Browsing by Author "Torres, Jose D."

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    Non-invasive microstructural characterization and in vivo glycemic response of white bread formulated with soluble dietary fiber
    (2024) Torres, Jose D.; Dueik, Veronica; Carre, David; Contardo, Ingrid; Bouchon, Pedro
    The global prevalence of diet-related chronic diseases, such as obesity and type 2 diabetes, has prompted the development of starchy foods with functional ingredients to control starch digestibility and promote health benefits. This study aimed to analyze the effect of a mixture of soluble dietary fibers (SDF) - inulin and methylcellulose - on microstructural changes, in vitro starch digestibility, and in vivo glycemic response of a wheat bread formulation. Quantitative micro-CT image analysis revealed a reduced bread porosity, increased pores with small diameters, and a significant rise in bread structure thickness (p < 0.05), indicating a more homogeneous and compact structure after adding the SDF blend. The addition of the SDF blend led to a reduction in in vitro starch digestibility in the bread. The rapidly available glucose decreased from 31.02 g/100 g to 11.52 g/100 g, and the unavailable glucose fraction increased from 62.81 g/100 g to 80.49 g/100 g in bread + SDF compared to regular bread (p < 0.05). These differences could be attributed to the observed fiber coating over the starchgluten network in these samples, which may act as a physical barrier, impeding starch digestibility. In line with these findings, the SDF blend significantly reduced the postprandial glycemic response of bread by up to 25% compared with Trutol (R) standard commercial glucose (p < 0.05). The new formulation could be classified as an intermediate glycemic food, as glycemic index and glycemic load were 56.43 and 15.11, respectively, which may be helpful for people who want to manage the glucose levels in their daily diets.
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    OPTIMIZATION OF VACUUM FRYING CONDITIONS OF EGGPLANT (Solanum melongena L.) SLICES BY RESPONSE SURFACE METHODOLOGY
    (2017) Torres, Jose D.; Alvis, Armando; Acevedo, Diofanor; Montero, Piedad M.; Tirado, Diego F.
    Due to the global trend to consume low-fat products, efforts are being made to reduce oil uptake in fried products. In this paper, the effect of pretreatments and parameters of the vacuum frying process on quality attributes of purple creole eggplant slices is presented. A lab-scale vacuum fryer was used to perform vacuum frying at a maximum pressure of 30kPa. Numerical optimization was carried out using the response surface methodology (RSM) through a randomized Box-Behnken experimental design, with three factors: frying temperature (120, 130 and 140 degrees C), frying time (120, 210, and 300s) and pretreatment (control, blanching and drying), which were established through preliminary tests. Moisture content and luminance (L*) decreased with increasing temperature and frying time in all processed samples. Oil uptake, color change (Delta E) and breaking force increased significantly with the increase of these same factors. The highest desirability (0.73) was obtained in blanched samples treated at 130 degrees C during 210s. The optimum values in responses were: moisture 64.77%, oil 3.89%, Delta E 16.67, luminosity 82.59, breaking force 0.96N, color 4.65, odor 4.06, taste 4.25 and greasiness 4.35. The correlation coefficients R-2 for the response variables indicated a good fit of the data to second-order regression models. Vacuum frying is an alternative to process eggplant slices with low-oil content and high acceptability.