Browsing by Autor "Catalina Fuentes"

Now showing 1 - 9 of 9

Application of asymmetric flow field-flow fractionation (AF4) and multiangle light scattering (MALS) for the evaluation of changes in the product molar mass during PVP-b-PAMPS synthesis
(Springer Science+Business Media, 2018) Catalina Fuentes; Joel Castillo; José Vila; Lars Nilsson
Characterization of molecular properties of wheat starch from three different types of breads using asymmetric flow field-flow fractionation (AF4)
(Elsevier BV, 2019) Catalina Fuentes; Rossio Castañeda; Fanny Rengel; J. Mauricio Peñarrieta; Lars Nilsson
Characterization of non-solvent precipitated starch using asymmetrical flow field-flow fractionation coupled with multiple detectors
(Elsevier BV, 2018) Catalina Fuentes; Hisfazilah Saari; Jaeyeong Choi; Seungho Lee; Malin Sjöö; Marie Wahlgren; Lars Nilsson
Co-elution phenomena in polymer mixtures studied by asymmetric flow field-flow fractionation
(Elsevier BV, 2017) Claudia Zielke; Catalina Fuentes; Lennart Piculell; Lars Nilsson
Comparison between conventional and frit-inlet channels in separation of biopolymers by asymmetric flow field-flow fractionation
(Royal Society of Chemistry, 2019) Catalina Fuentes; Jaeyeong Choi; Claudia Zielke; J. Mauricio Peñarrieta; Seungho Lee; Lars Nilsson
Asymmetric flow field-flow fractionation (AF4) is a separation technique in which a focusing/relaxation step is used after the sample is injected onto the separation channel. During the focusing/relaxation step, the sample is focused by two counter-directed flows. This allows sample components to establish a diffusion-dependent equilibrium concentration profile. The focusing step may, in some cases, cause a loss of sample due to adsorption into the accumulation wall (i.e. the membrane) or due to aggregation of the sample. In addition, the increase in sample concentration during the focusing step may prevent complete relaxation and cause overloading effects. In this study, a modified AF4 channel equipped with a frit inlet (FI-AF4) is utilized, where the sample is relaxed hydrodynamically as it enters to the channel through the frit. The main advantage of the FI-AF4 channel is to omit the focusing step. The FI-AF4 channel could also allow higher injection mass than in a conventional channel while still avoiding overloading. The purpose of the present study is to compare two channels (conventional and FI-AF4 channels) in terms of the plate height (H), resolution (Rs) and the mass recovery for analysis of a mixture of glycogen and pullulan. In addition, waxy maize (WM) starch was used to compare the mass overloading of the two channels. The results show that the type of relaxation method (i.e. focusing or hydrodynamic relaxation) had no significant effect on mass recovery. The resolution (Rs), was higher in the conventional AF4 channel than in the FI-AF4 channel for the separation of glycogen and pullulan. The results also show that it was possible to inject a higher mass of WM starch (i.e. twice the mass) onto the FI-AF4 channel, compared to a conventional AF4 channel, without observing an overloading effect.
Fractionation and characterization of starch granules using field-flow fractionation (FFF) and differential scanning calorimetry (DSC)
(Springer Science+Business Media, 2019) Catalina Fuentes; In Byeong Kang; Jangjae Lee; Dongsup Song; Malin Sjöö; Jaeyeong Choi; Seungho Lee; Lars Nilsson
Starch is one of the main carbohydrates in food; it is formed by two polysaccharides: amylose and amylopectin. The granule size of starch varies with different botanical origins and ranges from less than 1 μm to more than 100 μm. Some physicochemical and functional properties vary with the size of the granule, which makes it of great interest to find an efficient and accurate size-based separation method. In this study, the full-feed depletion mode of split-flow thin cell fractionation (FFD-SF) was employed for a size-based fractionation of two types of starch granules (corn and potato) on a large scale. The fractionation efficiency (FE) of fraction-a for corn and potato granules was 98.4 and 99.4%, respectively. The FFD-SF fractions were analyzed using optical microscopy (OM) and gravitational field-flow fractionation (GrFFF). The respective size distribution results were in close agreement for the corn starch fractions, while they were slightly different for the potato starch fractions. The thermal properties of FFD-SF fractions were analyzed, and the results for the potato starch showed that the peak temperature of gelatinization (Tp) slightly decreases as the size of the granules increases. Additionally, the enthalpy of gelatinization (ΔH) increases when the granule size increases and shows negative correlation with the gelatinization range (ΔT).
LA COMPRENSIÓN DEL TEXTO LITERARIO Y SU CONTRIBUCIÓN AL DESARROLLO EN ESCOLARES DEL SEGUNDO MOMENTO
(2018) Catalina Fuentes; C. Aileen Díaz Bernal; C. Bárbara Zenaida Pérez Pérez
La ensenanza primaria, en el pais, se encuentra inmersa en el Tercer Perfeccionamiento del Sistema Nacional de Educacion, con una serie de transformaciones que constituyen condiciones favorables para conducir un proceso de ensenanza - aprendizajecon mayor calidad. En relacion con la lengua espanola, se trata de perfeccionar cada vez mas el trabajo con la comprension textual, desde las diferentes asignaturas del curriculo. En el articulo, las autoras persiguen como objetivo reflexionar y sensibilizar a los docentes en cuanto a la necesidad que tienen de conocer la comprension del texto literario y su contribucion en el desarrollo de los escolares del segundo momento del desarrollo en la escuela primaria.
Physicochemical and structural properties of starch from five Andean crops grown in Bolivia
(Elsevier BV, 2018) Catalina Fuentes; Daysi Perez‐Rea; Björn Bergenståhl; Sergio Carballo; Malin Sjöö; Lars Nilsson
The effect of baking and enzymatic treatment on the structural properties of wheat starch
(Elsevier BV, 2016) Catalina Fuentes; Claudia Zielke; Manish Prakash; P. K. V. Kumar; J. Mauricio Peñarrieta; Ann‐Charlotte Eliasson; Lars Nilsson