Browsing by Author "Bouchon, Pedro "

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    Effect of Extrusion Temperature and Feed Moisture Content on the Microstructural Properties of Rice-Flour Pellets and Their Impact on the Expanded Product
    (2022) Zambrano, Yadira ; Contardo, Ingrid ; Moreno, María Carolina ; Bouchon, Pedro
    Extrusion can lead to an expanded product or to a slightly expanded pellet, known as a third-generation (3G) snack. In this case, expansion occurs subsequently, in an independent thermal device (e.g., oven), out of the extruded pellet. During both processes, several structural changes occur which are linked to processing conditions, including cooking temperature, screw speed, formulation, and initial moisture content. However, a clear relationship between processing variables and the structure of pellets and expanded products has not yet been identified. Accordingly, this work aimed to study the effect of extrusion temperature (110, 135, and 150 degrees C) and moisture content (27, 29, and 31%) in rice-flour pellets and their microwave expansion, through a microstructural approach using micro-CT. The results showed that the lowest moisture content (27%) and the highest extrusion temperature (150 degrees C) led to the highest pellet volume and the highest wall thickness, which in turn led to the highest expansion after microwave heating (50 s, 800 W). Interestingly, no significant differences were observed when analyzing the ratio between the volume of the expanded products and the volume of the pellet (~2.4) when using the different processing conditions.
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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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    Understanding the physical breakdown and catechin bioaccessibility of third generation extruded snacks enriched with catechin using the human gastric simulator
    (2024) Zambrano, Yadira; Bornhorst, Gail M.; Bouchon, Pedro
    The nutritional quality of third-generation snacks prepared from rice flour by extrusion can be improved by the addition of polyphenols such as catechins, which are known to be more stable at high temperatures. However, the extrusion parameters can impact the breakdown and release of bioactive compounds and decrease the catechin bioaccessibility. Accordingly, this study investigated the impact of different extrusion parameters, including different extrusion temperatures (110, 135, and 150 degrees C) and moisture content prior to extrusion (27 and 31%), on the breakdown and bioaccessibility of catechin-enriched snacks during in vitro dynamic digestion using the Human Gastric Simulator (HGS). The extrusion parameters did not significantly impact most measured variables by themselves, indicating that within the tested ranges, any of the processing conditions could be used to produce a product with similar digestive behavior. However, the interaction of extrusion parameters (temperature and moisture content) played a significant role in the snack behavior during digestion. For example, the combination of 27% moisture content and 150 degrees C extrusion temperature had higher catechin bioaccessibility and higher starch hydrolysis than the other treatments. Overall, these findings suggest that the processing conditions of third generation snacks enriched with catechin can be optimized within certain ranges with limited modifications in the digestive properties.