DSpace Angular :: Browsing by Author "Miguel Aguilera, Jose"

Browsing by Author "Miguel Aguilera, Jose"

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Automated fish bone detection using X-ray imaging
(ELSEVIER SCI LTD, 2011) Mery, Domingo; Lillo, Ivan; Loebel, Hans; Riffo, Vladimir; Soto, Alvaro; Cipriano, Aldo; Miguel Aguilera, Jose
In countries where fish is often consumed, fish bones are some of the most frequently ingested foreign bodies encountered in foods. In the production of fish fillets, fish bone detection is performed by human inspection using their sense of touch and vision which can lead to misclassification. Effective detection of fish bones in the quality control process would help avoid this problem. For this reason, an X-ray machine vision approach to automatically detect fish bones in fish fillets was developed. This paper describes our approach and the corresponding experiments with salmon and trout fillets. In the experiments, salmon X-ray images using 10 x 10 pixels detection windows and 24 intensity features (selected from 279 features) were analyzed. The methodology was validated using representative fish bones and trouts provided by a salmon industry and yielded a detection performance of 99%. We believe that the proposed approach opens new possibilities in the field of automated visual inspection of salmon, trout and other similar fish. (C) 2011 Elsevier Ltd. All rights reserved.
Description of the kinetic enzymatic browning in banana (Musa cavendish) slices using non-uniform color information from digital images
(ELSEVIER, 2009) Quevedo, Roberto; Diaz, Oscar; Ronceros, Betty; Pedreschi, Franco; Miguel Aguilera, Jose
A novel methodology "fractal browning indicator" (FBI) is presented, that describes the enzymatic browning kinetic based on the use of irregular color patterns from banana slice images. It uses the fractal Fourier texture image value in a selected area, to calculate a fractal dimension (FD), which represents the complexity of color distribution. During the procedure, colors from digital images were first transformed to L*a*b* space color using a transformation function (quadratic model), in order to derivate three color channels, lightness (L*), redness (a*), and yellowness (b*). In the results, lightness and yellowness parameters decreased during the browning kinetic, when their respective FD values increased, indicating major color distribution complexity in a selected area analyzed during the kinetic. The redness color (a*) did not show any statistical variation. The empirical power law model was suitable to correlate enzymatic browning kinetic data both for FBI and for the traditional method (when an L* mean was used). However, enzymatic browning rates using the FBI method, were between 8.5 and 35 times higher than rates calculated with the traditional method. (C) 2009 Elsevier Ltd. All rights reserved.
Effect of a Whey Protein Network Formed by Cold Gelation on Starch Digestibility
(2019) Lavoisier, Anais; Miguel Aguilera, Jose
Composite gels of whey protein isolate (WPI) and potato starch (PS) were formed by calcium chloride induced cold gelation to obtain microstructures where native starch granules were encased in the WPI network. Gels were then subjected to heat treatment and PS gelatinized inside the protein network. In vitro starch digestibility was investigated using the INFOGEST protocol to explore if the protein gel was able to protect gelatinized starch granules from enzymatic attack during digestion. This study was focused on the impact of gel particle size and protein concentration on glucose release from the matrix. Mechanical and rheological properties of the composite gels were also evaluated after heat treatment. Glucose release from the matrix was reduced until the intestinal step of the simulated digestion when gels were ground to a particle size of 1mm. When gels were cut to a particle size of 5mm glucose release was decreased until the end of the test. In this case, at the end of the digestion glucose release was reduced by 15.5 and 20.5% for composite gels with 8 and 10% WPI respectively, whereas no significant reduction was observed for the gel with 6% WPI. Therefore, the effect of the WPI network on starch digestibility depended on particle size and on protein concentration. Mechanical and rheological properties of the gels were related to starch digestibility: PS hydrolysis rate decreased with increasing hardness and elasticity of the gels. This work contributes to a better understanding of starch digestion in soft food matrices.
Effect of guar gum content on some physical and nutritional properties of extruded products
(ELSEVIER SCI LTD, 2011) Parada, Javier; Miguel Aguilera, Jose; Brennan, Charles
The effect of guar gum (0-10%) added to flour (maize, potato, rice, and wheat) prior to extrusion on the microstructure, physical properties (texture, expansion, density, pasting) and nutritional properties (starch digestibility) was investigated. The inclusion of guar gum did not decrease starch digestibility; rather, at 10% guar gum rapidly digestible starch increased by 24%, 15%, 25% and 43%, in maize, potato, rice and wheat flour-based products, respectively. In general, increases in starch digestibility appear to be related to the weaker microstructure (i.e., lower textural hardness), larger matrix surface area, and lower viscosity (pasting properties) of extrudates containing guar gum. These results suggest that microstructural changes affect the starch digestibility of extrudates; nevertheless, probably other factors such as particle size during digestion may also play an important role. (C) 2010 Elsevier Ltd. All rights reserved.
Fabrication, characterization and lipase digestibility of food-grade nanoemulsions
(ELSEVIER SCI LTD, 2012) Troncoso, Elizabeth; Miguel Aguilera, Jose; McClements, David Julian
The behavior of nanoemulsion-based delivery systems within the gastrointestinal tract determines their functional performance. In this study, the influence of particle radius (30-85 nm) on the in vitro digestion of nanoemulsions containing non-ionic surfactant stabilized lipid (corn oil) droplets was examined using simulated small intestine conditions. Nanoemulsions were prepared by a combination of high-pressure homogenization and solvent (hexane) displacement. Lipid droplets with different sizes were prepared by varying the oil-to-solvent ratio in the disperse phase prior to homogenization. The fraction of free fatty acids (FFA) released from emulsified triacylglycerols (TG) during digestion was measured by an in vitro model (pH-Stat titration). Nanoemulsions exhibited a lag-period before any FFA were released, which was explained by inhibition of lipase adsorption to the oil-water interface by free surfactant. After the lag-period, the digestion rate increased with decreasing oil droplet diameter (increasing specific surface area). The total amount of FFA released from the emulsions increased from 61% to 71% as the mean droplet radius decreased from 86 nm to 30 nm. The incomplete digestion of the emulsified lipids could be explained by inhibition of lipase activity by the release of fatty acids and/or by interactions between lipase and surfactants molecules. (C) 2011 Elsevier Ltd. All rights reserved.
Influence of particle size on the in vitro digestibility of protein-coated lipid nanoparticles
(ACADEMIC PRESS INC ELSEVIER SCIENCE, 2012) Troncoso, Elizabeth; Miguel Aguilera, Jose; McClements, David Julian
The influence of particle size on the in vitro digestion of beta-lactoglobulin (BLG)-coated lipid nanoparticles was examined using simulated small intestine conditions. Nanoemulsions were prepared by high-pressure homogenization and organic solvent (hexane) evaporation. The effect of the initial organic phase composition on the size, microstructure, electrical properties, and digestion of the lipid nanoparticles was evaluated. The radius of the nanoparticles decreased (from 85 to 48 nm) as the solvent concentration in the initial organic phase increased (from 0% to 95%). The lipid digestion rate initially decreased with decreasing particle radius (for r = 85-59 nm), but then it increased (for r = 59-48 nm). This dependence is contrary to the usual assumption that lipid digestion increases with increasing lipid surface area. Our results suggest that the structure of the protein layer coating the lipid nanoparticles has an important effect on lipid digestion. (C) 2012 Elsevier Inc. All rights reserved.
Quality classification of corn tortillas using computer vision
(ELSEVIER SCI LTD, 2010) Mery, Domingo; Chanona Perez, Jorge J.; Soto, Alvaro; Miguel Aguilera, Jose; Cipriano, Aldo; Velez Rivera, Nayeli; Arzate Vazquez, Israel; Gutierrez Lopez, Gustavo F.
Computer vision is playing an increasingly important role in automated visual food inspection. However, quality control in tortilla production is still performed by human operators which may lead to misclassification due to their subjectivity and fatigue. In order to reduce the need for human operators and therefore misclassification, we developed a computer vision framework to automatically classify the quality of corn tortillas according to five hedonic sub-classes given by a sensorial panel. The proposed framework analyzed 750 corn tortillas obtained from 15 different Mexican commercial stores which were either small, medium or large in size. More than 2300 geometric and color features were extracted from 1500 images capturing both sides of the 750 tortillas. After implementing a feature selection algorithm, in which the most relevant features were selected for the classification of the five sub-classes, only 64 features were required to design a classifier based on support vector machines. Cross-validation yielded a performance of 95% in the classification of the five hedonic sub-classes. Additionally, using only 10 of the selected features and a simple statistical classifier, it was possible to determine the origin of the tortillas with a performance of 96%. We believe that the proposed framework opens up new possibilities in the field of automated visual inspection of tortillas. (c) 2010 Elsevier Ltd. All rights reserved.
Quantification of enzymatic browning in apple slices applying the fractal texture Fourier image
(ELSEVIER SCI LTD, 2009) Quevedo, Roberto; Jaramillo, Marcela; Diaz, Oscar; Pedreschi, Franco; Miguel Aguilera, Jose
A new approach (FBI) describing the enzymatic browning kinetics for three apple cultivars, is presented. It is based on quantification of the irregular color patterns that emerge from the apple surface during enzymatic browning, rather than using the color average in the same area analyzed. In the experiments, three apple cultivars slices were placed under a computer vision system and color digital images were captured. The images were transformed to Lab space color using a quadratic transformation function and the Fourier fractal texture image was used to calculate a fractal dimension value (FD), in order to represent the complexity of lightness intensity distribution (L) over the surface. FD (proposed method) and the mean L value (traditional method) were used indistinctly (as a fractional conversion) to model the enzymatic kinetic using the power-law model. The results showed that the fractal theory can be used to describe the browning kinetic and to distinguish apple cultivars, based on their browning sensitivity under the same experimental conditions. Enzymatic browning rates derived using the fractal kinetic method, were between 14.3 and 23.2 times (in absolute value) higher than the rates calculated with the traditional method. The fractional first-order model was established only for kinetics calculated using the traditional method. (c) 2009 Elsevier Ltd. All rights reserved.
Rational food design and food microstructure
(2022) Miguel Aguilera, Jose
Background: Consumers' demands are changing how foods are produced, processed, and delivered. In this respect, the term rational food design (RFD) appears in an increasing number of scientific articles without much explanation of its precise meaning. Attempting a definition of the concept supported by several examples would facilitate and encourage its applications in food research and product development.Scope and approach: The aims of this review are to (i) discuss advances in the rational design of foods resulting in improved product properties; (ii) address the role of food microstructure and the food matrix in achieving specific functional targets in several food products; and (iii) comment on the most active areas of food microstructure research, use of imaging techniques and the interfaces with other scientific disciplines.Key findings and conclusions: The article proposes that RFD is expressing the desirable sensorial, emotional, nutrition, and health properties of foods as functional multiscale microstructures and matrices following an integrated knowledge-based process that utilizes a versatile multidisciplinary toolbox. RFD is used advantageously in the development of delivery systems for nutraceuticals, redesigned/reformulated traditional products, gastronomic creations, personalized foods, applications for novel food sources, innovative plant-based foods and meat analogs, and matrices to feed a healthy microbiota. RFD implies working at interfaces with various disciplines outside the direct realm of food science and technology, thus nurturing from their knowledge and tools.
Sensory descriptors for three edible Chilean seaweeds and their relations to umami components and instrumental texture
(2022) Figueroa, Valentina; Bunger, Andrea; Ortiz, Jaime; Miguel Aguilera, Jose
Although seaweeds exhibit many benefits as a food source, few studies have characterized their sensory attributes. An expert nine-member panel developed a vocabulary with 25 descriptors to describe the appearance, aroma, flavor, texture, and aftertaste of raw and cooked seaweeds consumed in Chile: Durvillaea antarctica, Pyropia spp., and Ulva lactuca. Subsequently, the vocabulary was used in a ranking descriptive analysis (RDA) to evaluate the sensory properties and relate them with physicochemical and physical data. Sensory attributes of the three seaweeds were very different from each other but similar between treatments (raw and cooked). Pyropia spp., both cooked and hydrated, had the highest glutamate content (310 and 324 mg (100 g)(-1) d.w., respectively), and was perceived by the sensory panel as having the most umami taste. Cooked D. antarctica was perceived as sweeter, had more caramel notes than the hydrated seaweed and was sensed as cartilaginous and hard in accordance with its mechanical properties. Generalized Procrustes analysis revealed that D. antarctica exhibited most of the desirable descriptors, such as caramel, umami and marine aromas while U. lactuca was described as bitter and moldy. This primary vocabulary can assist food scientists and chefs in the development of seaweed products and dishes for the consumer market.
Starch gelatinization inside a whey protein gel formed by cold gelation
(2019) Lavoisier, Anais; Miguel Aguilera, Jose
Native potato starch (PS) granules were trapped within a whey protein network formed by cold gelation. Heat treatment of these composite gels induced PS gelatinization inside the protein network, which was studied with a DSC/hot-stage system and confocal laser scanning microscopy. Gelatinization inside the protein network was also indirectly followed by rheological measurements and mechanical properties of the composite gels measured before and after heat treatment. The presence of the protein network shortened the gelatinization by 3 degrees C, reduced the gelatinization enthalpy by 42% and significantly restricted granules swelling. The rheological and mechanical properties of the gels were influenced by PS swelling, depending on starch concentration. After reheating to 90 degrees C, the addition of 1% PS resulted in a weakening of the gel. However, the addition of 9% PS led to a reinforcement of the gel, probably due to the formation of an interpenetrating network between whey proteins and the gelatinized PS.

Browsing by Author "Miguel Aguilera, Jose"

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