Browsing by Author "Osorio, Fernando"

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    A non-destructive digital imaging method to predict immobilized yeast-biomass
    (ELSEVIER, 2009) Acevedo, Cristian A.; Skurtys, Olivier; Young, Manuel E.; Enrione, Javier; Pedreschi, Franco; Osorio, Fernando
    In food fermentation, many types of immobilization systems are used, such as hydrogel entrapment, where alginate is the main biopolymer. one of the important problems in industrial processes is the quantifications of biomass, since the traditional system of direct cell counting cannot be used. In this study, a simple digital imaging method to determine the biomass of yeasts immobilized into alginate capsules was developed. Important evidence of the yeasts growing inside the alginate was the change in the surface color of the capsule. Digital images were taken with different biomass concentration, and the RGB-analysis showed significant differences in the blue field. The histogram of the blue channel was used to develop a PLS multivariate calibration to predict biomass concentration. The method was validated in primary beer fermentation with good efficiency. (C) 2009 Elsevier Ltd. All rights reserved.
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    Effect of Mannoprotein-Producing Yeast on Viscosity and Mouthfeel of Red Wine
    (Multidisciplinary Digital Publishing Institute (MDPI), 2025) Núñez Ferrada, Emerson Andrés; Vidal Zuñiga, Josefina Victoria; Chávez Muñoz, Matías Jesús; Bordeu Schwarze, Edmundo; Osorio, Fernando; Vargas, Sebastian; Hormazabal, Elba; Brossard Aravena, Natalia Daniela
    Mannoproteins enhance wine stability and sensory properties, but their specific role in modulating viscosity and mouthfeel across wine quality levels remains underexplored. This study explores the nuanced impact of various mannoprotein-producing yeast strains on specific mouthfeel sensations, particularly emphasizing viscosity, across Standard and Premium quality tiers of Cabernet Sauvignon commercial wines. The aim was to understand the intricate relationship between yeast-derived mannoproteins and the broader sensory landscape of red wines. The methodology encompasses a comprehensive mannose extraction method, rheological measurements, and sensory Rate-All-That-Apply evaluations, all of which are integrated into a Principal Component Analysis. The results showed slight color variations due to the wine spending one month on lees. A positive correlation was found between mannose content and viscosity in only Standard-quality wines. The correlation with sensory data indicated a strong relationship between volume, viscosity, and mannose content in Premium-quality wines, which was less pronounced in Standard-quality wines. Furthermore, parameters related to mouthfeel quality, such as roundness and smoothness, were also associated with these findings. Prospects involve further exploration of correlations between mouthfeel sensations, sensory descriptors, and the structural characteristics of mannoproteins, aiming for a more comprehensive understanding of the intricate interplay in wine composition.
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    Physical properties of emulsion-based hydroxypropyl methylcellulose/whey protein isolate (HPMC/WPI) edible films
    (2015) Rubilar Parra, Javiera Fernanda; Zúñiga, Rommy N.; Osorio, Fernando; Pedreschi Plasencia, Franco
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    Prediction of the Glass Transition Temperature on Extruded Waxy Maize and Rice Starches in Presence of Glycerol
    (Springer Nature, 2010) Enrione, Javier; Osorio, Fernando; Pedreschi Plasencia, Franco; Hill, Sandra
    Polymer science approach has shown to be useful to understand the structural complexity of food systems. This work looks at the effect of glycerol (5%, 10%, and 20% (dry weight basis)) on the glass transition temperature (Tg) of a starchy matrix determined by DSC and its prediction using Ten-Brinke-Karasz equation. Waxy maize starch (WMS) and rice starch (RS) systems were prepared by thermomechanical extrusion. A decrease in Tg, from similar to 170 to similar to 25 A degrees C, was detected for both starches (0% glycerol) when the moisture increased from 5% to 25% (wet weight basis (wb)). When glycerol was added, a further decrease in Tg was obtained. Tg was reduced from 120 to 60 A degrees C and 45 A degrees C for 10% and 20% glycerol, respectively, at a moisture content of 10% (wb). A direct comparison between starches with similar composition showed equal Tg (P > 0.05). The modeling for the control samples (0% glycerol) gave a Delta Cp similar to aEuro parts per thousand 0.4 Jg(-1) K-1 for WMS and RS and similar to 1.9 Jg(-1) K-1 for water. These values can be explained by the well-known Tg dependence on degree of polymerization and molecular weight. When the glycerol concentration was increased, an increase was observed, Delta Cp similar to aEuro parts per thousand 0.6 Jg(-1) K--1,K- for both starches and similar to 2.8 Jg(-1) K-1 for water. This behavior would indicate an overestimation in the plasticizing effect of glycerol due to the possible occurrence of polyol-rich fractions in the extruded samples.
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    Using RGB Image Processing for Designing an Alginate Edible Film
    (2012) Acevedo, Cristian A.; Lopez, Dario A.; Tapia, Maria J.; Enrione, Javier; Skurtys, Olivier; Pedreschi, Franco; Brown, Donald I.; Creixell, Werner; Osorio, Fernando
    The use of edible films to coat food products is a technique that allows for an extended shelf-life. One of the most widely used polymers is calcium alginate. However, this polymer can modify the original food color and the perception by consumers. The objective was to design an alginate film based principally on color changes using a RGB color model. Edible films were prepared with sodium alginate and glycerol as plasticizer, cross-linking the polymer with calcium. Dry and hydrated states of the edible films were studied. Film thickness was directly proportional to surface concentration and increased with hydration. There is a zone in which the color does not change with alginate surface concentration and another where the color is directly proportional to it. This latter scenario is not a consequence of structural changes or the degree of hydration. Results showed a range where the color was not modified by the alginate concentration; hence, an optimal surface concentration was determined as a design parameter. Edible films made using the optimal surface concentration would not mask microbial contamination and have good physical properties (water vapor transmission and swelling) compared with other surface concentrations. In addition, it was possible to model alginate surface concentration as a function of surface color using mathematical tools (clustering, linear regression, and support vector machine), allowing one to study the optimal use of the edible films.