Mostrando 1 - 10 Resultados de 10 Para Buscar 'Ibarz, Albert', tiempo de consulta: 0.04s Limitar resultados
1
artículo
In the manufacture of fruit juices and pulps, is of paramount importance to refer to non-enzymatic browning and rheological behavior. The non-enzymatic browning is a phenomenon of darkening of a purely chemical (Braverman, 1980), is characterized by the presence of brown polymers called melanoidins, generated by the Maillard reaction or condensation of melanoidins, the caramelization and degradation of acid ascorbic, while the rheological behavior is define as the proportion deformation of the material when exposed to shear stress (σ) caused by a rheometer (Muller, 1978; Ibarz, 2005). Modeling studies of colour formation and definition of rheological behavior, considered in this review, aimed at the conclusion of the existence of a zero kinetic and first order respectively, and the most influential factors with the reactions are mainly Maillard, temperature, amino acids presence, water ...
2
artículo
In the manufacture of fruit juices and pulps, is of paramount importance to refer to non-enzymatic browning and rheological behavior. The non-enzymatic browning is a phenomenon of darkening of a purely chemical (Braverman, 1980), is characterized by the presence of brown polymers called melanoidins, generated by the Maillard reaction or condensation of melanoidins, the caramelization and degradation of acid ascorbic, while the rheological behavior is define as the proportion deformation of the material when exposed to shear stress (σ) caused by a rheometer (Muller, 1978; Ibarz, 2005). Modeling studies of colour formation and definition of rheological behavior, considered in this review, aimed at the conclusion of the existence of a zero kinetic and first order respectively, and the most influential factors with the reactions are mainly Maillard, temperature, amino acids presence, water ...
3
artículo
In this study the influence of the addition of orange fiber in the flow behavior of orange juice was evaluated, using for this the Herschel-Bulkley model parameters. It was observed that the flow behavior of the juices changed due to the addition of fiber, from Newtonian to Pseudoplastic when its fiber content was 5% and the temperature changed from 30 °C to 20 °C, and from Pseudoplastic to Herschel-Bulkley when its fiber content was 12.5% and the temperature changed from 10 °C to 0 °C. The increase in fiber content resulted in a progressive increase of consistency and a decrease of the flow behavior index.
4
artículo
This study investigated the influence of temperature on the color development of melanoidins formed from a single combination of glucose with amino acid. The selected amino acid, commonly found in apple juice and highly reactive in the Maillard reaction, were asparagine (Asn), aspartic acid (Asp) and glutamic acid (Glu). For this, the color development was evaluated by measuring browning at 420 nm and color measurements by spectrophotometry and colorimetry methods. The effect of temperature on the color intensity, the absorption of melanoidins were also measured at different wavelengths (280, 325, 405). The value of melanoidins formed from all model systems was located on a dominant wavelength of 325 nm, the ultra violet zone of the diagram. A first-order kinetic model was applied to L* and the evolution of color difference ΔE*. In addition, a*, b* values, significantly differences were...
5
artículo
In this study the influence of the addition of orange fiber in the flow behavior of orange juice was evaluated, using for this the Herschel-Bulkley model parameters. It was observed that the flow behavior of the juices changed due to the addition of fiber, from Newtonian to Pseudoplastic when its fiber content was 5% and the temperature changed from 30 °C to 20 °C, and from Pseudoplastic to Herschel-Bulkley when its fiber content was 12.5% and the temperature changed from 10 °C to 0 °C. The increase in fiber content resulted in a progressive increase of consistency and a decrease of the flow behavior index.
6
artículo
This study investigated the influence of temperature on the color development of melanoidins formed from a single combination of glucose with amino acid. The selected amino acid, commonly found in apple juice and highly reactive in the Maillard reaction, were asparagine (Asn), aspartic acid (Asp) and glutamic acid (Glu). For this, the color development was evaluated by measuring browning at 420 nm and color measurements by spectrophotometry and colorimetry methods. The effect of temperature on the color intensity, the absorption of melanoidins were also measured at different wavelengths (280, 325, 405). The value of melanoidins formed from all model systems was located on a dominant wavelength of 325 nm, the ultra violet zone of the diagram. A first-order kinetic model was applied to L* and the evolution of color difference ΔE*. In addition, a*, b* values, significantly differences were...
7
artículo
We have studied the kinetics of the color difference and chroma in the thermal process simple pulp (16 ° Brix) and concentrate (28 °Brix) Haden handle at different temperatures, the statistical variation of the colorimetric parameters L*, AE* and ∆C* with respect to time, and results in higher activation energy analysis of the effect of temperature on the kinetic constants, leading to the conclusion that correspond to reaction kinetics zero order.
8
artículo
We have studied the kinetics of the color difference and chroma in the thermal process simple pulp (16 ° Brix) and concentrate (28 °Brix) Haden handle at different temperatures, the statistical variation of the colorimetric parameters L*, AE* and ∆C* with respect to time, and results in higher activation energy analysis of the effect of temperature on the kinetic constants, leading to the conclusion that correspond to reaction kinetics zero order.
9
artículo
This paper presents a study on kinetic and thermodynamic compensation to evaluate the kinetics of non-enzymatic browning of clarified lemon juices. In a previous work, the kinetic constants of browning were presented using the evolution of the absorbance at 420 nm (A420) and luminosity (L*) for different soluble solids contents (64.6; 50; 35; 20 and 10 ºBrix) and different working temperatures (70, 80, 90 and 95 ºC). The parameters of the Arrhenius equation were obtained by fitting the kinetic constants and temperatures. The variation of lnK0 with Ea follows a linear trend, so there is kinetic compensation, with isokinetic temperature values being 126.6 ºC and 149.7 ºC for A420 and L*, respectively. The transition state equilibrium constants were determined using the Eyring equation for each soluble solids content and each temperature. The equilibrium constants were adjusted to the V...
10
artículo
ABSTRACT Althoughknowledgeofthemicrostructureoffoodofvegetaloriginhelpsustounderstand the behavior of food materials, the variability in the microstructural elements complicates this analysis. In this regard, the construction of learning models that represent the actual microstructures of the tissue is important to extract relevant information and advance in the comprehension of such behavior. Consequently, the objective of this research is to compare two machine learning techniques—Convolutional Neural Networks (CNN) and Radial Basis Neural Networks (RBNN)— when used to enhance its microstructural analysis. Two main contributions can be highlighted from this research. First, a method is proposed to automatically analyze the microstructural elements of vegetal tissue; and second, a comparison was conducted to select a classifier to discriminate between tissue structures. For the com...