Development of new active packaging films coated with natural phenolic compounds to improve the oxidative stability of beef

The aim is to develop active packaging films containing natural antioxidants and to evaluate their capacity to enhance the oxidative stability of beef during refrigeration. The antioxidant activity of a natural extract obtained from a brewery residual waste was evaluated and compared with that of a commercial rosemary extract and two synthetic antioxidants (BHT and propyl gallate). Different concentrations of each antioxidant were also added directly to beef samples, resulting in a reduction in lipid oxidation of up to 70–80% relative to the control. Active antioxidant films coated with PVPP-WS extract reduced lipid oxidation by up to 80%, relative to the control, during cold storage. The use of active packaging films containing natural extracts could improve the oxidative stability of meat products and should therefore be of great interest in the food industry.     

Assessment of nutritional compounds and antinutritional factors in pea (Pisum sativum) seeds

The nutrient and antinutritional factor content of 18 pea lines was studied. The following levels were found: non‐protein nitrogen 5.2–10.2 g kg^?1 DM, protein nitrogen 35.3–42.4 g kg^?1 DM, lysine 50.7–76.3 g kg^?1 protein DM, histidine 17.8–24.8 g kg^?1 protein DM, tyrosine 22.6–30.0 g kg^?1 protein DM, protein 25.9–31.9% DM, in vitro protein digestibility 89.3–95.6%, vitamin B₁ 5.9–10.3 mg kg^?1 DM, vitamin B₂ 1.1–3.7 mg kg^?1 DM, sucrose 11.6–25.4 g kg^?1 DM, raffinose 4.1–10.3 g kg^?1 DM, stachyose 10.7–26.7 g kg^?1 DM, verbascose 0.0–26.7 g kg^?1 DM, total α‐galactosides 22.6–63.4 g kg^?1 DM, trypsin inhibitor activity 0.8–8.4 TIU mg^?1 DM, inositol hexaphosphate 2.3–6.5 g kg^?1 DM, inositol pentaphosphate 0.1–1.8 g kg^?1 DM and total inositol phosphates 2.8–7.1 g kg^?1 DM. Peas with yellow cotyledons had the highest trypsin inhibitor activities, those with light green cotyledons had the highest lysine contents, and those with dark green cotyledons were the richest in vitamins B₁ and B₂. Peas with brown testae had the lowest verbascose and sucrose contents, while they were the richest in inositol hexaphosphate. Smaller peas were characterised by the highest protein nitrogen contents as well as the highest contents of vitamins B₁ and B₂, verbascose and inositol pentaphosphate. Peas of medium size showed the lowest verbascose, α‐galactoside and vitamin B₂ contents. Bigger peas showed the lowest inositol pentaphosphate contents. © 2003 Society of Chemical Industry     

A fast and reliable procedure to determine the copolymer composition by GPC‐IR: Application to ethylene/propylene copolymers and comparison with 13C NMR

Copolymer properties depend on several parameters and one of the most important is its composition. Typically, this composition is determined by ¹³C nuclear magnetic resonance (¹³C NMR) analysis, which requires a long acquisition time and a fine adjustment of parameters to obtain the desired resolution. In this article, a method to determine the comonomer content of polymers based on the analysis from gel permeation chromatography (GPC) with an infrared (IR) detector is described. This GPC‐IR method is faster than NMR and can be carried out routinely during the GPC analysis. Three sets of ethylene/propylene copolymers synthesized using metallocene and Ziegler–Natta catalyst over a wide composition range. Linear and second order polynomial equations were checked for the relation between the ethylene percent and the IR CH₃/CH ratio. Average deviation between GPC‐IR and NMR composition values was about 1% and allow conclude that this technique can be considered to be a goodalternative. POLYM. ENG. SCI., 2011. © 2010 Society of Plastics Engineers     

Monosaccharides and analogues from simple achiral unsaturated compounds

We present herein a selection of ingenious methods that have been developed to convert inexpensive furan, pyrrole and unsaturated hydrocarbons into enantiomerically enriched monosaccharides and analogues of biological interest.     

Characterization of ethylene‐propylene copolymers with high‐temperature gradient adsorption liquid chromatography and CRYSTAF

Blends of linear polyethylene (PE) and isotactic polypropylene (iPP) with different average molar masses and a series of ethylene‐propylene (EP) copolymers with different chemical composition as well as blends of PE, Ipp, and EP copolymers were separated using a carbon‐column packing (Hypercarb®) and gradients of 1‐decanol or 2‐ethyl‐1‐hexanol → 1,2,4‐trichlorobenzene (TCB). The separation is based on full adsorption of linear PE on the carbon sorbent at temperature 160°C. However, iPP is not adsorbed and elutes in size exclusion mode. The random EP copolymers have been adsorbed in the column packing and separated according to their average chemical composition after application of the gradient starting with alcohol and ending with pure TCB. The elution volumes of the copolymers depended linearly on the average concentration of ethylene in the copolymers. The HPLC elution profiles were correlated with the CRYSTAF elution profiles. In contrast to CRYSTAF, fully amorphous polyolefin samples were separated with the high‐temperature adsorption liquid chromatography. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Anthocyanin fingerprint of grapes: environmental and genetic variations

The anthocyanin content and fingerprint of four different Vitis vinifera L. varieties (Cabernet Sauvignon, Merlot, Syrah and Monastrell), the last grown in two different locations, were studied during three growing seasons to determine how seasonal conditions and location affect the content of berry anthocyanins and their relative percentages. Important differences in the content of anthocyanins were detected among varieties—Monastrell grapes from one of the locations presenting the highest anthocyanin content—when expressed as µg g^?1 of skin. However, due to the large berry size of Monastrell grapes, when the results were expressed as mg kg^?1 of berry, Cabernet Sauvignon and Syrah grapes presented the highest concentration. Significant differences were found as regards growing season, the concentration of anthocyanins being lowest in 2003, the warmest year. As regards the relative percentage of the different anthocyanins, substantial differences were found between varieties, but again, the results were also influenced by the year under study. When the percentages of anthocyanins were used as variables in a discriminant analysis, a 100% correct classification of the four different varieties was obtained. Moreover, to check the suitability of this tool for classifying varieties, data referring to the anthocyanin percentages of the four varieties grown in very different agroecological conditions and at different ripening stages were tested with the model we have built, 89% of correct classification being achieved. Copyright © 2006 Society of Chemical Industry     

Biomonitoring of urinary metals in a population living in the vicinity of industrial sources: a comparison with the general population of Andalusia, Spain

The Ria of Huelva (south-west Spain) is one of the most polluted fluvial-estuarine systems in the world. Industrial activity delivers huge amounts of pollutants to the local environment, particularly heavy metals and arsenic. Here we aimed to determine urinary levels of As, Cd, Cr, Cu and Ni in a representative sample (n=857) of adults living in the Ria of Huelva. Levels were compared to those from a representative sample of 861 adults of the general urban population of Andalusia (southern Spain) and multiple regression models were developed to identify individual factors associated with urinary levels of these elements. Arsenic levels were significantly higher in the Ria of Huelva as compared to other Andalusian cities, whereas Cd and Ni levels were significantly lower. Despite these differences, levels in both groups were similar to the reference values reported in previous studies for general population. Age, gender, diet and lifestyle were the major factors contributing to the interindividual variation in urinary metals. In conclusion, despite living in a highly polluted area, the population of the Ria of Huelva failed to show higher urinary levels of the studied metals as compared to a reference urban population of the same region.     

Hydrogenase-coated carbon nanotubes for efficient H2 oxidation

Multiwalled carbon nanotubes grown on gold electrodes manufactured by microtechnology techniques have been used as a platform for oriented and stable immobilization of a Ni-Fe hydrogenase. Microscopic and electrochemical characterization of the system are presented. High-density currents due to H2 oxidation electrocatalysis, stable for over a month under continuous operational conditions, were measured. The functional properties of this nanostructured hydrogenase electrode are suitable for hydrogen biosensing and biofuel applications.     

A voltammetric electronic tongue as tool for water quality monitoring in wastewater treatment plants

The use of a voltammetric electronic tongue as tool for the prediction of concentration levels of certain water quality parameters from influent and effluent wastewater from a Submerged Anaerobic Membrane Bioreactor pilot plant applied to domestic wastewater treatment is proposed here. The electronic tongue consists of a set of noble (Au, Pt, Rh, Ir, and Ag) and non-noble (Ni, Co and Cu) electrodes that were housed inside a stainless steel cylinder which was used as the body of the electronic tongue system. As a previous step an electrochemical study of the response of the ions sulphate, orthophosphate, acetate, bicarbonate and ammonium was carried out in water using the electrodes contained in the electronic tongue. The second part of the work was devoted to the application of the electronic tongue to the characterization of the influent and effluent waters from the wastewater treatment plant. Partial Least Squares analysis was used to obtain a correlation between the data from the tongue and the pollution parameters measured in the laboratory such as soluble chemical oxygen demand (CODs), soluble biological oxygen demand (BODs), ammonia (NH₄-N), orthophosphate (PO₄-P), Sulphate (SO₄-S), acetic acid (HAC) and alkalinity (Alk). A total of 28 and 11 samples were used in the training and the validation steps, respectively, for both influent and effluent water samples. The electronic tongue showed relatively good predictive power for the determination of BOD, COD, NH₄-N, PO₄-P, SO₄-S, and Alk.