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1.
Ann Bot ; 2024 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-39021206

RESUMO

BACKGROUND: In epiphytic bromeliads, the roots used to be considered poorly functional organs in the processes of absorption and metabolization of water and nutrients, while the leaves always acted as protagonists in both functions. More recent discoveries have been changing this old view of the root system. SCOPE: In this review, we will address the old thoughts of the scientific community regarding the function performed by the roots of epiphytic bromeliads (mere holdfast structures with low physiological activity) and the importance of a reduced or lack of root system for the emergence of epiphytism. We will present indirect and direct evidence that contradicts this older hypothesis. Furthermore, the importance of the root absorptive function mainly for juvenile tankless epiphytic bromeliads and the characteristics of the root absorption process of adult epiphytic tank bromeliads will be thoroughly discussed in physiological aspects. Finally, some factors (species, substrate, environmental conditions) that influence the absorptive capability of the roots of epiphytic tank bromeliads will also be considered in this review, highlighting the importance that the absorptive role of the roots have for the plasticity of bromeliads that live on trees, which is an environment characterized by the intermittent availability of water and nutrients. CONCLUSIONS: The roots of tank-forming epiphytic bromeliads play important roles in the absorption and metabolization of nutrients and water. The importance of roots stands out mainly for juvenile tankless bromeliads since the root is the main absorptive organ. In larger plants with tank, although the leaves become the protagonists in the resource acquisition process, the roots complement the absorptive function of the leaf trichomes, resulting in a better growth of the bromeliad. The physiological and biochemical properties of the processes of absorption and distribution of resources in the tissues seem to differ between absorption by trichomes and roots.

2.
Polymers (Basel) ; 16(7)2024 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-38611183

RESUMO

The aim of this work is to analyze the effect of water absorption on the mechanical properties and damage mechanisms of polyester/glass fiber/jute fiber hybrid composites obtained using the compression molding and vacuum-assisted resin transfer molding (VARTM) techniques with different stacking sequences. For this purpose, the mechanical behavior under tensile stress of the samples was evaluated before and after hygrothermal aging at different temperatures: TA, 50 °C, and 70 °C for a period of 696 h. The damage mechanism after the mechanical tests was evaluated using SEM analysis. The results showed a tendency for the mechanical properties of the composites to decrease with exposure to an aqueous ambient, regardless of the molding technique used to conform the composites. It was also observed that the stacking sequence had no significant influence on the dry composites. However, exposure to the aqueous ambient led to a reduction in mechanical properties, both for the molding technique and the stacking sequence. Damage such as delamination, fiber pull-out, fiber/matrix detachment, voids, and matrix removal were observed in the composites in the SEM analyses.

3.
Materials (Basel) ; 17(7)2024 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-38612163

RESUMO

New composites produced with recycled waste are needed to manufacture more sustainable construction materials. This paper aimed to analyze the hygrothermal and mechanical performance of plasterboard with a polymethylhydrosiloxane (PMHS) content, incorporating recycled PET microplastic waste and varying factors such as PMHS dose, homogenization time, and drying temperature after setting. A cube-centered experimental design matrix was performed. The crystal morphology, porosity, fluidity, water absorption, flexural strength, and thermal conductivity of plasterboards were measured. The results showed that incorporating recycled PET microplastics does not produce a significant difference in the absorption and flexural strength of plasterboards. However, the addition of recycled PET reduced the thermal conductivity of plasterboards by around 10%.

4.
Materials (Basel) ; 16(18)2023 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-37763383

RESUMO

Bio-based materials, such as wood bio-concrete (WBC), hold promise in reducing energy consumption and carbon footprint of the construction industry. However, the durability of these materials is not well understood and can be negatively affected by the high water absorption capacity of wood bio-aggregates. In the field of cement composites, for example, silane-siloxane-based water repellent has been used to protect such materials from natural environmental attack. Nevertheless, there is still a limited understanding of various aspects related to this type of treatment, including its performance when applied to the bio-concrete substrate. This research aimed to investigate the influence of silane-siloxane on the rheology and hydration of cementitious paste through isothermal calorimetry and thermogravimetric analysis. Additionally, the impact of silane-siloxane on the physical and mechanical properties of WBCs was examined by conducting tests at fresh state (flow table and entrained air content) and hardened state (compressive strength and capillary water absorption). The composites were produced with a volumetric fraction of 45% of wood shavings while the cement matrix consisted of a combination of cement, rice husk ash, and fly ash. Silane-siloxane was applied in three ways: as coating, incorporated as an admixture, and in a combination of both methods. The results indicated that by incorporating silane in the cementitious pastethe viscosity increased by 40% and the hydration was delayed by approximately 6 h when compared to the reference. In addition, silane improved the compressive strength of WBCs by 24% when incorporated into the mixture, expressively reduced the water sorptivity of WBCs (93%), and was more effective if used as coating.

5.
Materials (Basel) ; 16(14)2023 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-37512358

RESUMO

Plasterboard is an important building material in the construction industry because it allows for quick installation of walls, partitions, and ceilings. Although a common material, knowledge about its performance related to modern polymers and fabrication conditions is still lacking. The present work analyzes how some manufacturing factors applied during the plaster board fabrication impact on some plasterboard properties, including water absorption, flexural strength, and thermal conductivity. The manufacturing variables evaluated are the dose (D) of polymethylhydrosiloxane (PMHS), the agitation time of the mixture (H), and the drying temperature of the plaster boards after setting (T). The results suggest that factors D, H, and T induce changes in the porosity and the morphological structure of the calcium sulfate dihydrate crystals formed. Performance is evaluated at two levels of each factor following a statistical method of factorial experimental design centered on a cube. Morphological changes in the crystals of the resulting boards were evaluated with scanning electron microscopy (SEM) and the IMAGEJ image analysis program. Porosity changes were evaluated with X-ray microcomputed tomography (XMT) and 3D image analysis tools. The length-to-width ratio of the crystals decreases as it goes from low PMHS dosage to high dosage, favoring a better compaction of the plasterboard under the right stirring time and drying temperature. In contrast, the porosity generated by the incorporation of PMHS increases when going from low-level to high-level conditions and affects the maximum size of the pores being generated, with a maximum value achieved at 0.6% dosage, 40 s, and 140 °C conditions. The presence of an optimal PMHS dosage value that is approximately 0.6-1.0% is evidenced. In fact, when comparing trails without and with PMHS addition, a 10% decrease in thermal conductivity is achieved at high H (60 s) and high T (150 °C) level conditions. Water absorption decreases by more than 90% when PMHS is added, mainly due to the hydrophobic action of the PMHS. Minimum water absorption levels can be obtained at high drying temperatures. Finally, the resistance to flexion is not affected by the addition of PMHS because apparently there are two opposing forces acting: on one hand is the decrease in the length-width ratio giving more compactness, and on the other hand is the generation of pores. The maximum resistance to flexion was found around a dosage of 0.6% PMHS. In conclusion, the results suggest that the addition of PMHS, the correct agitation time of the mixture, and the drying temperature reduce the water absorption and the thermal conductivity of the gypsum boards, with no significant changes in the flexural resistance.

6.
Int J Biol Macromol ; 242(Pt 1): 124405, 2023 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-37100327

RESUMO

The industrial residue of cashew apple juice processing (MRC) was evaluated as an alternative medium for bacterial cellulose (BC) production by Komagataeibacter xylinus ATCC 53582 and Komagataeibacter xylinus ARS B42. The synthetic Hestrin-Schramm medium (MHS) was used as a control for growing and BC production. First, BC production was assessed after 4, 6, 8, 10, and 12 days under static culture. After 12 days of cultivation, K. xylinus ATCC 53582 produced the highest BC titer in MHS (3.1 g·L-1) and MRC (3 g·L-1), while significant productivity was attained at 6 days of fermentation. To understand the effect of culture medium and fermentation time on the properties of the obtained films, BC produced at 4, 6, or 8 days were submitted to infrared spectroscopy with Fourier transform, thermogravimetry, mechanical tests, water absorption capacity, scanning electron microscopy, degree of polymerization and X-ray diffraction. The properties of BC synthesized in MRC were identical to those of BC from MHS, according to structural, physical, and thermal studies. MRC, on the other hand, allows the production of BC with a high water absorption capacity when compared to MHS. Despite the lower titer (0.88 g·L-1) achieved in MRC, the BC from K. xylinus ARS B42 presented a high thermal resistance and a remarkable absorption capacity (14664 %), suggesting that it might be used as a superabsorbent biomaterial.


Assuntos
Anacardium , Gluconacetobacter xylinus , Malus , Malus/metabolismo , Celulose/química , Fermentação , Gluconacetobacter xylinus/metabolismo , Meios de Cultura/química
7.
Materials (Basel) ; 14(17)2021 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-34501126

RESUMO

The ever-growing consumption and improper disposal of non-biodegradable plastic wastes is bringing worrisome perspectives on the lack of suitable environmentally correct solutions. Consequently, an increasing interest in the circular economy and sustainable techniques is being raised regarding the management of these wastes. The present work proposes an eco-friendly solution for the huge amount of discarded polyethylene terephthalate (PET) wastes by addition into soil-cement bricks. Room temperature molded 300 × 150 × 70 mm bricks were fabricated with mixtures of clay soil and ordinary Portland cement added with up to 30 wt.% of PET waste particles. Granulometric analysis of soil indicated it as sandy and adequate for brick fabrication. As for the PET particles, they can be considered non-plastic and sandy. The Atterberg consistency limits indicated that addition of 20 wt.% PET waste gives the highest plasticity limit of 17.3%; moreover, with PET waste addition there was an increase in the optimum moisture content for the compaction and decrease in specific weight. Standard tests showed an increase in compressive strength from 0.83 MPa for the plain soil-cement to 1.80 MPa for the 20 wt.% PET-added bricks. As for water absorption, all bricks displayed values between 15% and 16% that attended the standards and might be considered an alternative for non-structural applications, such as wall closures in building construction.

8.
Materials (Basel) ; 14(15)2021 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-34361473

RESUMO

Moisture distribution in cement-based materials is important from the durability point of view. In the present study, a portable three-magnet array with an elliptical surface radio frequency coil was used to undertake magnetic resonance measurements of moisture content in ordinary Portland cement mortar and concrete samples. Measurements along the length of the samples during capillary water absorption produced moisture content profiles that were compared with reference profiles acquired using a magnetic resonance imaging instrument. Profiles obtained with the three-magnet array were similar in shape and in penetration depth to those acquired with magnetic resonance imaging. The correlation coefficient between the moisture content measured with both techniques was r2 = 0.97. Similar values of saturated permeability of the mortars with identical w/c ratio were computed with the Hydrus 1D software based on the moisture content profiles. Additionally, inverse Laplace transformation of the signal decays provided the water-filled pore size distribution in saturated and unsaturated regions of the samples. The three-magnet array was successfully used to acquire nuclear magnetic resonance signal from a concrete sample, which was not possible with the magnetic resonance imaging instrument using the single-point imaging technique.

9.
Polymers (Basel) ; 13(5)2021 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-33671030

RESUMO

This article aims to study the non-Fickian water absorption process in vegetable fiber-reinforced polymer composite using the Langmuir-type model, evaluating the influence of mass diffusivity on the process. The numerical solutions of the governing equations were obtained using the finite-volume method. Transient results of the local and average moisture content, free and entrapped water molecules concentration considering the constant diffusivity and as a function of the average and local moisture content were presented and analyzed. It was observed that the mass diffusivity effectively influences the water absorption behavior, especially in the initial time of the process, where higher differences in the water migration rates into the material are found. The largest free and entrapped water molecule concentration gradients were found close to the composite surface, especially when considering constant mass diffusivity.

10.
Polymers (Basel) ; 12(11)2020 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-33121178

RESUMO

The purpose of this article was to theoretically study the non-Fickian moisture absorption process in vegetable-fiber-reinforced polymer composites using a Langmuir-type model. Here, the focus was on evaluating the effect of the water layer thickness that surrounds the composite during the water migration process. The solutions of the governing equations were obtained using the finite volume method, considering constant thermophysical properties and non-deformable material. The results for the local and average moisture content and concentration, gradient values, and the transient rates of the free and bound (water) molecules in the process were presented and analyzed. It was observed that the water layer thickness strongly influenced the water absorption kinetics, the moisture content gradient values, and the equilibrium moisture content inside the material. It is envisaged that this new approach will contribute to better interpretation of experimental data and a better understanding of the physical phenomenon of water absorption, which directly affects the properties of composite materials.

11.
Food Chem ; 323: 126776, 2020 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-32305806

RESUMO

The objective was to evaluate the effect of modifying okara with alkaline hydrogen peroxide at different H2O2 concentrations and treatment temperatures on its soluble fiber content, water absorption and holding capacity, swelling capacity, and protein solubility in water. Multi-response optimization and characterization of physical, chemical, and techno-functional properties of unmodified and modified okara under optimal condition were performed. Treatment under optimal condition (2% H2O2 and 42 °C for 5 h) resulted in a 601% increase in soluble fiber content, a 26% increase in water absorption and holding capacity and swelling capacity, and a 609% increase in soluble protein. Scanning electron micrographs revealed that modified okara particles had a more fragmented structure and a rougher surface than control. Alkaline hydrogen peroxide treatment altered the color, chemical composition, and techno-functional properties of okara. The modification method has potential to add value to okara and contribute to the use of agro-industrial residues.

12.
Eur Oral Res ; 54(2): 69-76, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-33474550

RESUMO

PURPOSE: This study aimed to evaluate if the contact of calcium hydroxide cements with polyacrylic and phosphoric acids would alter selected microscopic and physical and chemical properties. MATERIALS AND METHODS: Chemically activated (Hydro C and Dycal Advanced Formula II) and resin-modified photoactivated (Ultra-blend Plus) calcium hydroxide cements were examined after exposure to the following different strategies: contact with no substance (control group); rinsing with water and drying; contact with polyacrylic acid, rinsing with water, and drying; and contact with phosphoric acid, rinsing with water, and drying. Surface morphology, determined by scanning electron microscopy (SEM), water sorption and solubility, and the release of hydroxyl ions were evaluated. RESULTS: SEM showed a greater impact of the conditioning acids on the surface of the chemically activated cements. Ultra-blend Plus obtained the highest value of sorption (516.8 µg/mm3) and solubility (381.1 µg/mm3) and Hydro C had the lowest values 251.9 µg/mm3 and 206.3 µg/mm3 respectively. Considering the release of hydroxyl ions in comparison with time, Hydro C and Ultra-blend Plus presented significant statistical difference for polyacrylic and phosphoric acid subgroups. CONCLUSION: Hydro C and Dycal presented intensification of surface irregularities after contact with conditioning acids. The chemically activated materials suffered a decrease in sorption and solubility. The action of the conditioning acids promotes greater increase of the release of hydroxyl ions for Hydro C and Dycal.

13.
Protoplasma ; 257(1): 103-118, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31402407

RESUMO

The chemical composition of the cell walls strongly affects water permeability and storage in root tissues. Since epiphytic orchids live in a habitat with a highly fluctuating water supply, the root cell walls are functionally important. In the present study, we used histochemistry and immunocytochemistry techniques in order to determine the composition of the cell walls of root tissues of 18 epiphytic species belonging to seven subtribes across the Orchidaceae. The impregnation of lignin in the velamen cells reinforces its function as mechanical support and can facilitate apoplastic flow. Pectins, as well cellulose and lignins, are also essential for the stability and mechanical support of velamen cells. The exodermis and endodermis possess a suberinized lamella and often lignified walls that function as selective barriers to apoplastic flow. Various cortical parenchyma secondary wall thickenings, including phi, reticulated, and uniform, prevent the cortex from collapsing during periods of desiccation. The presence of highly methyl-esterified pectins in the cortical parenchyma facilitates the formation of gels, causing wall loosening and increased porosity, which contributes to water storage and solute transport between cells. Finally, cells with lipid or lignin impregnation in the cortical parenchyma could increase the water flow towards the stele.


Assuntos
Parede Celular/química , Orchidaceae/química , Orchidaceae/citologia , Raízes de Plantas/química , Lignina/metabolismo , Lipídeos/química , Pectinas/metabolismo
14.
Braz. arch. biol. technol ; Braz. arch. biol. technol;63: e20190538, 2020. tab, graf
Artigo em Inglês | LILACS | ID: biblio-1132222

RESUMO

Abstract Sweet orange juice is an important part of diet since it is nutritious beverage offering good taste and play significant part in a healthy diet. High hygroscopicity, thermo-plasticity and presence of low molecular weight components in sweet orange juice offer low glass transition temperature (Tg), likely to form soft particle with sticky surface leading to sticky powder during drying. Maltodextrins are amorphous drying aids that tend to inhibit sugar crystallization and form a high Tg product after drying. In this study, the effect of the different spray drying parameters on the quality of powder derived from control and concentrated juice at three inlet air temperatures 120, 130 and 140 °C and at three levels of juice total soluble solids (TSS): maltodextrin levels at 1:0.5; 1:1 and 1:1.5 were studied. The impact of inlet air temperature and maltodextrin concentration has significantly affected various properties of sweet orange powder. For control juice, process yields increased with increase in inlet air temperature and maltodextrin concentration. However, for reverse osmosis (RO) concentrate, process yield increased with increase in maltodextrin concentration and decreased with increase in inlet air temperature. For control juice, process yields obtained were in the range of 12.59-41.16% and in case of concentrated juice, the process yield obtained was in the range of 21.35-56.95% at different combinations of inlet air temperature and maltodextrin concentrations. Spray-dried powder was considered as "possible" and "fair" in terms of flowability and cohesiveness. Vitamin C retention was high at lower inlet air temperature with lower concentration of maltodextrin.


Assuntos
Polissacarídeos/farmacologia , Temperatura , Produção de Alimentos , Citrus sinensis , Sucos de Frutas e Vegetais/análise
15.
rev. udca actual. divulg. cient ; 22(2): e1183, Jul-Dic. 2019. tab, graf
Artigo em Inglês | LILACS-Express | LILACS | ID: biblio-1094803

RESUMO

ABSTRACT Amaranth flour is of high nutritional value, which makes it a potential food. Grinding of the grains is a necessary operation to obtain products with physical properties that provide the food products with adequate characteristics. To analyze the effect of grinding velocity and time on the particle diameters and physical properties of Amaranth flour by ball mill, a Doehlert design with triplicate at the central point was used. The tests were carried out with the mass ratio (balls/samples) (R1:5). Granulometry curve of each design system was fitted to the Rosin-Ramler-Bennet and Holmes-Hukki equations. A found a very significant effect of the velocity on the particle diameters (D50, D63 and D80). The flour obtained were modeled satisfactorily (r2>0.99) by using the Rosin-Ramler-Bennet equation, where the homogeneity index of (n1) was obtained, which was directly influenced by the milling energy. By using the Holmes-Hukki model, were able to model the characteristic diameters with the grinding energy; a critical region was observed between 100μm and 200μm, where lost efficiency in the size reduction. The excess energy, released in the critical region, caused the decrease in starch crystallinity and structural changes in the protein, which affect the functional properties of the flour. The planetary mill is emerging as an effective mean of modifying the functional properties in the development of new food products.


RESUMEN La harina de amaranto es de alto valor nutricional, convirtiéndola en un alimento potencial. La molienda de los granos es una operación necesaria, para brindarle a los productos alimenticios unas adecuadas propiedades físicas. Para analizar el efecto de la velocidad y el tiempo de molienda sobre el diámetro de particular y las propiedades físicas de la harina obtenida por molienda de bolas, se usó un diseño experimental Doehlert, con réplica en el punto central. En las pruebas de molinería se tuvo en cuenta la relación masa de bolas/masa de muestra (R1:5). Las curvas de granulometría de cada punto del diseño experimental fueron modeladas por las ecuaciones de Rosin-Ramler-Bennet y Holmes-Hukki. Se encontró un efecto muy significativo de la velocidad de molienda sobre los diámetros característicos (D50, D63 y D80). El modelo de Rosin-Ramler-Bennet ajustó satisfactoriamente (r2>0.99), además, se obtuvo el índice de homogeneidad (n1), el cual, fue afectado directamente por la energía de molienda. El uso del modelo de Holmes-Hukki permitió relacionar el diámetro de partícula con la energía de molienda y se logró observar una región crítica entre 100μm y 200μm, donde hay una reducción en la eficiencia de la reducción de tamaño de partícula. El exceso de energía liberada en la región crítica causó el descenso en la cristalinidad del almidón y provocó cambios en la estructura de las proteínas, lo cual, modificó las propiedades físicas de la harina. El Molino planetario es una técnica emergente y efectiva para modificar las propiedades funcionales en el desarrollo de nuevo productos alimenticios.

16.
Carbohydr Polym ; 205: 106-116, 2019 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-30446085

RESUMO

Hydrogels are three-dimensional, hydrophilic networks, comprising polymeric chains linked through physical or chemical bonds. In the area of food, hydrogels have great potential to be used in food packaging systems or as carriers of bioactive components. This paper reviews the nature of hydrogels, their 3D network conformation, their functional properties, and their potential applications in food packaging systems. Regarding their potential food packaging applications, hydrogels can present a conformation which allows their use as part of a packaging system to control the humidity generated by food products with high water content. Moreover, the incorporation of nanoparticles into hydrogels may grant them antimicrobial activity. Finally, although the current research in this field is still limited, the results obtained so far are promising for innovative and potential applications in the food field, which also include their integration into intelligent food packaging systems and their direct incorporation into food matrices as a flavor carrier system.

17.
Ciênc. rural ; Ciênc. rural (Online);46(3): 573-579, mar. 2016. tab, graf
Artigo em Inglês | LILACS | ID: lil-769678

RESUMO

ABSTRACT: The current research aimed to evaluate the effects of extrusion parameters on the physical characteristics of extruded blends of cassava leaf flour and starch. A factorial central composite design with four independent variables and the response surface methodology were used to evaluate the results of color parameters (L*, a*, b*), water absorption index, water solubility index and paste properties, according to the variations in the leaf flour percentage (1.5 to 7.5%), extrusion temperature (60 to 100ºC), screw speed (175 to 231rpm) and moisture (20 to 30%). Extrusion conditions affect color, water absorption and water solubility indexes and paste properties of blends. The intermediate tested conditions of variable parameters lead to obtain extruded products with higher cold viscosity and water absorption index and light color, desirable qualities for rapid preparation products.


RESUMO: Este trabalho teve por objetivo avaliar os efeitos dos parâmetros de extrusão sobre as características físicas de misturas extrusadas de farinha de folhas de mandioca e amido. O delineamento central composto rotacional, com quatro variáveis independentes, e a metodologia de superfície de resposta foram utilizados para avaliar os resultados dos parâmetros de cor (L*, a*, b*), índice de absorção de água, índice de solubilidade em água e propriedades de pasta, de acordo com as variações da percentagem de farinha de folha (1,5 a 7,5%), da temperatura de extrusão (60 a 100ºC), da rotação da rosca (175-231rpm) e da umidade (20 a 30%). As condições do processo de extrusão afetaram a cor, os índices de absorção de água e solubilidade em água e as propriedades de pasta das misturas. As intermediárias testadas dos parâmetros variáveis levaram à obtenção de produtos extrusados com maior viscosidade fria e índice de absorção de água e de cor clara, qualidades desejáveis para produtos de preparação rápida.

18.
Ci. Rural ; 46(3): 573-579, Mar. 2016. tab, graf
Artigo em Inglês | VETINDEX | ID: vti-27689

RESUMO

The current research aimed to evaluate the effects of extrusion parameters on the physical characteristics of extruded blends of cassava leaf flour and starch. A factorial central composite design with four independent variables and the response surface methodology were used to evaluate the results of color parameters (L*, a*, b*), water absorption index, water solubility index and paste properties, according to the variations in the leaf flour percentage (1.5 to 7.5%), extrusion temperature (60 to 100ºC), screw speed (175 to 231rpm) and moisture (20 to 30%). Extrusion conditions affect color, water absorption and water solubility indexes and paste properties of blends. The intermediate tested conditions of variable parameters lead to obtain extruded products with higher cold viscosity and water absorption index and light color, desirable qualities for rapid preparation products.(AU)


Este trabalho teve por objetivo avaliar os efeitos dos parâmetros de extrusão sobre as características físicas de misturas extrusadas de farinha de folhas de mandioca e amido. O delineamento central composto rotacional, com quatro variáveis independentes, e a metodologia de superfície de resposta foram utilizados para avaliar os resultados dos parâmetros de cor (L*, a*, b*), índice de absorção de água, índice de solubilidade em água e propriedades de pasta, de acordo com as variações da percentagem de farinha de folha (1,5 a 7,5%), da temperatura de extrusão (60 a 100ºC), da rotação da rosca (175-231rpm) e da umidade (20 a 30%). As condições do processo de extrusão afetaram a cor, os índices de absorção de água e solubilidade em água e as propriedades de pasta das misturas. As intermediárias testadas dos parâmetros variáveis levaram à obtenção de produtos extrusados com maior viscosidade fria e índice de absorção de água e de cor clara, qualidades desejáveis para produtos de preparação rápida.(AU)


Assuntos
Manihot , Misturas Alimentícias , Amido
19.
Rev. bras. ciênc. avic ; 18(1): 193-196, jan.-mar. 2016. tab, graf
Artigo em Inglês | VETINDEX | ID: biblio-1490247

RESUMO

This study aimed at evaluating the levels of moisture, protein, water to protein ratio, and water absorption during chilling of chicken giblets (heart, liver, and gizzard) to set legal limits of water absorption during this process. The survey was conducted in the southern Brazil, the largest broiler-producing region of this country. Giblets (heart, liver, and gizzard) were collected fresh from the processing line after evisceration and at the exit of the chiller after the immersion process from two processing plants. One of the plants (PP1) processes small chickens (1,100g live weight) and PP2 processes chickens with 2,800g live weight. In total, 448 samples were collected. Laboratory tests were performed in duplicate for each parameter measured. The results show that moisture levels of fresh giblets were higher in the gizzard, followed by the liver and the heart, whereas in chilled giblets, the gizzard still maintained the highest moisture level, but was followed by the heart and then the liver. Both in fresh and chilled samples, the liver presented the highest protein content, followed by the gizzard and the heart. Water to protein ratios were higher in chilled than in fresh samples, and was highest in the heart, followed by the gizzard and the liver. After immersion in the chiller, the heart presented the highest water absorption rate (6.59%), which was significantly higher compared with those of the liver (4.16%) and the gizzard (4.51%). Considering that the water absorption rates obtained both in fresh and chilled chicken giblets were below 8.00%, the following upper limits of water absorption are suggested for chicken giblet processing in Brazil: 7.0% for the heart, and 5.0% for the gizzard and the liver.


Assuntos
Animais , Galinhas/fisiologia , Galinhas/metabolismo , Ingestão de Líquidos/fisiologia , Umidade
20.
Rev. bras. ciênc. avic ; 18(2): 299-302, apr.-jun. 2016. tab
Artigo em Inglês | VETINDEX | ID: biblio-1490258

RESUMO

The objectives of the present study were to evaluate the water and protein contents and the water-to-protein ratio of chicken parts before and after the pre-chilling process, to compare these results with the values officially recommended by the Brazilian Ministry of Agriculture, and to evaluate the effect of genetic strain and sex on these parameters. Water (%) and protein (%) contents, and water-to-protein ratio (WPR) of boneless and skinless breast (FILLETS) and breast with bone and skin (BREAST) were determined before (BPC) and after (APC) carcass pre-chilling. A total of 585 samples were evaluated: 221 fillets/male, 216 breasts/male, 76 fillets/female, and 72 fillets/female of four different broilers strains were evaluated before (BPC) and after (APC) samples. Water and protein contents and water-to-protein ratio were determined according to the Brazilian legislation. Results showed that there were no significant differences between genetic strains (p 0.05) neither in samples collected before or after the chiller. There were no statistical differences in the parameters studied among genetic strains. However, a high percentage of male breast samples presented water level and water-to-protein ratio above the official limits already before pre-chilling.


Assuntos
Animais , Análise para Determinação do Sexo/instrumentação , Análise para Determinação do Sexo/veterinária , Comportamento de Ingestão de Líquido/fisiologia , Galinhas/anatomia & histologia , Galinhas/genética , Galinhas/metabolismo , Galinhas/fisiologia
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