Browsing by Author "Contardo, Ingrid"

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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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    Impact of homolactic fermentation using Lactobacillus acidophilus on plant-based protein hydrolysis in quinoa and chickpea flour blended beverages
    (2025) Hurtado-Murillo, John; Franco, Wendy; Contardo, Ingrid
    In this study, three beverages formulated with quinoa and chickpea flour blends were fermented using Lactobacillus acidophilus LA-5 to assess the effect of lactic acid fermentation on the degree of hydrolysis of plant-based proteins. Additionally, the impact of quinoa and chickpea blends on the protein content and protein solubility in the beverages was evaluated. Fermentation was completed within 10 h, resulting in a decrease in the pH (<4.3) and an increase in titratable acidity and lactic acid (>0.37 % and > 1.7 g/L), respectively. SDS-PAGE and the Ophthalaldehyde method revealed hydrolysis of quinoa and chickpea proteins. A quinoa-to-chickpea ratio of 50 % exhibited the highest protein content (>2 %), solubility (43.6 %), and hydrolysis (35.9 %) after fermentation, indicating that an increase in chickpea improved these parameters in the prepared PBBs. Overall, fermentation using Lactobacillus acidophilus increased plant protein hydrolysis, and legume addition improved the protein content and the nutritional value of plant-based beverages.
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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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    Relationship between microstructure formation and in vitro starch digestibility in baked gluten-starch matrices
    (2024) Torres, José D.; Dueik, Verónica; Contardo, Ingrid; Carré, David; Bouchon Aguirre, Pedro Alejandro
    Increased prevalence of diabetes prompts the development of foods with reduced starch digestibility. This study analyzed the impact of adding soluble dietary fiber (inulin-IN; polydextrose-PD) to baked gluten-starch matrices (7.5–13%) on microstructure formation and in vitro starch digestibility. IN and PD enhanced water-holding capacity, the hardness of baked matrices, and lowered water activity in the formulated matrices, potentially explaining the reduced starch gelatinization degree as IN or PD concentration increased. A maximum gelatinization decrease (26%) occurred in formulations with 13% IN. Micro-CT analysis showed a reduction in total and open porosity, which, along with the lower gelatinization degree, may account for the reduced in vitro starch digestibility. Samples with 13% IN exhibited a significantly lower rapidly available glucose fraction (8.56 g/100 g) and higher unavailable glucose fraction (87.76 g/100 g) compared to the control (34.85 g/100 g and 47.59 g/100 g, respectively). These findings suggest the potential for developing healthier, starch-rich baked foods with a reduced glycemic impact.
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    Role of Quinoa (Chenopodium quinoa Willd) and Chickpea (Cicer arietinum L.) Ratio in Physicochemical Stability and Microbiological Quality of Fermented Plant-Based Beverages during Storage
    (2024) Hurtado-Murillo, John; Franco, Wendy; Contardo, Ingrid
    Three different fermented plant-based beverages were prepared and stored for a long period (50 days) to assess the effect of the quinoa-to-chickpea ratio on physicochemical stability and microbiological quality. Physicochemical stability was evaluated based on pH, acidity, Brix degrees, water-holding capacity (WHC), viscosity, and viscoelasticity. At the end of the long-term storage period, the pH, acidity, and WHC remained stable. During the entire storage period, the beverages maintained good bacterial, fungal, and lactic acid bacteria (LAB) counts. Quinoa and chickpea flour ratios of 50% showed a higher viscosity (18 Pa.s) and WHC (65%) during short-term storage (0-30 d), indicating that the presence of chickpea flour had a positive effect on these parameters, possibly because chickpea starch contains higher amounts of amylose and long-branch chain amylopectin, which impacts the retrogradation pattern under acidic and refrigerated conditions. However, at the end of storage (50 days), the same blend had a higher acidity, lower viscosity (0.78 Pa.s), and lower LAB counts (similar to 1 x 10(8) CFU/mL), indicating that the increase in chickpea flour had an adverse long-term effect on these parameters. These results suggest that although different ratios of plant sources can improve the physical aspects, they need to be incorporated in a balanced manner to avoid negative effects on both short- and long-term storage, owing to the incorporation of different types of starches and proteins affecting the stability of the system.
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    Tailoring Rheological, Viscoelastic, and Starch Structural Properties in Plant-Based Beverages via Homolactic Fermentation of Quinoa and Chickpea Flour Blends
    (2025) Hurtado Murillo, John; Franco, Wendy; Contardo, Ingrid
    This study investigated the effects of homolactic fermentation on the rheological, viscoelastic, and starch structural properties of quinoa–chickpea flour-based beverages. Three formulations with increasing proportions of chickpea flour (10, 25, and 50%) were fermented for 10 h with Lactobacillus acidophilus LA-5. Apparent viscosity, deformation capacity, storage modulus (G′), and pasting behavior were measured along with FTIR-based analysis of the starch molecular structure. All fermented samples reached pH values < 4.5 and exhibited improved rheological properties with significant increases in viscosity and storage modulus (G′), particularly in the 50:50 blend. These enhancements were attributed to the synergistic effects of homolactic fermentation and inherent properties of chickpea starch, particularly its high amylose content, large granule size, and long amylopectin chains. FTIR analysis revealed that the short-range molecular order of starches was preserved after fermentation in all beverages, except for the 50:50 blend, as evidenced by the increased degree of order (DO) and double helix (DD) ratios. Overall, these findings demonstrate that integrating chickpea flour and controlled homolactic fermentation is an effective strategy for tailoring the viscosity and stability of plant-based probiotic beverages, providing a theoretical basis for the development of clean-label and functional fermented plant-based systems.