technological characteristics of kefiran as well as its importance in grain integrity led us to analyze the microbial kefir grain consortium with focus on Lactobacillus kefiranofaciens. The presence of L. kefiranofaciens in the nine kefir grains studied was demonstrated by denaturing gradient gel electrophoresis. By culture dependent methods applying a methodology focused on the search of this species, 22 isolates with typical morphology were obtained and identified applying a combination of SDS-PAGE of whole cell proteins, (GTG)₅-PCR and sequence analysis of the housekeeping gene encoding the α-subunit of bacterial phenylalanyl-tRNA synthase (pheS). This polyphasic approach allowed the reliable identification of 11 L. kefiranofaciens, 5 Lactobacillus paracasei, 4 Lactobacillus kefiri and 2 Lactobacillus parakefiri isolates. Isolated L. kefiranofaciens strains produced polysaccharide in strain-dependent concentrations and EPS produced by them also differed in the degree of polymerization. The isolation and accurate identification of L. kefiranofaciens is relevant taking into account the important role of this microorganism in the grain ecosystem as well as its potential application as starter in food fermentations.     

Sensory, microbiological, physical and chemical properties of cuttlefish (Sepia officinalis) and broadtail shortfin squid (Illex coindetii) stored in ice

The objective of this study was to characterize whole raw cuttlefish (Sepia officinalis) and shortfin squid (Illex coindetii) during storage in ice through sensory, microbiological, chemical and physical analyses. The recently developed Quality Index Method (QIM) tables for these species were used for sensory analysis. Shelf-life of whole cuttlefish and shortfin squid were estimated as around 10 and 9 days, respectively, according to QIM, which is shorter than for most species, especially fish. The numbers of microorganisms found in cuttlefish and shortfin squid surfaces until rejection were lower than in fish, which suggest predominance of enzymatic (autolytic) degradation. H₂S-producing bacteria constituted a significant proportion of the spoilage flora. Physical analysis performed using the RT-Freshmeter and the Torrymeter showed these instruments can be applied to cuttlefish and shortfin squid, providing useful complementary information on the rates of change of electrical properties. Free tryptophan and VBN contents significantly changed during the first storage week indicating that low levels of these compounds could be used as indicators of fresh and high quality cuttlefish and broadtail shortfin squid. Urea can be useful as spoilage indicator for cuttlefish, as well as agmatine for broadtail shortfin squid. An overall look into data obtained shows, as expected, that spoilage of these cephalopod species can be considered a different phenomena when compared to fish and is not yet completely clarified.