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1.
Molecules ; 24(16)2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31443147

RESUMO

The impact of air-drying at 25 °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%-57% dw, and of proteins (17.5%-19.2% dw), together with significant amounts of Fe (86-92 mg/kg dw). The total fatty acids pool only accounted for 3.9%-4.3% dw, but it was rich in unsaturated fatty acids (44%-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.


Assuntos
Fenômenos Químicos , Análise de Alimentos , Alimentos em Conserva/análise , Ulva/química , Análise de Alimentos/métodos , Conservação de Alimentos , Valor Nutritivo , Fatores de Tempo
2.
Langmuir ; 32(24): 6130-9, 2016 06 21.
Artigo em Inglês | MEDLINE | ID: mdl-27218210

RESUMO

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 ([CnC1im] 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.

3.
Fluid Phase Equilib ; 409: 458-465, 2016 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-27642224

RESUMO

Ionic liquids (ILs) with cyano-functionalized anions are a set of fluids that are still poorly characterized despite their remarkably low viscosities and potential applications. Aiming at providing a comprehensive study on the influence of the number of -CN groups through the surface tension and surface organization of ILs, the surface tensions of imidazolium-based ILs with cyano-functionalized anions were determined at atmospheric pressure and in the (298.15 to 343.15) K temperature range. The ILs investigated are based on 1-alkyl-3-methylimidazolium cations (alkyl = ethyl, butyl and hexyl) combined with the [SCN]-, [N(CN)2]-, [C(CN)3]- and [B(CN)4]-anions. Although the well-known trend regarding the surface tension decrease with the increase of the size of the aliphatic moiety at the cation was observed, the order obtained for the anions is more intricate. For a common cation and at a given temperature, the surface tension decreases according to: [N(CN)2]- > [SCN]- > [C(CN)3]- > [B(CN)4]-. Therefore, the surface tension of this homologous series does not decrease with the increase of the number of -CN groups at the anion as has been previously shown by studies performed with a more limited matrix of ILs. A maximum in the surface tension and critical temperature was observed for [N(CN)2]-based ILs. Furthermore, a minimum in the surface entropy, indicative of a highly structured surface, was found for the same class of ILs. All these evidences seem to be a result of stronger hydrogen-bonding interactions occurring in [N(CN)2]-based ILs, when compared with the remaining CN-based counterparts, and as sustained by cation-anion interaction energies derived from the Conductor Like Screening Model for Real Solvents (COSMO-RS).

4.
Fluid Phase Equilib ; 423: 190-202, 2016 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-27682333

RESUMO

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 behavior, 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, Tg. The iso-pyrrolidinium (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 the n and iso-alkyl isomers. A small increase of the surface tension was observed for the non-aromatic ILs, 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 ILs due to their higher energy barriers for shear stress.

5.
Phys Chem Chem Phys ; 17(47): 31653-31661, 2015 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-26554705

RESUMO

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.

6.
Fluid Phase Equilib ; 400: 103-113, 2015 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-26435574

RESUMO

Experimental data for density, viscosity, refractive index and surface tension of four phosphonium-based ionic liquids were measured in the temperature range between (288.15 and 353.15) K and at atmospheric pressure. The ionic liquids considered include tri(isobutyl) methylphosphonium tosylate, [P i(444)1][Tos], tri(butyl)methylphosphonium methylsulfate, [P4441][CH3SO4], tri(butyl)ethylphosphonium diethylphosphate, [P4442][(C2H5O)2PO2], and tetraoctylphosphonium bromide, [P8888][Br]. Additionally, derivative properties, such as the isobaric thermal expansion coefficient, the surface thermodynamic properties and the critical temperatures for the investigated ionic liquids were also estimated and are presented and discussed. Group contribution methods were evaluated and fitted to the density, viscosity and refractive index experimental data.

7.
Langmuir ; 30(22): 6408-18, 2014 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-24834955

RESUMO

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[(trifluoromethyl)sulfonyl]imide ([C(n)C(n)im][NTf2]) and R-alkyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([C(n)C(1)im][NTf2]), 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 [C12C12im][NTf2] or [C16C1im][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%.

8.
Fluid Phase Equilib ; 381: 36-45, 2014 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-25516634

RESUMO

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 353.15 K and at atmospheric pressure. The ILs considered include butyltrimethylammonium bis(trifluoromethylsulfonyl)imide, [N4111][NTf2], tributylmethylammonium bis(trifluoromethylsulfonyl)imide, [N4441][NTf2], diethylmethylsulfonium bis(trifluoromethylsulfonyl)imide, [S221][NTf2], and triethylsulfonium bis(trifluoromethylsulfonyl)imide, [S222][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 ILs is here discussed. 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.

9.
Carbohydr Polym ; 339: 122268, 2024 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-38823931

RESUMO

The influence of locust bean gum (LBG) galactomannans (GMs) molecular weight (Mw) to assemble microparticulate systems was evaluated, and carriers for deep lung delivery were developed. A commercial batch of LBG with a mannose/galactose (M/G) ratio of 2.4 (batch 1) was used to study the influence of different microwave partial acid hydrolysis conditions on carbohydrate composition, glycosidic linkages, and aqueous solutions viscosity. The microwave treatment did not affect the composition, presenting 4-Man (36-42 %), 4,6-Man (27-35 %), and T-Gal (24-25 %) as the main glycosidic linkages. Depolymerization led to a viscosity reduction (≤0.005 Pa·s) with no major impact on polysaccharide debranching. The structural composition of the LBG galactomannans were further elucidated with sequence-specific proteins using carbohydrate microarray technologies. A second batch of LBG (M/G 3.3) was used to study the impact of GMs with different Mw on microparticle assembling, characteristics, and insulin release kinetics. The low-Mw GMs microparticles led to a faster release (20 min) than the higher-Mw (40 min) ones, impacting the release kinetics. All microparticles exhibited a safety profile to cells of the respiratory tract. However, only the higher-Mw GMs allowed the assembly of microparticles with sizes suitable for this type of administration.


Assuntos
Galactose , Mananas , Peso Molecular , Gomas Vegetais , Mananas/química , Galactose/química , Galactose/análogos & derivados , Gomas Vegetais/química , Humanos , Pulmão/metabolismo , Portadores de Fármacos/química , Tamanho da Partícula , Viscosidade , Insulina/química , Insulina/administração & dosagem , Liberação Controlada de Fármacos , Galactanos/química , Manose/química , Animais
10.
Foods ; 12(19)2023 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-37835293

RESUMO

Dairy cream, a common ingredient in various dishes and food products, is susceptible to rapid microbial growth due to its high water activity (≈0.97) and pH (≈6.7). Thus, it requires proper processing conditions to ensure food safety and extend shelf life. High-pressure processing (HPP) has emerged as a nonthermal food pasteurization method, offering an alternative to conventional heat-based techniques to obtain tastier, fresh-like, and safe dairy products without undesirable heat-induced alterations. This study assessed the impact of HPP (450 and 600 MPa for 5 and 15 min at 7 °C) and thermal pasteurization (75 °C for 15 s) on the microbiological and physicochemical attributes of dairy cream immediately after processing and throughout refrigerated storage (4 °C). HPP-treated samples remained microbiologically acceptable even on the 51st day of storage, unlike thermally pasteurized samples. Moreover, HPP decreased inoculated Escherichia coli and Listeria innocua counts by more than 6 log units to undetectable levels (1.00 log CFU/mL). pH, color (maximum variation of ΔE* up to 8.43), and fatty acid profiles remained relatively stable under varying processing conditions and during storage. However, viscosity exhibited higher values for HPP-treated samples (0.028 ± 0.003 Pa·s) compared to thermally processed ones (0.016 ± 0.002 Pa·s) by the 28th day of storage. Furthermore, volatile compounds (VOCs) of all treated samples presented a tendency to increase throughout storage, particularly acids and aliphatic hydrocarbons. These findings show HPP's potential to significantly extend the shelf life of highly perishable dairy cream by at least 15 days compared to thermal pasteurization.

11.
J Food Sci ; 88(1): 391-402, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36463414

RESUMO

The changes in microbiological, physiochemical, and textural properties in fresh cheeses made from either cow or goat milk were observed under hyperbaric storage (HS, 50-100 MPa) at room temperature (RT) and compared with refrigerated storage under normal atmospheric pressure for 60 days. An initial microbial growth inhibition was observed for both cheese types, as well as a considerable inactivation of all endogenous microbiota under HS/RT (75-100 MPa/RT). This contributed to a higher stability of pH and color values, especially at the higher pressure at room temperature (100 MPa/RT) throughout 60 days storage. A compression effect occurred during HS/RT, resulting in higher whey loss, reduction in moisture content, and textural changes. Such changes tended to decrease over time, to values closer to the initial ones, with hardness values at the 60th day of storage at 75/RT similar to those observed for refrigeration on the 7th day and 1.4-fold higher than those observed at 100/RT. Overall, HS/RT reduced the microbial populations load during storage (≥5 log units in some cases), with minimal effects on most of the evaluated quality parameters. These results point to a considerable shelf-life extension of HS fresh cheeses, without temperature control, pinpointing HS as a more sustainable preservation strategy than refrigeration, with great potential for industrial application. PRACTICAL APPLICATION: The results presented in this study point to increased microbial stability of fresh cheeses when stored under hyperbaric storage without temperature control, leading possibly to an increased shelf-life, of up to 60 days. This kind of new food preservation strategy may be suitable for longer transportation of foods, where energy may not be handily and widely available, while additionally contributing to increased shelf-life and safety. Also, hyperbaric storage could be applied throughout the food storage, improving shelf-life with a lower carbon footprint than refrigeration.


Assuntos
Queijo , Temperatura , Armazenamento de Alimentos/métodos , Conservação de Alimentos/métodos , Refrigeração/métodos
12.
Foods ; 12(10)2023 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-37238753

RESUMO

Serra da Estrela cheese with a Protected Designation of Origin (PDO) is a traditional cheese that is wrapped in paper without vacuum. High-pressure processing (HPP), which requires vacuum packaging of the cheese, has been used for its cold pasteurization to overcome safety issues. In this study, two packaging systems were studied: non-vacuum greaseproof paper wrapping package and vacuum packaging in plastic film. Lactococci, lactobacilli, enterococci, and total mesophiles reached ca. 8 log cfu g-1 and 4-6 log cfu g-1 in control (unpasteurized) and HPP-treated cheeses, respectively, with no significant differences between packaging systems. Spoilage microorganisms' viable cell numbers were reduced to <3 log cfu g-1 (quantification limit) in HPP-treated cheeses, independently of the packaging system. Yeasts and molds reached >5 log cfu g-1 in non-vacuum paper-wrapped cheeses. A vacuum-packaging system enabled better control of cheese proteolysis, which was revealed to be closer to that of the original control cheese values at the end of the 10-month storage period. In addition, cheese stored under vacuum film packaging became harder than non-vacuum paper-wrapped cheeses at each time point. Overall, conventional non-vacuum paper wrapping is adequate for short storage periods (<3 months), but for long periods vacuum packaging in plastic film is preferable.

13.
Foods ; 12(13)2023 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-37444197

RESUMO

As an alternative to commercial whole egg thermal pasteurization (TP), the sequential combination of moderate pressure (MP) and/or ultrasound (US) pre-treatments prior to a shorter TP was evaluated. The use of US alone or in combination with MP or TP resulted in an inactivation that was far from that of commercial TP. Nevertheless, when these three technologies were combined (MP-US-TP, 160 MPa/5 min-50% amplitude/1 min-60 °C/1.75 min), a safety level comparable to that of commercial TP was established. This was likely due to a decrease in the thermal resistance of Salmonella Senftenberg 775/W caused by MP and US pre-treatments. Regarding liquid whole egg (LWE) properties, using raw LWE as a reference, TP and MP treatments each decreased protein solubility (7-12%), which was accompanied by a viscosity increment (41-59%), whereas the US-only and MP-US-TP treatments improved protein solubility (about 4%) and reduced viscosity (about 34%). On average, all treatments lowered the emulsifying properties of LWE by 35-63%, with the MP-US-TP treatment having a more dramatic impact than commercial TP. In addition, the US-only, MP-only, and MP-US-TP treatments had the greatest impact on the volatile profile of LWE, lowering the concentration of the total volatile components. In comparison to commercial TP, LWE treated with MP-US-TP exhibited greater protein solubility (19%), lower viscosity (56%), and comparable emulsifying stability, but with a decreased emulsifying capacity (39%) and a lower total volatile compounds content (77%). Considering that a combined treatment (MP-US-TP) is lethally equivalent to commercial TP, but the latter better retained the quality properties of raw LWE, including volatiles, the application of MP followed by US pre-treatments before a shorter TP did not demonstrate significant advantages on quality parameters in comparison to commercial TP.

14.
Sci Rep ; 11(1): 1668, 2021 01 18.
Artigo em Inglês | MEDLINE | ID: mdl-33462264

RESUMO

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.


Assuntos
Embalagem de Alimentos/métodos , Conservação de Alimentos/métodos , Carne/análise , Refrigeração/métodos , Animais , Oxirredução , Preservação Biológica/métodos , Salmo salar , Alimentos Marinhos , Temperatura , Vácuo
15.
Top Curr Chem ; 294: 129-41, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-21626751

RESUMO

Cell wall polysaccharides account for nearly one third of olive pomace dry matter produced by the environment friendly biphasic system. These polysaccharides are mainly cellulose, glucuronoxylans, and arabinan-rich pectic polysaccharides, in equivalent proportions. The structural features of pectic polysaccharides are unique concerning the arabinan moiety due to the occurrence of a beta-(1-->5)-terminally-linked arabinose residue. This odd feature tends to disappear with olive ripening and can be used as a diagnostic tool in the evaluation of the stage of ripening of this fruit, as well as a marker for the presence of olive pulp in matrices containing pectic polysaccharides samples. These pectic polysaccharides have the ability to form elastic gels with calcium. The critical gelling calcium and galacturonic acid concentrations are higher than that observed for commercial citrus low-methoxyl pectic material. Nevertheless, they present a syneresis occurring for much higher calcium concentration and, consequently, show a much larger zone in which homogeneous gels are formed. In addition, olive pomace pectic polysaccharides gels are more resistant to temperature than the low-methoxyl pectin/calcium gels. These properties show that olive pomace can be a potential source of gelling pectic material with useful properties for particular applications.

16.
J Nanosci Nanotechnol ; 10(4): 2816-25, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20355507

RESUMO

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.

17.
Food Res Int ; 127: 108740, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31882080

RESUMO

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.


Assuntos
Embalagem de Alimentos , Conservação de Alimentos/métodos , Armazenamento de Alimentos , Lipídeos/química , Carne/análise , Animais , Salmo salar , Fatores de Tempo , Vácuo , Compostos Orgânicos Voláteis
18.
Front Cell Dev Biol ; 8: 678, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32903827

RESUMO

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.

19.
Int J Biol Macromol ; 163: 251-259, 2020 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-32615230

RESUMO

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.


Assuntos
Filmes Comestíveis , Óleos de Plantas/química , Solanum tuberosum/química , Amido/química , Ceras/química , Amilopectina/química , Amilose/química , Fenômenos Químicos , Interações Hidrofóbicas e Hidrofílicas , Microscopia de Força Atômica , Tamanho da Partícula , Solubilidade
20.
Food Chem ; 294: 216-223, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31126456

RESUMO

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.


Assuntos
Géis/química , Polissacarídeos/química , Hidrolisados de Proteína/química , Proteínas de Soja/química , Emulsões/química , Peso Molecular , Solubilidade , Proteínas de Soja/metabolismo
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