Browsing by Author "Troncoso, E."

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    Adenosine mediates transforming growth factor-beta 1 release in kidney glomeruli of diabetic rats
    (WILEY, 2009) Roa, H.; Gajardo, C.; Troncoso, E.; Fuentealba, V.; Escudero, C.; Yanez, A.; Sobrevia, L.; Pastor Anglada, M.; Quezada, C.; San Martin, R.
    Up regulation of the transforming growth factor-beta 1 (TGF-beta 1) axis has been recognized as a pathogenic event for progression of glomerulosclerosis in diabetic nephropathy. We demonstrate that glomeruli isolated from diabetic rats accumulate up to sixfold more extracellular adenosine than normal rats. Both decreased nucleoside uptake activity by the equilibrative nucleoside transporter 1 and increased AMP hydrolysis contribute to raise extracellular adenosine. Ex vivo assays indicate that activation of the low affinity adenosine A(2B) receptor subtype (A(2B)AR) mediates TGF-beta 1 release from glomeruli of diabetic rats, a pathogenic event that could support progression of glomerulopathy when the bioavailability of adenosine is increased. (C) 2009 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.
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    Comparative study of physical and sensory properties of pre-treated potato slices during vacuum and atmospheric frying
    (ELSEVIER, 2009) Troncoso, E.; Pedreschi, F.; Zuniga, R. N.
    The objective of this research was to study the effect of different processing conditions on physical and sensory properties of potato chips. Potato slices of Desiree and Panda varieties (diameter: 30 mm; thickness: 3 mm) were pre-treated in the following ways: (i) control or unblanched slices without pre-drying; (ii) blanched slices in hot water at 85 degrees C for 3.5 min and air-dried at 60 degrees C until a final moisture content of similar to 0.6 kg water/kg dry solid; (iii) control slices soaked in a 3.5 kg/m(3) sodium metabisulphite solution at 20 degrees C for 3 min and pH adjusted to 3. Pre-treated slices were fried at 120 and 140 degrees C under vacuum conditions (5.37 kPa, absolute pressure) and under atmospheric pressure until they reached a final moisture content of similar to 1.8 kg water/100 kg (wet basis). An experimental design (3 x 2(3)) was used to analyze the effect of pre-treatment, potato variety, type of frying and frying temperature over the following responses: oil content, instrumental color and texture and sensory evaluation. Vacuum frying increased significantly (p < 0.05) oil content and decreased instrumental color and textural parameters. Sensory attributes, flavor quality and overall quality, were significantly improved using vacuum frying. The higher frying temperature (140 degrees C) increased Delta E, maximum breaking force, hardness and crispness and decreased L* and b* values. On the other hand, Panda potato variety improved the color of the product. A great improvement on color parameters was obtained using sulphited potato slices instead of the other pre-treatments. Although, the better flavor was obtained for control potato chips, no significant differences were found for overall quality between control and sulphited potato chips. Significant correlations (p < 0.01) between sensory and instrumental responses were found. (C) 2008 Swiss Society of Food Science and Technology. Published by Elsevier Ltd. All rights reserved.
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    Microstructure analysis on pre-treated apple slices and its effect on water release during air drying
    (ELSEVIER SCI LTD, 2011) Ramirez, C.; Troncoso, E.; Munoz, J.; Aguilera, J. M.
    Microstructural studies have played an important role in the comprehensive understanding of some food phenomena that occur during drying processes. The aim of this work was to study the effect of four pre-treatments (immersion in boiling water, vacuum impregnation, freezing/thawing, and uni-axial compression) on apple microstructure characterized by cell cavities size parameter and how the changes induced by these pre-treatments can affect the water loss rate during air drying. The quantitative structure analysis showed that freezing/thawing and compression pre-treatments caused more damage on the apple structure, yielding larger cell cavities in comparison to vacuum impregnation and immersion in boiling water and control. Apple slices that were frozen/thawed, compressed and immersed in boiling water displayed the higher drying rates and diffusivity coefficients than the vacuum impregnated and control samples. These results allow concluding that disruption of the cell walls can be considered as a factor that affects the drying rate. (C) 2011 Elsevier Ltd. All rights reserved.