Spray-dried encapsulation of chia essential oil (Salvia hispanica L.) in whey protein concentrate-polysaccharide matrices

Eight chia essential oil-in-water fresh emulsions (E) variations were prepared using biopolymers blends whey protein concentrate (WPC) with mesquite gum (MG) or gum Arabic (GA), core to wall material ratios (C_o:W_a) of 1:2 and 1:3, and total solids contents (TSC) of 30 and 40 wt%. All E variations displayed volume-weighted mean size (d_4,3) droplet sizes that fell within 2.32 and 3.35 μm and rates of droplet coalescence (k_C) of 10⁻⁸ s⁻¹. E variations were spray-dried and the resulting microcapsules (M) had d_4,3 falling within the range of 13.17–28.20 μm. The encapsulation efficiency (EE) was higher than 70% for all M, but those obtained from E with lower TSC and higher C_o:W_a displayed higher EE and lower surface oil, independently of M particle size. The reconstituted emulsions (RE) exhibited significantly higher d_4,3 and k_C values of the same magnitude as E variations.     

Stoichiometry Controlled,Single‐Crystalline Bi2Te3 Nanowires for Transport in the Basal Plane

Thermoelectric Bi₂Te₃ based bulk materials are widely used for solid‐state refrigeration and power‐generation at room temperature. For low‐dimensional and nanostructured thermoelectric materials an increase of the thermoelectric figure of merit ZT is predicted due to quantum confinement and phonon scattering at interfaces. Therefore, the fabrication of Bi₂Te₃ nanowires, thin films, and nanostructured bulk materials has become an important and active field of research. Stoichiometric Bi₂Te₃ nanowires with diameters of 50–80 nm and a length of 56 μm are grown by a potential‐pulsed electrochemical deposition in a nanostructured Al₂O₃ matrix. By transmission electron microscopy (TEM), dark‐field images together with electron diffraction reveal single‐crystalline wires, no grain boundaries can be detected. The stoichiometry control of the wires by high‐accuracy, quantitative enegy‐dispersive X‐ray spectroscopy (EDX) in the TEM instrument is of paramount importance for successfully implementing the growth technology. Combined electron diffraction and EDX spectroscopy in the TEM unambiguously prove the correct crystal structure and stoichiometry of the Bi₂Te₃ nanowires. X‐ray and electron diffraction reveal growth along the [110] and [210] directions and the c axis of the Bi₂Te₃ structure lies perpendicular to the wire axis. For the first time single crystalline, stoichiometric Bi₂Te₃ nanowires are grown that allow transport in the basal plane without being affected by grain boundaries.     

Wheat gluten fractions as wood adhesives—glutenins versus gliadins

Plant proteins, such as wheat gluten, constitute attractive raw materials for sustainable wood adhesives. In this study, alkaline water dispersions of the protein classes of wheat gluten, glutenin, and gliadin were used as adhesives to bond together wood substrates of beech. The aim of the study is to measure the tensile shear strength of the wood substrates to compare the adhesive performance of glutenin and gliadin and to investigate the influence of application method and penetration of the dispersions into the wood material. A sodium hydroxide solution (0.1M) was used as dispersing and denaturing agent. Dispersions with different protein concentrations and viscosities were used, employing wheat gluten dispersions as references. Two different application methods, a press temperature of 110°C and a press time of 15 min, were employed. The tensile shear strength and water resistance of the wood substrates were compared, using a slightly modified version of the European Standard EN 204. The bond lines of the substrates were examined by optical microscopy to study the penetration and bond‐line thickness. The results reveal that the adhesive properties of gliadin are inferior to that of both glutenin and wheat gluten, especially in terms of water resistance. However, the tensile shear strength and the water resistance of gliadin are significantly improved when over‐penetration of the protein into the wood material is avoided, rendering the adhesive performance of gliadin equal to that of glutenin and wheat gluten. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Polyethylene glycol‐sugar composites as shape stabilized phase change materials for thermal energy storage

Polyethylene glycol (PEG)‐sugar composites have been investigated as cost effective shape‐stabilized phase change materials for thermal energy storage. PEGs form internal hydrogen bonds stabilizing their chains at solid state. However low molecular weight PEGs are liquid due to short chains as high molecular weight PEGs have too little concentration of hydroxyl groups. Therefore, glucose, fructose, and lactose are used as hydrogen bond source in this study. Consequently it is found that sugars stabilized PEGs up to 90% PEG constitution in solid state except for 90%PEG10,000/10% fructose blend. Fourier transform‐infrared (FT‐IR) analysis revealed considerable interactions between PEGs. The maximum changes in the spectra were observed in the OH stretching region as band broadening due to increasing hydrogen bonding interactions. Differential scanning calorimetry (DSC) analysis are used to determine phase change temperatures and enthalpy of the shape‐stabilized composites that are slightly lower than those of PEG precursors due to the interference effect of sugar in crystallization process. The enthalpies of the blends are 89%, 95%, and 94% of expected from 90%PEG/10% glucose blends, 93%, 94%, and 93% of expected from 90% PEG/10% fructose blends, and 99%, 96%, and 96% of expected from 90% PEG/10% lactose blends respectively when PEGs with 1,000; 6,000; and 10,000 g/mol average molecular weights are used respectively. The diameter of the spherulitic crystals of PEGs decreases with the addition of any of sugar derivatives and spherulites of the composites turns to semi‐amorphous solid structures at temperatures above melting point of PEG precursor. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers     

Anti-inflammatory activity of methanolic extracts from edible mushrooms in LPS activated RAW 264.7 macrophages

Nowadays there is a great interest in the use of edible mushrooms as functional food since they are rich in bioactive compounds. Although their immunomostimulant activity has been largely demonstrated, their potential anti-inflammatory activity has been scarcely explored. We have investigated the anti-inflammatory activity of methanolic extracts from different edible mushrooms species: Agaricus bisporus, Boletus edulis, Cantherellus cibarius, Cratarellus cornucopioides, Lactarius deliciosus and Pleurotus ostreatus, in activated macrophages. The species that exhibited higher anti-inflammatory activities were A. bisporus, C. cibarius and L. deliciosus, inducing inhibition of NO production and iNOS, IL-1β and IL6 mRNAs expression in response to LPS stimulation. C. cornucopioides only induced inhibition of NO production and iNOS expression, and the other species did not present anti-inflammatory effects. Therefore, some edible mushrooms species have a potential anti-inflammatory capacity in vitro, suggesting that they could be regarded as a potential source of natural anti-inflammatory agents.     

Parental family food choice motives and children’s food intake

Children’s food intakes are important for their health and it is their parents that mainly decide what foods are available at home. The purpose of this study was to examine the relationships between parental family food choice motives (FFCMs) and children’s intakes of ‘nutrient-dense’ and ‘energy-rich foods’. In 2008, Finnish children, aged 10-12 years, completed a 16-item food frequency questionnaire and their parents completed a 27-item questionnaire to assess the FFCMs. Matching data existed for 564 child-parent pairs. Principal component analysis was conducted. The following eight dimensions of FFCM were found: ‘health and natural content’, ‘ethical concerns’, ‘mood’, ‘convenience’, ‘price’, ‘sensory appeal’, ‘weight control’ and ‘familiarity’. The association between FFCM and children’s food intakes was analyzed by Spearman correlations and logistic regression corrected for gender, school class, gender of respondent parent, living with one parent and parental education. The results based on logistic regressions showed that the FFCMs ‘health and natural content’ and ‘sensory appeal’ were positively associated, ‘convenience’ was negatively associated with ‘nutrient-dense foods’ and ’ethical concern’ was negatively associated with ‘energy-rich foods’. Parents’ FFCMs should be considered when promoting healthy eating among children.     

Effect of heat treatment and homogenization on the rheological properties of aqueous parsnip suspensions

Parsnip (Pastinaca sativa) suspensions, at concentrations corresponding to a dilute and concentrated regime, were subjected to pasteurization, and heat treatments that favored β-elimination reactions and pectin methyl esterase activity. The different heat treatments were combined with homogenization. Physicochemical properties such as content of insoluble/soluble material and insoluble/soluble pectin were measured together with particle and rheological properties. Pectin methyl esterase activity led to a high yield of insoluble material and insoluble pectin, whereas β-elimination led to a high yield of soluble material and solubilized pectin. Homogenization after heat treatment resulted in increased solubilization of the pectin, especially after β-elimination reactions. Parsnip suspensions subjected to pectin methyl esterase activity exhibited the highest elastic modulus most likely due to the cross-linked pectin conferring rigidity to the cell walls. The content of insoluble material and the particle properties such as size and rigidity are important factor for the rheological properties of concentrated parsnip suspensions.     

Universal primers for species authentication of animal foodstuff in a single polymerase chain reaction

BACKGROUND: There are many DNA‐based systems for detecting animal species present in food and food products, applicable for food quality control and authentication. However, most (if not all) methods require more than one pair of primers and cannot be applied over a wide taxonomic range, e.g. identifying vertebrates and invertebrates with the same primers and protocols. RESULTS: A pair of primers is described here that allows in a single polymerase chain reaction the identification of animal species in food and processed (precooked, canned or smoked) food products over a wide taxonomic range. CONCLUSION: These primers permit the identification of most animal taxa employed in human nutrition, from invertebrates such as molluscs to higher vertebrates, distinguishing between species of the same genus. The short fragment amplified within the 16S rDNA exhibits phylogenetic value and could be considered universal based on the wide taxonomic range assayed. The primers are easy to use and accessible for laboratories with a modest budget, as well as being valuable for consumer information and to reveal food fraud. Copyright © 2012 Society of Chemical Industry