Search

Hyperbaric storage (HS) is a new food preservation alternative or even improvement of cold storage processes. HS of raw pork meat in pieces (PP) and raw bovine minced meat (BM) was compared to conventional refrigeration at 60 MPa/10 °C and 75 MPa/25 °C (conditions at which a previous work reported good potential for shelf life extension), on proteolytic enzymes, texture after cooking, and SEM of raw meat microstructure. Regarding enzymatic activities in PP meat, an overall reduction on the activity of cathepsins B, L, and D and calpains were observed, which were more pronounced for cathepsin B and calpains, with a reduction of 77.5 and 95.3% for PP samples stored at 60 MPa/10 °C and 47.3 and 90.9% for samples stored at 75 MPa/25 °C, respectively, after 60 days of storage. A different scenario was observed for BM samples, where enzymatic activities remained practically unchanged for both HS conditions (except for calpains), when compared to refrigerated storage. Indeed, the reduction of calpain activity in BM at 60 MPa/10 °C was comparable to that of refrigerated storage, while at 75 MPa/25 °C, a significant (p > 0.05) reduction on calpain activity was observed compared either with refrigeration and 60 MPa/10 °C from the 30th day of storage experiments onwards. Additionally, cathepsin L activity decreased along refrigerated storage (approximately 44.4%), while both HS conditions allowed to keep the enzymatic activity unchanged along storage. Regarding texture after cooking, 60 MPa/10 °C revealed to be the preservation condition that better maintained meat textural characteristics during storage. Furthermore, analysis by SEM showed a more pronounced effect of 75 MPa/25 °C on meat microstructure, with muscular fibers showing a smother appearance and a less individualized organization. These results contribute to deepen the knowledge of the effect of HS on raw meat, after previous results have revealed a good possibility of extending the shelf-life of raw bovine and pork meats by HS, either in combination with mild (10 °C) or room-like (25 °C) temperatures.

This work aimed to study refrigeration storage (4 °C for 23 days) of yoghurt produced at 43 °C under sub-lethal high pressure, at 10, 20, 30 and 40 MPa, in comparison with the fermentation process at atmospheric pressure (0.1 MPa). Lactic acid bacteria (S. thermophilus and L. bulgaricus, LAB) and quality parameters like pH, titratable acidity, syneresis and colour were evaluated, along with textural analyses to infer how pressure would impact the obtained yoghurt along storage. Higher fermentation pressures resulted in slightly lower LAB loads (a maximum of 1.01 Log (CFU/mL)) and increased the fermentation time (a maximum of 3 h 25 min), syneresis (a maximum of 44%), all for 40 MPa and firmness (a maximum of 2.5-fold) for 30 MPa. Under refrigeration, LAB were more active during the first 15 days of storage in yoghurts fermented under pressure (increasing loads up to 0.54 Log (CFU/mL)). Colour, pH and titratable acidity were not affected by pressure or storage. Further research is of interest to ascertain the biotechnological potential of fermentation processes under sub-lethal high pressure in general and in particular for yoghurt production.

Hyperbaric storage at room temperature (HS/RT: 75 MPa/25 °C) of vacuum-packaged fresh Atlantic salmon (Salmo salar) loins was studied for 30 days and compared to atmospheric pressure at refrigerated temperatures (AP/5 °C, 30 days) and RT (AP/25 °C, 5 days). Most of the fatty acids were not affected by storage conditions, with only a slight decrease of docosahexaenoic acid (DHA) content (n-3 polyunsaturated fatty acid) for AP samples, reflected in the lower polyene index values obtained and higher oxidation extent. For HS, a lower lipid oxidation extension and a slower increase of myofibrillar fragmentation index values were observed, when compared to AP samples. The volatile profile was similar for the HS and fresh samples, with the HS samples retaining fresh-like alcohols and aldehydes components, which disappeared in AP samples, mainly in AP/25 °C samples. The volatile profile for AP samples (5 and 25 °C) revealed mostly spoilage-like compounds due to microbial activity. Drip loss increased progressively during the 30 days of storage under HS, while a slight decrease of water holding capacity after 5 days was observed, increasing further after 30 days. Regarding textural properties, only resilience was affected by HS, decreasing after 30 days. So, HS/RT could represent an interesting extended preservation methodology of fresh salmon loins, since allows retaining important physicochemical properties for at least 15 days, while refrigeration after 5 days showed already volatile spoilage-like compounds due to microbial activity. Furthermore, this methodology allows additional considerable energy savings when compared to refrigeration.

Agrofood byproducts may be exploited as a source of biomolecules suitable for developing bioplastic materials. In this work, the feasibility of using starch, oil, and waxes recovered from potato chips byproducts for films production was studied. The recovered potato starch-rich fraction (RPS) contained an amylopectin/amylose ratio of 2.3, gelatinization temperatures varying from 59 to 71 °C, and a gelatinization enthalpy of 12.5 J/g, similarly to a commercial potato starch (CPS). Despite of its spherical and oval granules identical to CPS, RPS had a more amorphous structure and gave rise to low viscous suspensions, contradicting the typical B-type polymorph crystal structure and sluggish dispersions of CPS, respectively. When used for films production, RPS originated transparent films with lower roughness and wettability than CPS-based films, but with higher stretchability. In turn, when combined with RPS and CPS, oil or waxes recovered from frying residues and potato peels, respectively, allowed to develop transparent yellowish RPS- and CPS-based films with increased surface hydrophobicity, mechanical traction resistance, elasticity, and/or plasticity. Therefore, potato chips industry byproducts revealed to have thermoplastic and hydrophobic biomolecules that can be used to efficiently develop biobased plastics with improved surface properties and flexibility, opening an opportunity for their valorization. published

The mechanical properties of the extracellular environment are interrogated by cells and integrated through mechanotransduction. Many cellular processes depend on actomyosin-dependent contractility, which is influenced by the microenvironment's stiffness. Here, we explored the influence of substrate stiffness on the proteome of proliferating undifferentiated human umbilical cord-matrix mesenchymal stem/stromal cells. The relative abundance of several proteins changed significantly by expanding cells on soft (∼3 kPa) or stiff substrates (GPa). Many such proteins are associated with the regulation of the actin cytoskeleton, a major player of mechanotransduction and cell physiology in response to mechanical cues. Specifically, Cofilin-1 levels were elevated in cells cultured on soft comparing with stiff substrates. Furthermore, Cofilin-1 was de-phosphorylated (active) and present in the nuclei of cells kept on soft substrates, in contrast with phosphorylated (inactive) and widespread distribution in cells on stiff. Soft substrates promoted Cofilin-1-dependent increased RNA transcription and faster RNA polymerase II-mediated transcription elongation. Cofilin-1 is part of a novel mechanism linking mechanotransduction and transcription. published

Microbial transglutaminase (MTG) is an enzyme largely used in the food industry, mainly to improve food texture. However, many globular proteins show low susceptibility to the action of this enzyme. High-pressure processing (HPP), being able to change protein conformation, may be a useful tool to increase the accessibility of globular proteins to the action of MTG. Nevertheless, HPP conditions need to be carefully optimized to avoid the expected decrease of enzymatic activity observed above certain conditions of pressure (P), treatment time (t) or temperature (T). Pressure inactivation of MTG under different HPP conditions (200–600 MPa; 20–40 °C; 10–30 min) was evaluated employing a face-centered composite design at four different pH values (4–7). The regression models obtained presented high coefficients of determination and high F values, although they could not explain some of the associated variability. At all the pH values tested, the three main factors (P, T, and t) significantly (p < 0.05) affected the activity of MTG. At least 20% of MTG was inactivated when low pressures (200 MPa) were used at pH 4 and 5, whereas a higher pressure above 400 MPa was needed to obtain a similar inactivation at pH 6 or 7. MTG pressure-inactivation followed first-order kinetics under all tested conditions. Inactivation rate constants decreased with increasing pressure at constant temperature and pH 4, with a positive activation volume (Va), while the opposite was verified for the other pH values. Both activation energy (Ea) and Va were dependent on pH, however, at the lower pH values, Ea and Va did not vary significantly with pressure and temperature, respectively. Overall, MTG can be considered relatively resistant to pressure, particularly near its optimal pH. published

The impact of air-drying at 25 &deg, C, brining at 25%, and dry-salting (at 28% and 40%) on the quality and nutritional parameters of Ulva rigida were evaluated over six months of storage. Overall, the main changes occurred in physical aspects during storage time, with U. rigida intensifying its yellow/browning tones, which were more evident in salt-treated samples. The force necessary to fracture the seaweed also increased under all the preservative conditions in the first month. Conversely, the nutritional parameters of U. rigida remained stable during the 180 days of storage. All processed samples showed a high content of insoluble and soluble fibers, overall accounting for 55%&ndash, 57% dw, and of proteins (17.5%&ndash, 19.2% dw), together with significant amounts of Fe (86&ndash, 92 mg/kg dw). The total fatty acids pool only accounted for 3.9%&ndash, 4.3% dw, but it was rich in unsaturated fatty acids (44%&ndash, 49% total fatty acids), namely palmitoleic (C16:1), oleic (C18:1), linoleic (C18:2), linolenic (C18:3), and stearidonic (18:4) acids, with an overall omega 6/omega 3 ratio below 0.6, a fact that highlights their potential health-promoting properties.

The small amount of proteins in starch-rich food industry byproducts can be an advantage to crosslink with genipin and tailor the performance of biobased films. In this work, genipin was combined with non- purified starch recovered from industrial potato washing slurries and used for films production. Starch recovered from potato washing slurries contained 0.75% protein, 2 times higher than starch directly obtained from potato and 6 times higher than the commercial one. Starch protein-genipin networks were formed with 0.05% and 0.10% genipin, gelatinized at 75 °C and 95 °C in presence of 30% glycerol. Bluish colored films were obtained in all conditions, with the higher surface roughness (Ra, 1.22 μm), stretchability (elongation, 31%), and hydrophobicity (water contact angle, 127°) for 0.10% genipin and starch gelatinized at 75 °C. Therefore, starch-rich byproducts, when combined with genipin, are promising for surpassing the starch-based films hydrophilicity and mechanical fragilities while providing light barrier properties.

Fundamental rheology, differential scanning calorimetry and infrared spectroscopy have been used to evaluate the effect of a cationic polysaccharide, chitosan, on the gelatinization, gel formation and retrogradation of maize starch samples, under acidic aqueous conditions. Moderate acidic conditions (0.1molL(-1) acetic acid) have shown a (slight) positive effect on starch gelatinization process and structure development. The presence of chitosan increased the DSC onset gelatinization temperature and also shifted the onset of the storage modulus increase to higher temperatures. Formation of the starch gel, mainly gelation of the leached-out amylose, is somehow hindered by the presence of the cationic polysaccharide and, therefore, the retrogradation of starch at very early stage can be delayed by addition of chitosan. However, long-term retrogradation was slightly increased. FTIR pectroscopy did not reveal any significant interaction between both polysaccharides what is in accordance with the observed rheological behavior. Small additions of chitosan to starch-rich systems may be a useful strategy to obtain new textures with novel phase transition behaviors.

Particles of titanium dioxide were prepared in the presence of europium ions (TiO 2 :Eu) by a solvothermal method and thermal annealed in air at 500 °C. The spectroscopic properties of TiO 2 :Eu particles were analyzed indicating that the Eu 3+ ions are likely distributed at the surface or near the surface of the titanium dioxide particles. The photoluminescence analysis showed that the intraionic emission was strongly sensitive to reduced pressure conditions, as seen by its absence under vacuum conditions. The ion emission was re-established as soon as the atmosphere was restored. Additionally, the ion integrated emission intensity follows a linearly dependence with pressure in the range of 150–800 mbar revealing a high sensitivity to small variations in pressure, which is an unprecedented result. This innovation will allow the study of new technologies in the area of low vacuum sensors where TiO 2 :Eu may act as the active element of an optical sensor for a pressure device.

Here, we report on the electrospinning of poly(vinylidene difluoride-co-trifluoroethylene) (P(VDF-TrFE)) copolymer fibrous membranes decorated with titanium dioxide/graphene oxide (TiO2/GO). The presence of the TiO2/GO increases the photocatalytic efficiency of the nanocomposite membrane towards the degradation of methylene blue (MB) when compared with the membranes prepared with naked TiO2, in UV and particularly in the visible range. Even a low content (3 %, w/w) of TiO2/GO in the fibers yields excellent photocatalytic performance by degrading similar to 100 % of a MB solution after 90 min of visible light exposure. This may be attributed to a rapid electron transport and the delayed recombination of electron-hole pairs due to improved ionic interaction between titanium and carbon combined with the advantageous electric properties of the polymer, such as high polarization and dielectric constant combined with low dielectric loss. Thus, a promising system to degrade organic pollutants in aqueous or gaseous systems under visible light irradiation has been developed., This work was supported by FEDER through the COMPETE Program and by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Project PEST-C/FIS/UI607/2014. Thanks are also due to FCT/MEC for the financial support to the QOPNA research Unit (FCT UID/QUI/00062/2013) (also through national founds, co-financed by FEDER within the PT2020 Partnership Agreement). P. A. A. P. Marques thanks the FCT Investigator Program 2013 (IF/00917/2013). Nuno A. F. Almeida and P. M. Martins thank the FCT for grants SFRH/BD/70300/2010 and SFRH/BD/98616/2013, respectively. Financial support from the Basque Government Industry Department under the ELKARTEK Program is also acknowledged. SLM thanks the Diputacion Foral de Bizkaia for financial support under the Bizkaia Talent program, European Union's Seventh Framework Programme, Marie Curie Actions-People, and Grant Agreement No. 267230., info:eu-repo/semantics/publishedVersion

The objectives of the present study were to assess how structural and gelation properties of soy protein isolates (SPIs) are affected by the characteristics of the soybean meal starting material used for protein extraction. The different degree of denaturation and aggregation due to processing treatments undergone by the soybean meals significantly affect the soy protein structural organization and functional properties. The main type of interaction responsible for the aggregates differed in the commercial and laboratory isolates, thus impacting on the protein composition of the soluble fraction of the different isolates. Spectroscopy analysis revealed that the commercial SPIs differ from the lab samples essentially due to the degree of protein aggregation and to differences in the tertiary structure (amide II). At the structural level, the lab-prepared SPIs obtained from the raw soy meal subjected to more extensive processing treatments is the one closest to the commercial samples, differentiating itself from the other laboratory isolates by the aggregation state. However, some extent of pre denaturation may be beneficial for the gelation performance of the soy protein samples, decreasing the gelation temperature and producing gels with higher stiffness and elastic character. On the contrary, extensive protein denaturation originate thermodynamically stable aggregates, water insoluble macro-aggregates less unfolded and dissociated by the heat treatment, being less available to integrate the three-dimensional network. published

Variations on fermentation conditions (temperature, pressure, etc.) can bring novel characteristics to fermentative processes and the respective final products. Regarding yogurt, both bacteria metabolism and physical properties of gel may be affected, resulting in different yogurts. Therefore, lactic acid fermentation was performed under different combinations of pressure (0.1, 10 and 30 MPa) and temperature (35, 43 and 50 °C), and microbiological and physical properties of the yogurts obtained were analyzed. Fermentation conditions affected the microbial growth, with Streptococcus thermophilus being more sensitive to the combination of high temperatures and pressures than Lactobacillus bulgaricus. Regarding physical properties, both syneresis and texture were influenced by fermentation conditions. Yogurts fermented at 10 MPa presented interesting features, with syneresis similar to control yogurts and a firm texture. Therefore, the fermentative conditions can be changed not only to regulate the fermentation kinetics, but also to produce a final product with different properties. Therefore, this approach opens the possibility of applying this type of strategy to a wide range of food fermentative processes, with potential to improve food quality and to create and develop food products with novel characteristics.

Soy protein hydrolysates (SPH) with different degrees of hydrolysis (DH 0-16%) were obtained by varying the time of hydrolysis with bromelain. The objective of this study was to evaluate how selected techno-functional properties (gelation, emulsification) of SPH were affected by the presence of a non-gelling polysaccharide. A slight hydrolysis was beneficial to increase gel strength. Also, the emulsifying activity was improved for low DHs, whereas hydrolysis was detrimental for emulsion stability. Under certain conditions the presence of the non-gelling polysaccharide was beneficial to improve SPHs' functional properties, but the effect was in general complex and strongly dependent on both biopolymers' concentration and molecular weight. Nevertheless, it was demonstrated that by using SPH and galactomannan mixtures and controlling the biopolymers' concentration and molecular weight, improved functionalities can be obtained with useful applications in food formulation. published

Mixed solutions of poly(ethylene terephthalate) (PET) and three types of poly(lactic acid) (PLA; a commercial sample and two branched PLAs) were used to prepare nonwoven nanofibrous mats by electrospinning. These mats were used as supports for trypsin immobilization, with the aim of an application in whey protein hydrolysis. Covalent attachment of crosslinked trypsin aggregates to amine-derivatized PET/PLA mats, followed by reduction with sodium cyanoborohydride, gave the best immobilized trypsin activity and showed no enzyme leaching. The activity of immobilized trypsin was higher than that of free trypsin at pH 6, a pH value representative of sweet whey. The PET/PLA mats with immobilized trypsin could be stored at 4 °C in water for at least 30 days, and could be reused 8 times without loosing activity and without enzyme leaching.

Trypsin was successfully entrapped in situ into nanofibers of poly(ϵ-caprolactone) (PCL) prepared by electrospinning. The spinning dope was an emulsion consisting of an aqueous phase with the solubilized enzyme in a pH buffer plus an oil phase of the polymer solubilized in chloroform (CF)/dimethylformamide (DMF). The optimized materials were composed by random arrays of bead-free fibers with outer diameters in the range 110-180 nm without showing core-shell structure. The fiber size and morphology, membrane porosity and surface properties were shown to be influenced by the polymer concentration and the composition ratio of the solvent mixture, and also by the presence of the enzyme. The activity of the immobilized trypsin was studied toward both a low-molecular weight synthetic substrate (BAPNA) and a protein (casein). Fluorescence microscopy, the increasing hydrophilicity of the fibrous membrane and the observed catalytic activity confirmed the entrapment of the enzyme into the PCL nanofibers. The best activity retention (∼66% toward BAPNA) was achieved using 0.20 g/mL PCL in CF/DMF [75:25], with trypsin in an aqueous buffer at pH 7.1 in the presence of benzamidine and Span80. The immobilized enzyme showed satisfactory operational stability retaining ∼59% of its initial activity after five reaction cycles. Compared with the free enzyme, the storage (at 4 °C) and thermal stability of the immobilized enzyme were highly improved. The retained catalytic activity and the observed reusability can be explained by a heterogeneous distribution of the enzyme within the polymer fiber influenced by the electrostatic field during the electrospinning process, enabling a preferential location near the fiber surface but simultaneously assuring minimal leaching out during operations. Results suggest that trypsin-PCL fibrous membranes may be useful for concomitant proteolytic and separation commercial applications.

The effects of galactomannans with different molecular weights on the heat-induced gelation characteristics of soybean protein were investigated using dynamic small-strain rheometry, under conditions where the proteins carry a net negative charge (pH7). Microstructure of the resulting gels was investigated by confocal laser scanning microscopy. Phase-separated systems were obtained with different morphologies and degree of phase separation, depending on both biopolymer concentrations and polysaccharide molecular weight. In general, a gelling enhancing effect on soy proteins was verified, despite extensive phase-separation processes observed at the higher polysaccharide molecular weight. This effect was demonstrated by an increase of the gelation rate, a decrease in the temperature at the onset of gelation, and an increase of gel stiffness and elastic character, with the length of polysaccharide chains. Overall, the results obtained established that the judicious selection of the galactomannan molecular weight may be used to modify the structure and gelation properties of soy proteins, originating a diversity of rheological characteristics and microstructures that will impact on the design of novel food formulations.

Lipid stability, physical properties and volatiles profile of vacuum-packaged fresh Atlantic salmon (Salmo salar) loins were evaluated after hyperbaric storage at low temperature (HS/LT: 60 MPa/10 °C) and compared to atmospheric pressure and conventional refrigeration (AP/5 °C) after 5, 15 and 30 days, and at low temperature (AP/10 °C), after 5 and 15 days. No variations in drip loss and water holding capacity were observed for HS/LT samples. Compared to AP, HS/LT caused lower changes on muscle fibres, visible by scanning electron micrographs, and a decrease of resilience property (only after 30 days). In addition, myofibrillar fragmentation index did not change at HS/LT. Fatty acids were generally not affected by the different storage conditions, while the polyene index at HS/LT was similar to fresh samples during the 30 days of storage, confirmed by the lower lipid oxidation state of these samples, compared to AP. According to the volatile profile (SPME-GC/MS), HS samples showed to be more similar to the fresh ones, retaining fresh-like alcohols and aldehydes, generally not detected in AP samples after 15 days, the latter presenting spoilage-related compounds probably derived from microbial activity. According to these results, HS/LT represents a promising preservation methodology for fresh salmon loins (and fish in general), retaining better important physicochemical properties for 30 days, when compared to the conventional refrigeration.

Experimental data for the density, viscosity, refractive index, and surface tension of four sulfonium- and ammonium-based ionic liquids (ILs) with the common bis(trifluoromethylsulfonyl)imide anion were measured in the temperature range between 288.15 and 353.15K and at atmospheric pressure. The ILs considered include butyltrimethylammonium bis(trifluoromethylsulfonyl)imide, [N-4111][NTf2], tributyl-methylammonium bis(trifluoromethylsulfonyl)imide, [N-4441][NTf2], diethylmethylsulfonium bis(trifluoromethylsulfonyl)imide, [S-221] [NTf2], and triethylsulfonium bis(trifluoromethylsulfonyl)imide, [S-222][NTf2]. Based on the gathered results and on data taken from literature, the impact of the cation isomerism and of the size of the aliphatic tails, as well as the effect resulting from the substitution of a nitrogen by a sulfur atom as the cation central atom, on the thermophysical properties of sulfonium- and ammonium-based Its is discussed here. Remarkably, more symmetric cations present a lower viscosity for the same, and sometimes even for higher, alkyl chain lengths at the cation. Additional derivative properties, such as the isobaric thermal expansion coefficient, the surface thermodynamic properties and the critical temperature for the investigated ILs were also estimated and are presented and discussed. (C) 2014 Elsevier B.V. All rights reserved.

Aiming at providing a comprehensive study of the influence of the cation symmetry and alkyl side chain length on the surface tension and surface organization of ionic liquids (ILs), this work addresses the experimental measurements of the surface tension of two extended series of ILs, namely R,R'-dialkylimidazolium bis-Rtrifluoromethyl)sulfonyllimide ([C(n)C(n)im][NTf2]) and R-alkyl-3-methylimidazolium bis[ (trifluoromethyl)sulfonyl] imide ([C-n C(1)im]-[NTf2D, and their dependence with temperature (from 298 to 343 K). For both series of ILs the surface tension decreases with an increase in the cation side alkyl chain length up to aliphatic chains no longer than hexyl, here labeled as critical alkyl chain length (CACL). For ILs with aliphatic moieties longer than CACL the surface tension displays an almost constant value up to [C(12)C(1)im][NTf2] or [C(16)C(1)im][NTf2]. These constant values further converge to the surface tension of long chain n-alkanes, indicating that, for sufficiently long alkyl side chains, the surface ordering is strongly dominated by the aliphatic tails present in the IL. The enthalpies and entropies of surface were also derived and the critical temperatures were estimated from the experimental data. The trend of the derived thermodynamic Properties highlights the effect of the structural organization of the IL at the surface with visible trend shifts occurring at a well-defined CACL in both symmetric and asymmetric series of ILs. Finally, the structure of a long-alkyl side chain IL at the vacuum-liquid interface was also explored using Molecular Dynamics simulations. In general, it was found that for the symmetric series of ILs, at the outermost polar layers, more cations point one of their aliphatic tails outward and the other inward, relative to the surface, than cations pointing both tails outward. The number of the former, while being the preferred conformation, exceeds the latter by around 75%.

The influence of diverse galactomannans, differing mainly on the degree of branching (amount of galactose side chains along the main mannan backbone), on the heat-induced gelation of soybean proteins at pH 7, was investigated using dynamic oscillatory rheological measurements at low strain amplitude and microstructural analysis by confocal laser scanning microscopy. Rheological tests were performed during gel formation, induced by either isothermal heating or by heating/cooling at a constant rate. Two different protein concentrations were analysed, one in the vicinity of the critical gel conditions and the other corresponding to a well developed gel, whereas the galactomannan concentration ranged from 0 to 0.5%. The presence of the galactomannan promoted the gelation to occur for protein concentration below the critical gelation of soybean proteins alone, decreased the gelling temperature and had a positive effect on the gel strength of the heat-induced gels. These effects were more pronounced as the degree of branching decreases. The consequence of demixing and phase separation was dependent on biopolymer concentration and galactomannan branching, resulting in an array of microstructures, spanning emulsion-like, bicontinuous and aggregated morphologies. Structure development within the galactomannan-rich phases, dependent on the branching degree and on the capability of the galactomannan for self-association, may have played a role in the phase separation and viscoelasticity of the final gels. It was demonstrated that by using soybean proteins and galactomannan mixtures at above phase separation concentrations and controlling the polymer concentration and the length of the unsubstituted polysaccharide backbone, tailor-made viscoelasticities and microstructures can be obtained with useful applications in food formulation.

A agricultura de precisão permite, pelo uso de delimitação de lavouras por coordenadas georreferenciadas, um planejamento mais racional do manejo de nutrientes, incidência de pragas, umidade do solo, plantas daninhas, além de seleção de cultivares em função de sua adaptabilidade às diferentes condições identificadas nas áreas cultivadas. Com isso, o objetivo do presente trabalho foi avaliar a distribuição espacial da condutividade elétrica do extrato de saturação, carbono orgânico total e matéria orgânica em um solo Neossolo Flúvico. O experimento foi conduzido em uma área com malha regular 4 x 4 m, totalizando com 49 pontos, onde foram coletadas amostras nas camadas de 0- 0,20 m para analisar a condutividade elétrica do extrato de saturação, carbono orgânico total e matéria orgânica. As variáveis foram analisadas por meio da estatística descritiva e de ferramentas de geoestatística. As variáveis apresentaram distribuição normal, os semivariogramas se ajustaram a um modelo esférico, a variabilidade do carbono orgânico total e matéria orgânica apresentaram moderadas, a condutividade elétrica do extrato de saturação apresentou fraca dependência espacial. Os mapas de isolinhas apresentaram homogeneidade e similaridade, os mapas condutividade elétrica do extrato de 0-0,20 m foram inversamente proporcionais aos da matéria orgânica e do carbono orgânico. A B S T R A C T Precision agriculture allows, by the use of delimitation of crops for georeferenced coordinates, more rational planning of the management of nutrients, pests, soil moisture, weeds, and cultivar selection due to its adaptability to different conditions in the areas identified cultured. With it, the objective of this study was to evaluate the spatial distribution of the electrical conductivity of the saturation extract, total organic carbon and organic matter in soil Fluvic Neosol. The experiment was conducted in an area with regular mesh 4 x 4 m, with a total of 49 points, samples were collected in layers from 0 to 0.20 m to analyze the electrical conductivity of the saturation extract, total organic carbon and organic matter. The variables were analyzed using descriptive statistics and geostatistical tools. The variables were normally distributed, the semivariogram adjusted to a spherical model, the variability of total organic caborn and organic matter showed a moderate electrical conductivity of the saturation extract showed weak spatial dependence. The contour maps showed homogeneity and similarity maps the electrical conductivity of the extract of 0-0.20 m was inversely proportional to the organic matter and organic carbon. Key-Words: Geostatistics, salinity, total organic carbon, organic matter

Starches isolated from six maize landraces from Brazil were investigated for their physicochemical, morphological, structural and thermal properties and compared to a commercial maize starch (COM). Similarities (chemical composition) and differences (structural characteristics) were observed. The crystallinity of starches ranged between 18.5 and 25.0%. The swelling power at 65°C ranged between 3.00 g/g Pires (PIR) and 4.82 g/g Mato Grosso (MT), whereas at 90°C varied between 18.8 g/g (PIR) and 23.9 g/g (MT), differing from COM, i.e., 14.6 g/g. The starch granule's morphology and size determined by SEM showed polyhedral and spherical shapes and a heterogeneous size distribution between 1.7 and 25 µm. The gelatinization process studied by DSC showed that transition temperatures (T0, Tp, Tc) ranged between 61.0–65.9, 67.5–71.7, and 75.2–76.8°C, respectively, and enthalpies (ΔHgel) between 11.4 and 13.3 (J/g). The retrogradation properties were analyzed after storage for 7, 14, and 40 days at 4°C; the retrogradation degree changed with the time and among the different starches, as well as the transition temperatures and enthalpies, which were lower than those observed for the gelatinization process. Other parameters like gelatinization and retrogradation temperature range (Rgel, Rret) and PHI were analyzed. Rgel was faster for BR and slower for MT, while Rret was broader than the corresponding gelatinization and PHI was not significantly different among the studied starches, except for the BR (slightly higher value).

While values for thermophysical properties of ionic liquids are becoming widely available, data for ionic liquid mixtures are still scarce. In an effort to overcome this limitation and understand the behavior of ionic liquid mixtures, novel data for the surface tension of mixtures composed of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [C(4)mim][NTf2], with other ionic liquids with a common anion, namely 1-butyl-2,3-dimethylimidazolium, [C(4)C(1)mim](+), 3-methyl-1-propylpyridinium, [C(3)mpy](+), 1-methyl-1-propylpyrrolidinium, [C(3)mpyr](+), and 1-methyl-1-propylpiperidinium, [C(3)mpip](+), were measured at T = 298.2 K and atmospheric pressure over the entire composition range. From the surface tension deviations derived from the experimental results, it was possible to infer that the cation alkyl chain length of the second ionic liquid constituting the mixture has a stronger influence in the ideal mixture behavior than the type of family the ionic liquid cation belongs to. The Gibbs adsorption isotherms, estimated from the experimental values, show that the composition of the vapor-liquid interface is not the same as that of the bulk and that the interface is richer in the ionic liquid with the lowest surface tension, [C(4)mim][NTf2]. (C) 2013 Elsevier Ltd. All rights reserved.

The demand for proteins is rising and alternatives to meat proteins are necessary since animal husbandry is expensive and intensive to the environment. Plant proteins appear as an alternative; however, their techno-functional properties need improvement. High-pressure processing (HPP) is a non-thermal technology that has several applications including the modification of proteins. The application of pressure allows modifying proteins' structure hence allowing to change several of their properties, such as hydration, hydrophobicity, and hydrophilicity. These properties may influence the solubility of proteins and their ability to stabilize emulsions or foams, create aggregates or gels, and their general role in stability and texture of food commodities. Commonly HPP decreases the proteins' solubility yet increasing their surface hydrophobicity exposing sulfhydryl groups, which promotes aggregation or gelation or enhance their ability to stabilize emulsions/foams. However, these effects are not verifiable for all the proteins and are immensely dependent on the type and concentration of the protein, environmental conditions (pH, ionic strength, and co-solutes), and HPP conditions. This review collects and critically discusses the available information on how HPP affects the structure of plant proteins and how their techno-functional properties can be tailored using this approach.

Fundacao para a Ciencia e a Tecnologia (FCT/MCTES) - SFRH/BD/100563/2014 ; SFRH/BPD/82264/2011 ; PTDC/EQU-FTT/118800/2010 ; PTDC/CTM-NAN/121274/2010 ; IF/00210/2014/CP1244/CT0003 ; UID/Multi/04551/2013 ; UID/CTM/50011/2013 European Research Council (ERC) - ERC-2013-StG-337753 FCT/MEC - RECI/BBB-BQB/0230/2012 This paper reports the thermal, thermodynamic, thermophysical and surface properties of eight ionic liquids with fluorinated alkyl side chain lengths equal or greater than four carbon atoms. Melting and decomposition temperatures were determined together with experimental densities, surface tensions, refractive indices, dynamic viscosities and ionic conductivities in a temperature interval ranging from (293.15 to 353.15) K. The surface properties of these fluorinated ionic liquids were discussed and several thermodynamic functions, as well as critical temperatures, were estimated. Coefficients of isobaric thermal expansion, molecular volumes and free volume effects were calculated from experimental values of density and refractive index and compared with previous data. Finally, Walden plots were used to evaluate the ionicity of the investigated ionic liquids. publishersversion published

The air–liquid interfacial tensions of eight ionic liquids, from (298 to 343) K, are presented in this work. The studied ionic liquids are formed by the fixed 1-ethyl-3-methylimidazolium cation combined with the anions acetate, dicyanamide, dimethylphosphate, methylphosphonate, methanesulfonate, thiocyanate, tosylate, and trifluoromethanesulfonate. The selected ionic liquids allowed a comprehensive study through the influence of the anion nature on the surface tension and on their surface ordering. A slight dependence of the surface tension with the ionic liquid molar volume was identified. The surface thermodynamic functions are mainly controlled by the anion which constitutes a given ionic liquid. The hypothetical critical temperatures of all ionic liquids were estimated by means of the Eotvos and Guggenheim correlations and are presented.

Ionic liquids (ILs) with improved hydrogen-bonding acceptor abilities, such as acetate-based compounds, have shown great potential for CO2 capture and biomass dissolution. In this context, the knowledge of the thermophysical properties of acetate-based fluids is essential for the design and scale-up of related processes. However, at this stage, acetate-based ILs are still poorly characterized. In this work, four thermophysical properties, specifically, density, viscosity, refractive index, and surface tension, were determined for five acetate-based ILs. Both protic and aprotic ILs were investigated, namely, N,N-dimethyl-N-ethylammonium acetate, 1-ethylimidazolium acetate, 1-ethyl-3-methylimidazolium acetate, 1-butyl-3-methylimidazolium acetate, and 1-butyl-1-methylpyrrolidinium acetate. From the temperature dependence of the measured properties, additional properties, such as the isobaric thermal expansion coefficient, the surface entropy and enthalpy, and the critical temperature, were further estimated.

N-maltosyl-chitosans with different substitution degrees were prepared by reductive N-alkylation. Dynamic shear experiments were used to study the influence of degree of substitution (DS), polymer concentration and temperature on the viscoelastic properties of these semi-synthetic polysaccharides. The attachment of the disaccharide as side chains drastically changed solubility and rheological behaviour of the ‘native’ biopolymer. At lower DS extensive interchain associations may develop, yet allowing for water solubility, but originating temporary gel-like networks. At higher DS, the bulky of the disaccharide groups leads to less extensive hydrogen bonding or hydrophobic interactions and the viscoelastic profile resembles more to an entangled high-molecular weight polymer. The combined effect of different types of interactions among the polysaccharide chains, including topological entanglements, but also more specific hydrogen bonding and hydrophobic interactions, is responsible for several peculiar rheological characteristics, such as strain-induced structuring, complex relaxation processes, elastic plateaus at low frequencies, anomalous scaling behaviour on concentration regarding the relaxation times and modulus, and complex temperature effects, including departures to the time–temperature superposition principle, which are strongly dependent on the polymer concentration, DS and temperature. Therefore, the explored approach demonstrated that branched chitosan derivatives could be produced with varied and tailorable rheological properties in aqueous media with expected enhanced applications.

Oscillatory and steady-shear rheological methods as well as scanning electron microscopy were used to characterize silica (SiO 2 )/galactomannan dispersions. Particle loading and surface charge are found to strongly influence the composite structure and dynamics. When the particles were added above a minimum concentration, a sol–gel transition was induced. The SiO 2 /polysaccharide dispersions exhibited significant non-linearities, especially under ionic conditions that favor interparticle and particle–polysaccharide interactions, characterized by strong shear-thinning, diverging viscosities at low shear rates, apparent yield stress and high strain sensitivity. The mechanical spectra for the composite systems suggest that stress relaxation of these composites is effectively arrested by the presence of silica nanoparticles. Microstructural analysis revealed an ordering of the silica particles around the polymer chains. Polysaccharide chains act as templates for particle clustering leading to the formation of a particle-mediated transient biopolymer network, with particle clusters hindering polymer mobility and enhancing junction zones within the network.

Composite films made from chitosan, plasticizer, and incorporated silica nanoparticles were evaluated for their mechanical properties, thermal stability, water permeability, and surface characteristics. The influence of the chitosan amino group protonation upon the observed silica effects was also analyzed. Only slight differences between most of the properties of composite films and those of the biopolymer alone were observed. The lack of complete and uniform dispersion of the silica particles within the biopolymer matrix and the absence of relevant polymer-filler interactions in such composite membranes lead to a low level of interaction between the filler and the polymer, and only a reduced effect of the filler on the film properties. The silica effects worthy to mention are the decrease in Young's modulus and the increase in film elongation, and the slight influence on surface hydrophobicity and water vapour permeability, which were dependent on the neutralization pos-treatment process.

The capability to produce blend chitosan–whey protein films at acidic pH, carrying a high amount of protein, is demonstrated, even though under these conditions a pure whey protein film could not be obtained. The films are biphasic and characterized by a compositional gradient, with the downward film surface containing a lower amount of protein than the upward surface. The surface richer in protein was more hydrophobic than that richer in chitosan. The difference in composition and hydrophilicity between both surfaces increases with the amount of protein incorporated in the film. Increasing the protein amount decreased elongation at break and tensile strength but, in general, had little effect on water vapor permeability. Although some of the film functionality might be compromised due to the incompatibility between the polysaccharide and protein components within the film matrix, the blended films, especially those with intermediated protein amount, may have useful applications on those food systems where the edible films should break up during the cooking or mastication process.

The plums used to produce a traditional candied product, “Ameixa d’Elvas”, were obtained from two orchards, Vila Vicosa (VV) and Cano (CA). These orchards were selected because the fruits were behaving differently: (1) The day of harvesting for candying, established by the total soluble solids and titratable acidity, was one week earlier in VV; (2) VV yielded candied plums with good texture properties whereas CA gave poor processed fruits. In order to understand the origin of these differences, fruits from both orchards were harvested on the day established as the harvesting day for VV (day 1) and for CA (day 8). Comparable texture properties were obtained in firmness, rigidity and deformation work between the VV fresh plums harvested on day 1 and the CA plums harvested on day 8 but these were lower in CA when the flesh was analysed separately, in accordance with the activities of pectin methyl esterase (PME), polygalacturonase (PG) and cellulase (Cel). The increase of the intercellular area of parenchyma cells and the decrease in cell area caused by boiling, which resulted in a pronounced loss of textural properties, were partially recovered after the immersion of the fruits in sucrose syrup. The CA plums harvested on day 8 had a more pronounced degradation with boiling and lower recovery of cell shape, size and textural characteristics than had those of VV harvested on day 1. Upon candying, similar properties were observed for the fruits harvested on the same day: good candied products were observed for VV and CA fruits harvested on day 1 and poor candied products were observed for VV and CA fruits harvested on day 8. This work shows that the characteristics of the flesh of the fresh fruits are key parameters in defining the textural properties of the candied plum. The establishment of the harvesting moment for candying should take into account the changes that occur in the flesh of the plums during ripening.

A commercial gellan sample (Gelrite) and a gellan-like polymer (JB3) obtained by exposure of the producing strain to chemical mutagenesis were subjected to partial acid hydrolysis and the resultant oligosaccharides were identified by Electrospray Mass Spectrometry (ESI-MS) and Tandem Mass Spectrometry (ESI-MS/MS and MS n ). In both gellans, the main fragments were in accordance with the tetrasaccharide repeating unit, d -Glucose (Glc)- d -Glucuronic acid (GlcA)- d -Glucose (Glc)- l -Rhamose (Rha), described for the wild-type gellan, showing the higher acid lability of the Rha-(1 → 3)-Glc linkage when compared to the (1 → 4) of the other residues. Under the experimental conditions used in the study, as expected, no acyl substituents were observed in the commercial gellan but in JB3 oligosaccharides a glyceryl moiety was identified, substituted in the 3-linked Glc residue. Furthermore, the analysis of the MS/MS and MS n spectra of both gellans allowed the identification of structural details, some of them not yet reported for these exopolysaccharides. The presence of oligosaccharides with single Glc and Rha residues substituent of the tetrasaccharide unit of gellan may represent novel side chains of the backbone unit that to our knowledge have never been reported previously for the gellan exopolysaccharide.

Electrospinning was used to produce self-supporting nanofibrous poly(ethylene terephthalate) membranes with good mechanical properties and straightforward handling. The application of this type of membranes in apple juice clarification process was investigated. Processing characteristics and quality parameters of apple juice were analyzed in order to compare the proposed method to traditional clarification techniques. In general, the apple juice obtained from electrospun nanofiber membrane filtration revealed physico-chemical characteristics comparable to those from juice clarified by ultrafiltration or by conventional clarification using filtering aids. Nevertheless, the new process showed a high flux performance and revealed to be much faster, simple and more economical than the traditional processes. This work demonstrated the filtration potential of an electrospun PET membrane thus introducing a new concept of clarification and opening new approaches for the juice processing industry or even for other food industry fields.

The plums ( Prunus domestica L.) of a specific ‘Green Gage’ variety, “Rainha Claudia Verde”, are used to produce the candied product “Ameixa d’Elvas”. The candying process consists in boiling the intact plums in water and further immersion in sucrose syrup until 75 °Brix. Scanning electron microscopy of unprocessed plums revealed perfectly turgid parenchyma isodiametric cells with few intercellular spaces and the boiled plums showed a loss of intercellular adhesion of parenchyma cells and ruptures on the vascular strand structure. However, candied plums showed recovery of the turgidity and cell-to-cell adhesion of parenchyma cells. Texture analysis showed that the unprocessed plums had a fairly hard texture, improved by the presence of the skin. Firmness, rigidity, and deformation work had a sharp decrease upon boiling. However, after candying, an increase of firmness and deformation work was observed, also improved by the skin. Microstructure and texture recovery of the candying product suggests the formation of a jam-like structure in the middle lamella region promoted by the syrup. Nevertheless, cell adhesion recovery is limited by the extent of the disruption of the tissues during the boiling process. This is the first report concerning texture and microstructure changes of plums occurring during the candying process.

The effect of pressure treatments of 100 and 200 MPa (10 and 20 min) and of thermal blanching at 70 °C, 80 °C and 98 °C (1 and 2.5 min), on sweet green and red bell peppers was compared. Pressure treated peppers showed a lower reduction on soluble protein and ascorbic acid contents. Red peppers presented even an increased content of ascorbic acid (15–20%), compared to the untreated peppers. Peroxidase and pectin methylesterase (whose activity was only quantifiable in green peppers) showed a higher stability to pressure treatments, particularly the latter enzyme, while polyphenol oxidase was inactivated to the same final level by the thermal blanching and pressure treatments. Pressure treatments resulted in comparable (in green pepper) to higher (in red pepper) microbial loads compared to blanching. Pressure treated green and red peppers presented similar to better firmness before and after tunnel freezing at −30 °C, compared to thermally blanched peppers, particularly those blanched at 98 °C. The results indicated that pressure treatments of 100 and 200 MPa can be used to produce frozen peppers with similar to better nutritional (soluble protein and ascorbic acid) and texture (firmness) characteristics, comparable activity of polyphenol oxidase and higher activity of pectin methylesterase, while pressure treated peppers show a higher level of peroxidase activity. It would be interesting to use higher pressures in future studies, as an attempt to cause a higher reduction on microbial load and on enzymatic activity.

This study describes the preparation and characterization of nanofibrous mats obtained by electrospinning poly(ethylene terephthalate) (PET) solutions in trifluoroacetic acid/dichloromethane (TFA/DCM). Special attention was paid to the effect of polymer concentration and solvent properties on the morphology, structure, and mechanical and thermal properties of the electrospun nonwovens. The results show that the spinnable concentration of PET solution in TFA/DCM solvents is above 10 wt %. Mats have nanofibrous morphology with fibers having an average diameter in the range of 200–700 nm (depending on polymer concentration and solvent composition) and an interconnected pore structure. Higher solution concentration favors the formation of uniform fibers without beads and with higher diameter. Morphology and fiber assembly changed with the solvent properties. Solvent mixtures rich in TFA, i.e., those with higher dielectric constant and lower surface tension, originated fibers with small diameter. However, due to the lower volatility, those solvent mixtures also produced more branched and crosslinking fibers, with less morphologic uniformity. Mechanical properties (Young's modulus, ultimate strength, and elongation at break) and thermal properties (glass transition, crystallization, and melting) have been studied for the PET electrospun nanomats and compared with those of the original polymer. Solvent effect on fiber crystallinity was not significant, but a complex effect was observed on the mechanical properties of the electrospun mats, as a consequence of the different structural organization of the fibers within the mat network. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 460–471, 2008

We have investigated, both theoretically and experimentally, the balance between the presence of alkyl and perfluoroalkyl side chains on the surface organization and surface tension of fluorinated ionic liquids (FILs). A series of ionic liquids (ILs) composed of 1-alkyl-3-methylimidazolium cations ([C(n)C(1)im] with n = 2, 4, 6, 8, 10, or 12) combined with the perfluorobutanesulfonate anion was used. The surface tensions of the investigated liquid salts are considerably lower than those reported for non fluorinated ionic liquids. The most surprising and striking feature is the identification, for the first time, of a minimum at n = 8 in the surface tension versus the length of the IL cation alkyl side chain. Supported by molecular dynamics (MD) simulations, it was found that this trend is a result of the competition between the two nonpolar domains (perfluorinated and aliphatic) pointing toward the gas-liquid interface, a phenomenon which occurs in ILs with perfluorinated anions. Furthermore, these ILs present the lowest surface entropy reported to date.

This work explores the n vs. iso isomerization effects on the physicochemical properties of different families of ionic liquids (ILs) with variable aromaticity and ring size. This study comprises the experimental measurements, in a wide temperature range, of the ILs' thermal behaviour, heat capacities, densities, refractive indices, surface tensions, and viscosities. The results here reported show that the presence of the iso-alkyl group leads to an increase of the temperature of the glass transition, T-g. The isopyrrolidinium (5 atoms ring cation core) and iso-piperidinium (6 atoms ring cation core) ILs present a strong differentiation in the enthalpy and entropy of melting. Non-aromatic ILs have higher molar heat capacities due to the increase of the atomic contribution, whereas it was not found any significant differentiation between then and iso-alkyl isomers. A small increase of the surface tension was observed for the non-aromatic Its, which could be related to their higher cohesive energy of the bulk, while the lower surface entropy observed for the iso isomers indicates a structural resemblance between the IL bulk and surface. The significant differentiation between ILs with a 5 and 6 atoms ring cation in the n-alkyl series (where 5 atoms ring cations have higher surface entropy) is an indication of a more efficient arrangement of the non-polar region at the surface in ILs with smaller cation cores. The ILs constituted by non aromatic piperidinium cation, and iso-alkyl isomers were found to be the most viscous among the studied Its due to their higher energy barriers for shear stress. (C) 2016 Published by Elsevier B.V.

A novel approach is described using chitosan–genipin films as a sustainable method for wine preservation. Films prepared from fungi and from shrimp by-products showed similar mechanical and chemical properties. In addition, shrimp derived films showed no IgE positive reaction against shellfish allergenic compounds. The chitosan–genipin films were used to produce white wines without the addition of sulphur dioxide as a preservative. These wines showed lower susceptibility to browning, with organoleptic characteristics comparable to those prepared using sulphur dioxide. It is shown that the formation of iron-tartrate–chitosan complexes promotes the decrease of iron and other metal availability, minimizing oxidation reactions, as well as inhibiting microbial growth. The overall volatile character of the wines was maintained. However, the presence of chitosan–genipin films promotes the occurrence of Maillard and Strecker reactions, producing volatile compounds with positive wine aroma scents. The use of chitosan–genipin films in winemaking is an innovative, green and environmentally friendly technology that could be easily implemented at an industrial scale with no additional costs.

Isothermal crystallization and structure development was studied for three different waxy crude oils. The transformation from sol to gel was followed by small-amplitude dynamic rheometry, which closely tracks the development of the three-dimensional network as the initially formed crystallites grow, aggregate, and interact with each other. The kinetics of the crystallization-induced gelation was analyzed with the phenomenological Avrami model. The analysis was performed for a temperature range of about 15 K and was limited to the early stages of transformation. Both the Avrami exponent n and the rate constant k are dependent on the crystallization temperature, meaning that the nucleation and crystal growth mechanisms and rates are dependent on the degree of supercooling. Higher Avrami constants and lower Avrami coefficients (higher rate of crystal growth) were observed under higher supercooling conditions. The results discussed allowed the predominant mechanisms for nucleation and crystal growth, occurring as a function of temperature (i.e., supercooling degree) and waxy crude oil composition, to be defined.

Histological and mechanical studies were conducted to evaluate the changes that are conferred by a traditional sun-drying process on the texture and microstructure of a Portuguese pear cultivar (Pyrus communis L. var. S. Bartolomeu). Sun-drying processing of the pears results in loss of water, cell flattening and shrinkage, loss of cellular adhesion, and even loss of cell wall integrity. The sun-drying process significantly reduced the hardness and fracturability of the pear tissues, while increasing their cohesiveness, springiness and adhesiveness. The results obtained by texture and microstructure analysis of the fresh pear flesh reflect essentially an unified matrix comprising well-packed cells strongly bonded together whereas those of the sun-dried pear flesh pointed out a soft solid with many individual cells distributed in a soft matrix, explaining its softer and chewy texture.

The undeveloped doughs of two wheat flours differing in technological performance were characterized at the supramolecular level, by fundamental small-deformation oscillatory rheology and shear viscometry, and at the molecular level, by nuclear magnetic resonance (NMR) spectroscopy. For the harder variety, the higher storage moduli indicated lower mobility of the protein/water matrix in the 0.001−100 s range. Conversely, 1H NMR indicated higher molecular mobility in the sub-microsecond range for protein/water, whereas starch was found to be generally more hindered. It is suggested that faster protein/water motions are at the basis of the higher structural rearrangement indicated by tan δ for the harder variety. Rheological effects of heating−cooling reflect mainly starch behavior, whereas 1H NMR spectra and relaxation times give additional information on component mixing and molecular mobility. The heated softer variety dough formed a rigid lattice and, although a similar tendency was seen for the hard va...

Many applications involving ionic liquids (ILs) require the knowledge of their interfacial behaviour, such as wettability and adhesion. In this context, herein, two approaches were combined aiming at understanding the impact of the IL chemical structures on their wettability on both polar and non-polar surfaces, namely: (i) the experimental determination of the contact angles of a broad range of ILs (covering a wide number of anions of variable polarity, cations, and cation alkyl side chain lengths) on polar and non-polar solid substrates (glass, Al-plate, and poly-(tetrafluoroethylene) (PTFE)); and (ii) the correlation of the experimental contact angles with the cation–anion pair interaction energies generated by the Conductor-like Screening Model for Real Solvents (COSMO-RS). The combined results reveal that the hydrogen-bond basicity of ILs, and thus the IL anion, plays a major role through their wettability on both polar and non-polar surfaces. The increase of the IL hydrogen-bond accepting ability leads to an improved wettability of more polar surfaces (lower contact angles) while the opposite trend is observed on non-polar surfaces. The cation nature and alkyl side chain lengths have however a smaller impact on the wetting ability of ILs. Linear correlations were found between the experimental contact angles and the cation–anion hydrogen-bonding and cation ring energies, estimated using COSMO-RS, suggesting that these features primarily control the wetting ability of ILs. Furthermore, two-descriptor correlations are proposed here to predict the contact angles of a wide variety of ILs on glass, Al-plate, and PTFE surfaces. A new extended list is provided for the contact angles of ILs on three surfaces, which can be used as a priori information to choose appropriate ILs before a given application.

Determination of material properties and functions is a crucial step towards optimization of fabrication methods as well as the development of electrospun nanofibers for use in e.g. food engineering applications. This work focused in evaluating physical and mass transfer properties of simple poly -caprolactone nanofibers (PCL membrane), and poly ε-caprolactone nanofibers with encapsulated trypsin (E-PCL membrane), in view of their future use in a catalytic filter reactor. PCL membranes registered high hydrophobicity values, while E-PCL membranes revealed stronger mechanical properties and an increase of mass due to water incorporation. A decrease of average pore size in the range of 30% to 40% was observed for E-PCL membranes and an average pore diameter of 1/3 of the size was registered when compared to the PCL membrane; this difference was shown to be significant enough to influence the transport of larger molecules (e.g. bovine serum albumin). Release experiments of active compounds (lysozyme, bovine serum albumin and lactoferrin) were successfully described by a model which accounts for both Fick and Case II transport the linear superimposition model. Results show that the transport mechanism is influenced by the type of active compound and by membranes physical properties., The present study was developed under the scope of the NanoBioCats project (PTDC/CTM-POL/112289/2009), funded by the Portuguese Science and Technology Foundation (Fundação para a Ciência e a Tecnologia – FCT). This work was also supported by the COMPETE program (funded by the European Union fund, FEDER under the framework of QREN (Programa Operacional Regional do Norte (ON.2 – O Novo Norte; FEDER))) through projects NORTE-07-0124-FEDER-000028 and NORTE-07-0124-FEDER-000069. Also, the authors thank Strategic Projects PEst-OE/EQB/LA0023/2013, PEst-C/EQB/LA0006/2013 – FCOMP-01-0124-FEDER-37285 and PEst-C/QUI/UI0062/2013 – FCOMP-01-0124-FEDER-037296. The Fundação para a Ciência e Tecnologia (FCT, Portugal) through grant SFRH/BD/73178/2010

Analysis of a purified fraction from acetone extracts of olive pulp and pomace by electrospray ionisation tandem mass spectrometry (ESI-MSn) showed the presence of oleuropein oligomers, whose occurrence has not been reported previously in the literature. The main ionic species (m/z 1613) in the ESI-MS spectrum was an oleuropein trimer containing three linkages through the hydroxytyrosol backbone. In both samples, oleuropein dimers (m/z 1075), trimers comprising two hydroxytyrosol linkages (m/z 1615), tetramers (m/z 2153) and pentamers (m/z 2691) were also detected by MS. The occurrence of oleuropein oligomers was also observed by nuclear magnetic resonance (NMR). 13C, 13C distortionless enhancement by polarisation transfer DEPT 90, 13C DEPT 135, gHSQC (heteronuclear single quantum coherence) and gHMBC (heteronuclear multiple bond coherence) spectra showed all carbon and proton resonances of oleuropein with the exception of the low-mobility and asymmetric signals of the aromatic rings. Since mature olives were used in this study, it is possible that the disappearance of oleuropein that has been described to occur with the olive fruit maturation, could be associated with the formation of phenolic oligomers together with lower-molecular-weight compounds resulting from its degradation. Copyright © 2006 Society of Chemical Industry

Methanol extracts of olive pomace (two-phase olive oil extraction) and olive pulp were analysed by reverse phase HPLC and the eluted fractions were characterised by electrospray ionisation mass spectrometry. This technique allowed the identification of some common phenolic compounds, namely, verbascoside, rutin, caffeoyl-quinic acid, luteolin-4-glucoside and 11-methyl-oleoside. Hydroxytyrosol-1 � - β-glucoside, luteolin-7-rutinoside and oleoside were also detected. Moreover, this technique enabled the identification, for the first time in Olea europaea tissues, of two oleoside derivatives, 6 � -β-glucopyranosyl- oleoside and 6 � -β-rhamnopyranosyl-oleoside, and of 10-hydroxy-oleuropein. Also, an oleuropein glucoside that had previously been identified in olive leaves was now detected in olive fruit, both in olive pulp and olive pomace. With the exception of oleoside and oleuropein, the majority of phenolic compounds were found to occur in equivalent amounts in olive pulp and olive pomace. Oleoside was the main phenolic compound in olive pulp (31.6mgg −1 ) but was reduced to 3.6mgg −1 in olive pomace, and oleuropein (2.7mgg −1 in the pulp) almost disappeared (