Browsing by Author "Moreno Constenla, María Carolina"

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    Rheological and tribological properties of seaweed powders as thickeners for liquid foods
    (2024) Covacevich Flores, Leyla Francisca; Aguilera Radic, José Miguel; Moreno Constenla, María Carolina; Brossard Aravena, Natalia Daniela; Osorio Lira, Fernando Alberto
    Thickened liquid foods are particularly interesting in culinary applications and the management of swallowing disorders. Polysaccharide molecules and suspended soft particles play a major role in increasing viscosity and mouthfeel. In this work, tribo-rheological effects of finely ground particles (less than 75 microns) of Durvillaea antarctica seaweed (SP) as a minimally processed and natural alternative to commercial thickeners were studied. Shear viscosity (η), viscoelastic moduli (G’, G’’), and the coefficient of friction (CoF) were determined for SP dispersions, using as controls two commercial thickeners: modified maize starch-based (TE) and xanthan gum-based (TU). SP and SP dispersions were characterized microstructurally and evaluated at concentrations of 1.2%, 2.4%, and 4.8% w/v, with and without artificial saliva (AS). SP dispersions exhibited a pseudoplastic behavior in the range of shear rates 0.1-100 s-1 and viscoelasticity (G’>G”) in the 0.1-80 rad/s frequency range. The incorporation of AS had a dilution effect in SP and TU dispersions, but additionally, in the case of TE, a hydrolyzing effect decreased the values of the responses. In the tribology experiments, all samples followed a Stribeck curve. SP dispersions were more lubricating than AS and controls in the physiological range of velocities during oral processing and swallowing (e.g.,>100 mm/s). The thickening, viscoelastic, and lubrication behavior of SP dispersions were attributed to the soluble solids released from the SP (37%-51% d.w.) and interactions with ghosts of SP particles in the continuous aqueous phase. Fine seaweed particles may be a sustainable and low-cost alternative to commercial thickeners in some food applications
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    Understanding the structure and functionality of third-generation rice flour snacks enriched with grape pomace flour
    (Elsevier Ltd., 2025) Arazo Rusindo, Migdalia Caridad; Oyarzún Durbahn, Mauricio Ignacio; Moreno Constenla, María Carolina; Bouchon Aguirre, Pedro Alejandro
    Extrusion can yield expanded products or non-expanded pellets, which are later expanded in a separate thermal device to form third-generation (3 G) snacks. In both processes, ingredient effects on structure formation and functional ingredient retention are challenging. This study analyzed the effect of adding 0-15 % grape pomace flour (GPF), a by-product of the wine industry, to rice flour pellets extruded at maximum temperatures of 110 and 150 degrees C using twin-screw extrusion and then microwave-expanded (30 s at 480 W), to understand the relationship between microstructural parameters of 3 G snacks and their physical and textural properties, total polyphenol content (TPC), and antioxidant capacity. Results showed that adding GPF increased bulk density (from 0.12 to 0.39 g/cm3), hardness (from 29.5 to 37.59 N), and crispness, while decreasing the expansion index (from 1.83 to 1.65). Micro-CT analysis revealed that extrusion temperature did not affect microstructural parameters, but high GPF levels (15 %) reduced porosity and mean pore size, and increased wall thickness. Extrusion reduced the initial TPC in pellets by up to 52 %, but microwave expansion increased it by up to 37 %, likely due to polyphenol release from the dense glassy matrix of the pellets. These findings highlight the potential for creating nutritionally enhanced 3 G snacks using agricultural by-products like GPF and underscore the importance of a microstructural approach in the analysis.