Georgina Calderon | Instituto Politecnico Nacional (original) (raw)

Uploads

Papers by Georgina Calderon

Lwt - Food Science and Technology, 2010

The bakery market is developing new technologies based on dough partial baking and the study of t... more The bakery market is developing new technologies based on dough partial baking and the study of the changes that dough undergoes through the whole baking process could help in the selection of baking times. The aim of this work was to study the changes of dough structure and their relationship with dough temperature, mass loss and loaf height during baking by applying image analysis techniques. Results showed that during baking, bubble coalescence was presented, observing a maximum at the first stages of baking (<250 s). This phenomenon was associated with an increment in dough height without a significant change in dough centre temperature. Fractal dimension of texture of crumb, fractal dimension of contour of cells and crumb grain features were useful indicators of coalescence as well as to distinguish the baking time needed for crumb features remain invariable.

Journal of The Science of Food and Agriculture, 2008

BACKGROUND: A study was done to develop procedures for detoxifying Lupinus mutabilis seeds, and d... more BACKGROUND: A study was done to develop procedures for detoxifying Lupinus mutabilis seeds, and decreasing or eliminating yellow colour in derivatives from them. An evaluation was done of the effect of replacement of wheat flour with the detoxified and decolorized L. mutabilis derivatives on the quality properties of three types of bread products (loaf, bun and sweet).RESULTS: Physicochemical and nutritional analyses coincided with previous reports. The Lupinus protein concentrate and isolate had lower phenolic compound and oligosaccharide concentrations than the untreated seeds. Amino acid composition was determined for wheat flour (WF), L. mutabilis defatted and detoxified flour (LF), L. mutabilis protein concentrate (LPC) and L. mutabilis protein isolate (LPI). The resulting values were used to calculate the replacement levels at which lysine content would be increased significantly in WF–lupin blends. Replacement levels were: LF (5%, 10%, 15% and 20%); LPC (2.5%, 5%, 7.5% and 10%); LPI (0.5%, 1%, 2%, 3% and 4%).CONCLUSION: The detoxifying treatments employed decreased non-nutritional and toxic compounds present in original lupin seed. use of citric acid (1%) reduced yellow coloration in LF and LPC. Copyright © 2008 Society of Chemical Industry

Food Science and Biotechnology, 2010

Glucose oxidase (GOX) has been recognized as an alternative to substitute chemical oxidants in br... more Glucose oxidase (GOX) has been recognized as an alternative to substitute chemical oxidants in bread making, however the action exerted on wheat flour proteins by the H2O2 produced is still unclear. Looking for a better understanding of the role of GOX and H2O2 in the bread making process, the effect of varying GOX levels and mixing time on soluble and insoluble wheat flour protein fractions was studied. Results showed that GOX promoted a decrement in free SH groups in both proteins, being the most evident effect on the soluble fraction at the beginning of the mixing process, remaining almost constant afterwards. H2O2 was continuously produced during mixing, showing its largest consumption during the first 6 min without significant SH changes afterwards. Results suggest that H2O2 must be involved in other reactions as it remains in the sample; this also suggests that oxygen is not a limiting factor in this reaction.

Nahrung-food, 2003

Sweet dough requires longer mixing time than salty or white pan bread doughs to reach a developed... more Sweet dough requires longer mixing time than salty or white pan bread doughs to reach a developed stage. Although many studies have dealt with the effect of mixing time on dough, few have referred to yeast sweet doughs. The aim of this study was to evaluate if the changes in dough microstructure during different stages of mixing were the same between sweet pan bread and white pan bread, using as control a flour water system. Scanning electronic microscopy (SEM) and some bread characteristics were used as evaluation parameters. Doughs were prepared in a Brabender Farinograph instrument. Different mixing times were used for each formulation, which correspond to common farinographic parameters such as: arrival time, peak time, departure time, etc. Farinographic consistency was evaluated at those times. Results showed that sweet dough farinogram was quite different from those obtained from the other two samples; it starts with a low consistency value (260 BU( and after 8 min of mixing it began to increase until almost reaching the 500 BU line; then the graphic follows the classical curve. Larger products were obtained from arrival time to departure time for both formulations. SEM showed that as mixing proceeds the dough structure opens, changing its appearance from a compact structure at the beginning to a very open one at the end of the mixing process. SEM also showed that the process of mixing is the same for the two samples and control; however, the time needed to reach each stage was different among samples. Farinogram can be used to get information about mixing behavior of yeast sweet doughs. The study of mixing can be easier using sweet dough formulations because it was possible to get more points between the onset of mixing and full dough development, and the process was very similar no matter the formulation.

Food and Bioprocess Technology

Many approaches to evaluate bread crumb features by applying free or at least not too expensive i... more Many approaches to evaluate bread crumb features by applying free or at least not too expensive image analysis (IA) software have been published; however, the described procedures showed noticeable differences. The aim of this work was to compare different image scanning resolutions and thresholding techniques to quantify sweet bread crumb features (cell density, mean cell area, shape factor) and their relation with fractal dimension. Two sets of experiments were carried out, one to determine the effect of scanning resolution and thersholding method and the other to validate the previous results by evaluating breads with different crumb structures. Nine different scanning resolutions (75, 100, 150, 200, 300, 355, 435, 515, 555 dpi) and two segmentation procedures (Otsu and Manual) were tested. Three different types of commercial sweet breads and a yeasted sweet bread added with different concentrations (six, 12%) of Chia flour (Salvia hispanica) were evaluated. Results showed that the percentage of particles with areas between 0.1 and 4.0 mm2 remained almost constant when using 350 dpi or larger resolution values, while the smallest particles (<0.1 mm2) increased their proportion up to 87% at the highest scanning resolution for both thresholding methods. IA was useful to detect crumb structure differences among commercial breads and breads added with Chia flour as obtained from cell density (154 ± 4.6–246 ± 2.5) and mean cell area (0.81 ± 0.02–0.7 ± 0.03) results. However, the number of selected objects to calculate these parameters produced different results. The addition of 6% of Chia flour did not affect the bread crumb features, while at the largest proportion more and smaller pores were obtained. Fractal texture was useful to evaluate bread crumb structure, as it not depends on the number of particles detected.

Food and Bioprocess Technology

Germinated soybean flour has been proposed for use in bread making as a product to improve bread ... more Germinated soybean flour has been proposed for use in bread making as a product to improve bread quality when small amounts are added to wheat flour. However, it is not clear which soybean components promote this action, and how these components may influence bread quality. The aim of this work was to evaluate the effect of the addition of soybean 7S protein fraction obtained from germinated and nongerminated seeds in dough rheological properties (farinographic and extensographic) and bread quality, including loaf volume, texture (firmness, compression force, resilience), colour (L*, a*, b*), crumb grain structure (cell density, mean cell area, shape factor), and consumer acceptance (sensory analysis). Results showed that this protein fraction just slightly affects bread quality, since no significant changes (P > 0.05) on bread volume and texture were obtained. Only crust and crumb colour were affected in a small amount, and a coarser crumb structure was also observed when adding 7S protein obtained from germinated soybean at its highest concentration. As the proportion of protein increased in the flour, both kinds of 7S fraction (germinated and nongerminated) were related to the increment in water absorption, as well as to the increment in extensographic maximum resistance to extension, specifically when adding 7S protein obtained from nongerminated soybean seeds. These results showed that the 7S soybean protein, as obtained in this work, is not related to the reported loaf bread quality improving effect of this legume when it is added in small quantities.

Lwt - Food Science and Technology, 2010

The bakery market is developing new technologies based on dough partial baking and the study of t... more The bakery market is developing new technologies based on dough partial baking and the study of the changes that dough undergoes through the whole baking process could help in the selection of baking times. The aim of this work was to study the changes of dough structure and their relationship with dough temperature, mass loss and loaf height during baking by applying image analysis techniques. Results showed that during baking, bubble coalescence was presented, observing a maximum at the first stages of baking (<250 s). This phenomenon was associated with an increment in dough height without a significant change in dough centre temperature. Fractal dimension of texture of crumb, fractal dimension of contour of cells and crumb grain features were useful indicators of coalescence as well as to distinguish the baking time needed for crumb features remain invariable.

Journal of The Science of Food and Agriculture, 2008

BACKGROUND: A study was done to develop procedures for detoxifying Lupinus mutabilis seeds, and d... more BACKGROUND: A study was done to develop procedures for detoxifying Lupinus mutabilis seeds, and decreasing or eliminating yellow colour in derivatives from them. An evaluation was done of the effect of replacement of wheat flour with the detoxified and decolorized L. mutabilis derivatives on the quality properties of three types of bread products (loaf, bun and sweet).RESULTS: Physicochemical and nutritional analyses coincided with previous reports. The Lupinus protein concentrate and isolate had lower phenolic compound and oligosaccharide concentrations than the untreated seeds. Amino acid composition was determined for wheat flour (WF), L. mutabilis defatted and detoxified flour (LF), L. mutabilis protein concentrate (LPC) and L. mutabilis protein isolate (LPI). The resulting values were used to calculate the replacement levels at which lysine content would be increased significantly in WF–lupin blends. Replacement levels were: LF (5%, 10%, 15% and 20%); LPC (2.5%, 5%, 7.5% and 10%); LPI (0.5%, 1%, 2%, 3% and 4%).CONCLUSION: The detoxifying treatments employed decreased non-nutritional and toxic compounds present in original lupin seed. use of citric acid (1%) reduced yellow coloration in LF and LPC. Copyright © 2008 Society of Chemical Industry

Food Science and Biotechnology, 2010

Glucose oxidase (GOX) has been recognized as an alternative to substitute chemical oxidants in br... more Glucose oxidase (GOX) has been recognized as an alternative to substitute chemical oxidants in bread making, however the action exerted on wheat flour proteins by the H2O2 produced is still unclear. Looking for a better understanding of the role of GOX and H2O2 in the bread making process, the effect of varying GOX levels and mixing time on soluble and insoluble wheat flour protein fractions was studied. Results showed that GOX promoted a decrement in free SH groups in both proteins, being the most evident effect on the soluble fraction at the beginning of the mixing process, remaining almost constant afterwards. H2O2 was continuously produced during mixing, showing its largest consumption during the first 6 min without significant SH changes afterwards. Results suggest that H2O2 must be involved in other reactions as it remains in the sample; this also suggests that oxygen is not a limiting factor in this reaction.

Nahrung-food, 2003

Sweet dough requires longer mixing time than salty or white pan bread doughs to reach a developed... more Sweet dough requires longer mixing time than salty or white pan bread doughs to reach a developed stage. Although many studies have dealt with the effect of mixing time on dough, few have referred to yeast sweet doughs. The aim of this study was to evaluate if the changes in dough microstructure during different stages of mixing were the same between sweet pan bread and white pan bread, using as control a flour water system. Scanning electronic microscopy (SEM) and some bread characteristics were used as evaluation parameters. Doughs were prepared in a Brabender Farinograph instrument. Different mixing times were used for each formulation, which correspond to common farinographic parameters such as: arrival time, peak time, departure time, etc. Farinographic consistency was evaluated at those times. Results showed that sweet dough farinogram was quite different from those obtained from the other two samples; it starts with a low consistency value (260 BU( and after 8 min of mixing it began to increase until almost reaching the 500 BU line; then the graphic follows the classical curve. Larger products were obtained from arrival time to departure time for both formulations. SEM showed that as mixing proceeds the dough structure opens, changing its appearance from a compact structure at the beginning to a very open one at the end of the mixing process. SEM also showed that the process of mixing is the same for the two samples and control; however, the time needed to reach each stage was different among samples. Farinogram can be used to get information about mixing behavior of yeast sweet doughs. The study of mixing can be easier using sweet dough formulations because it was possible to get more points between the onset of mixing and full dough development, and the process was very similar no matter the formulation.

Food and Bioprocess Technology

Many approaches to evaluate bread crumb features by applying free or at least not too expensive i... more Many approaches to evaluate bread crumb features by applying free or at least not too expensive image analysis (IA) software have been published; however, the described procedures showed noticeable differences. The aim of this work was to compare different image scanning resolutions and thresholding techniques to quantify sweet bread crumb features (cell density, mean cell area, shape factor) and their relation with fractal dimension. Two sets of experiments were carried out, one to determine the effect of scanning resolution and thersholding method and the other to validate the previous results by evaluating breads with different crumb structures. Nine different scanning resolutions (75, 100, 150, 200, 300, 355, 435, 515, 555 dpi) and two segmentation procedures (Otsu and Manual) were tested. Three different types of commercial sweet breads and a yeasted sweet bread added with different concentrations (six, 12%) of Chia flour (Salvia hispanica) were evaluated. Results showed that the percentage of particles with areas between 0.1 and 4.0 mm2 remained almost constant when using 350 dpi or larger resolution values, while the smallest particles (<0.1 mm2) increased their proportion up to 87% at the highest scanning resolution for both thresholding methods. IA was useful to detect crumb structure differences among commercial breads and breads added with Chia flour as obtained from cell density (154 ± 4.6–246 ± 2.5) and mean cell area (0.81 ± 0.02–0.7 ± 0.03) results. However, the number of selected objects to calculate these parameters produced different results. The addition of 6% of Chia flour did not affect the bread crumb features, while at the largest proportion more and smaller pores were obtained. Fractal texture was useful to evaluate bread crumb structure, as it not depends on the number of particles detected.

Food and Bioprocess Technology

Germinated soybean flour has been proposed for use in bread making as a product to improve bread ... more Germinated soybean flour has been proposed for use in bread making as a product to improve bread quality when small amounts are added to wheat flour. However, it is not clear which soybean components promote this action, and how these components may influence bread quality. The aim of this work was to evaluate the effect of the addition of soybean 7S protein fraction obtained from germinated and nongerminated seeds in dough rheological properties (farinographic and extensographic) and bread quality, including loaf volume, texture (firmness, compression force, resilience), colour (L*, a*, b*), crumb grain structure (cell density, mean cell area, shape factor), and consumer acceptance (sensory analysis). Results showed that this protein fraction just slightly affects bread quality, since no significant changes (P > 0.05) on bread volume and texture were obtained. Only crust and crumb colour were affected in a small amount, and a coarser crumb structure was also observed when adding 7S protein obtained from germinated soybean at its highest concentration. As the proportion of protein increased in the flour, both kinds of 7S fraction (germinated and nongerminated) were related to the increment in water absorption, as well as to the increment in extensographic maximum resistance to extension, specifically when adding 7S protein obtained from nongerminated soybean seeds. These results showed that the 7S soybean protein, as obtained in this work, is not related to the reported loaf bread quality improving effect of this legume when it is added in small quantities.