María Susana Rodríguez - Academia.edu (original) (raw)

Papers by María Susana Rodríguez

Research paper thumbnail of Chitooligosaccharides as novel ingredients of fermented foods

Food & Function, 2015

Chitooligosaccharides can be added to yoghurt at low concentrations without affecting its nutriti... more Chitooligosaccharides can be added to yoghurt at low concentrations without affecting its nutritional composition and sensory acceptance.

Research paper thumbnail of Valoración de la eficacia de quitooligosacárido proveniente de recursos del Mar Argentino para el control de Fusarium eumartii

Fil: Mansilla, Andrea Yamila. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro ... more Fil: Mansilla, Andrea Yamila. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Mar del Plata. Instituto de Investigaciones Biologicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Biologicas; Argentina

Research paper thumbnail of The Water-Soluble Chitosan Derivative, N-Methylene Phosphonic Chitosan, Is an Effective Fungicide against the Phytopathogen Fusarium eumartii

The Plant Pathology Journal, 2021

Chitosan has been considered an environmental-friendly polymer. However, its use in agriculture h... more Chitosan has been considered an environmental-friendly polymer. However, its use in agriculture has not been extended yet due to its relatively low solubility in water. N-Methylene phosphonic chitosan (NMPC) is a water-soluble derivative prepared by adding a phosphonic group to chitosan. This study demonstrates that NMPC has a fungicidal effect on the phytopathogenic fungus Fusarium solani f. sp. eumartii (F. eumartii) judged by the inhibition of F. eumartti mycelial growth and spore germination. NMPC affected fungal membrane permeability, reactive oxygen species production, and cell death. Also, this chitosan-derivative exerted antifungal effects against two other phytopathogens, Botrytis cinerea, and Phytophthora infestans. NMPC did not affect tomato cell viability at the same doses applied to these phytopathogens to exert fungicide action. In addition to water solubility, the selective biological cytotoxicity of NMPC adds value in its application as an antimicrobial agent in agri...

Research paper thumbnail of Biodegradable films based on thermoplastic starch and chitosan with antimicrobial activity employed as active packaging

One of the research lines related to active packaging takes into account the incorporation of ant... more One of the research lines related to active packaging takes into account the incorporation of antimicrobial agents such as chitosan, a polysaccharide derived from the crustaceans' exoskeleton. However, because of chitosan high molar mass, its diffusion from the package to the food surface is restricted, so the use of oligomers is an interesting but less investigated alternative. The purpose of this work was to obtain active films based on thermoplastic corn starch (TPS) by adding oligochitosans (OC, molar mass = 290 g mol-1 and degree of polimerization = 2). Films were thermo-compressed in a hydraulic press. Diffusion assays of OC from TPS matrix to liquid medium with different acidity degree (pH = 3, 5, and 7) were performed. Liquid medium conditions were selected according to the acidity of a wide variety of foods. From these assays, oligomers diffusion capacity and the dependence with pH were demonstrated. The efficiency of OC incorporation in packaging material was compared ...

Research paper thumbnail of Película biodegradable de almidón de maíz termoplástico y quitosano con actividad antimicrobiana empleada como envase activo

Matéria (Rio de Janeiro), 2018

RESUMEN Una de las líneas para el desarrollo de envases activos contempla la incorporación de age... more RESUMEN Una de las líneas para el desarrollo de envases activos contempla la incorporación de agentes antimicrobianos como el quitosano, polisacárido derivado del exoesqueleto de crustáceos. No obstante, su elevada masa molar restringe su difusión desde el envase hacia el alimento por lo que el empleo de oligómeros de características diferenciales es una alternativa interesante, aún poco investigada. El objetivo de este trabajo fue obtener películas activas a base de almidón de maíz termoplástico (TPS) mediante la incorporación de oligoquitosanos (OQ, masa molar = 290 g mol-1 y grado de polimerización = 2). Estos materiales fueron obtenidos mediante termo-compresión en una prensa hidráulica. Se realizaron ensayos de difusión de los OQ desde la matriz de TPS hacia un medio líquido con diferentes grados de acidez (pH = 3, 5 y 7). Las condiciones del medio líquido fueron seleccionadas según la acidez de una amplia variedad de alimentos. A partir de estos ensayos, se demostró la capacid...

Research paper thumbnail of Chitosan Interaction with Iron from Yoghurt Using an In Vitro Digestive Model: Comparative Study with Plant Dietary Fibers

International Journal of Molecular Sciences, 2011

The objective of this work was to investigate the interaction of chitosan with iron from yoghurt ... more The objective of this work was to investigate the interaction of chitosan with iron from yoghurt by an in vitro gastrointestinal tract model. Taking into account that chitosan is a polysaccharide included in fiber definition by Codex Alimentarius; chitosan behavior was studied and compared with different plant fiber (wheat, bamboo, apple, psyllium and inulin) behaviors, in the same in vitro conditions. Ferrous sulfate was added to yoghurts with each type of fiber. The gastric environment was simulated with HCl (pH 1.0-2.0). The duodenal environment was simulated with NaHCO 3 (pH 6.8-7.2) and a dialysis tubing cellulose membrane. Results showed that chitosan had the highest iron retention percentages (53.2% at 30 min; 56.8% at 60 min) interacting in a more pronounced manner with iron than the plant fibers used in this work.

Research paper thumbnail of Nitric oxide-mediated cell death is triggered by chitosan in F. eumartii spores

Pest Management Science, 2014

The genus Fusarium comprises a heterogeneous group of fungi important for agriculture. Fusarium s... more The genus Fusarium comprises a heterogeneous group of fungi important for agriculture. Fusarium solani f. sp. eumartii (F. eumartii), historically considered to be a fungal pathogen of potato, has also been associated with tomato disease. Currently, chitosan and its derivatives have been receiving more attention as environmentally friendly antimicrobial compounds in sustainable practices. The aim of the present work was to characterize downstream events associated with the mode of action of chitosan, including nitrosative reactive species, in order to identify new biomarkers of its cytotoxic action. Data indicated that chitosan-mediated nitric oxide (NO) production might lead to conidial death, concomitant with the strong reduction in fungal pathogenicity in tomato plants. Following chitosan applications, a notably dose-dependent reduction in conidial viability was demonstrated in F. eumartii. Thereafter, the infectivity of chitosan-treated spores was tested by a bioassay using tomato seedlings. All these data highlight NO valuable properties as a quantitative and qualitative biomarker of cytotoxic action of chitosan in conidial cells. In addition, these findings place the chitosan assayed here as a fungicide with a high potential of application in sustainable horticultural practices. © 2014 Society of Chemical Industry.

Research paper thumbnail of Present and Future Role of Chitin and Chitosan in Food

Macromolecular Bioscience, 2003

Research paper thumbnail of Synthesis and characterization of N-propyl-N-methylene phosphonic chitosan derivative

Carbohydrate Polymers, 2010

A simple methodology for the preparation of a new chitosan derivative called N-propyl-N-methylene... more A simple methodology for the preparation of a new chitosan derivative called N-propyl-N-methylene phosphonic chitosan (PNMPC) is proposed. Introduction of a propyl chain onto a modified chitosan (N-methylene phosphonic chitosan) offers the presence of hydrophobic and hydrophilic branches for controlling solubility properties of the new derivative. Its chemical identity was determined by FT-IR, 1H, 13C and 31P NMR spectroscopy. The

Research paper thumbnail of Chitosan influence on glucose and calcium availability from yogurt: In vitro comparative study with plants fibre

Carbohydrate Polymers, 2008

... Acknowledgements. Financial support from Universidad Nacional del Sur is gratefully acknowled... more ... Acknowledgements. Financial support from Universidad Nacional del Sur is gratefully acknowledged. Marina Dello Staffolo, Miriam Martino and Alicia Bevilacqua express their gratitude to Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) Argentina. ...

Research paper thumbnail of Interaction between Chitosan and Oil under Stomach and Duodenal Digestive Chemical Conditions

Bioscience, Biotechnology, and Biochemistry, 2005

Chitosan, the N acetylated derivative of chitin, has an effect on the absorption of dietary lipid... more Chitosan, the N acetylated derivative of chitin, has an effect on the absorption of dietary lipids, but there is not enough scientific knowledge about the mechanism. To study the interaction between chitosan and oil, the action of this biopolymer has been evaluated through an experimental model of the stomach and duodenum tract, although the enzimatic activity had not been evaluated. We microscopically confirmed that chitosan in a hychloridic acid medium (pH 1.0-2.0) emulsified lipids and the emulsion was a water in oil in water type (w/o/ w). When the pH value and speed of agitation were increased to mirror the duodenum medium conditions under which lipids are absorbed, the emulsion capacity was better with an increased number of droplets and the emulsion continued as the w/o/w type. At pH 6.2, chitosan precipitated and lipids were entrapped in the formed flocculus. The binding oil was quantitatively determined, and we also demonstrate that a larger oil quantity induced less retention, while the chitosan characteristics had no influence. These observations allow us to postulate that the interaction between chitosan and oil inhibited duodenal absorption and enhanced lipid excretion.

Research paper thumbnail of Evidence on antimicrobial properties and mode of action of a chitosan obtained from crustacean exoskeletons on Pseudomonas syringae pv. tomato DC3000

Applied Microbiology and Biotechnology, 2013

Research paper thumbnail of Synthesis, characterization and evaluation of reactional parameters on substitution degree of N-hexyl-N-methylene phosphonic chitosan

Carbohydrate Polymers, 2018

Highlights  N-hexyl-N-methylene phosphonic chitosan (HNMPC) is synthesized under mild conditions... more Highlights  N-hexyl-N-methylene phosphonic chitosan (HNMPC) is synthesized under mild conditions.  The influence of reactional parameters on substitution degree was evaluated.  HNMPC was thoroughly characterized by FT-IR, 1 H, 13 C, 1 H 13 C-HSQC NMR, XRD and SEM techniques.  HNMPC forms transparent films.  Stability of emulsions evaluated makes HNMPC promising to industrial applications.

Research paper thumbnail of A simple method to quantify azo dyes in spices based on flow injection chromatography combined with chemometric tools

Journal of Food Science and Technology

Para Red (PR) and Sudan dyes have been illegally used as colorants to adulterate certain foods by... more Para Red (PR) and Sudan dyes have been illegally used as colorants to adulterate certain foods by enhancing their red/orange colour. In addition, they are toxic and carcinogenic. This work presents the development of a simple flow injection chromatographic method combined with chemometric tools to perform the determination of PR, Sudan I (SI) and Sudan II (SII) in food samples. The flow chromatographic system consisted of a low-pressure manifold coupled to a reverse phase monolithic column. A Partial Least Square (PLS) model was applied to resolve overlapped absorption spectra registered for each dye at the corresponding retention time. The relative errors of calibration (RMSECV, %) were 0.49, 0.85 and 0.23, and the relative errors of prediction (RMSEP, %) were 1.12, 0.75 and 0.33 for PR, SI and SII, respectively. The residual predictive deviation (RPD) values obtained were higher than 3.00 for all analytes. The method was successfully applied to quantify the dyes in six different commercial spices samples. The results were compared with the HPLC reference method concluding that there were no significant differences at the studied confidence level (α = 0.05). The proposed method can be used to rapidly determine the analytes in a simple, reliable, low-cost and environmentally-friendly manner.

Research paper thumbnail of Qualitative and quantitative analysis based on digital images to determine the adulteration of ketchup samples with Sudan I dye

Research paper thumbnail of Synthesis, characterization and evaluation of reactional parameters on substitution degree of N-hexyl-N-methylene phosphonic chitosan

Carbohydrate polymers, Jan 15, 2018

N-methylene phosphonic chitosan (NMPC) is treated with hexyl aldehyde to give an imine, which is ... more N-methylene phosphonic chitosan (NMPC) is treated with hexyl aldehyde to give an imine, which is easily converted into N-hexyl-N-methylene phosphonic chitosan (HNMPC) under mild conditions. The structure of this new chitosan derivative is characterized by FT- IR, H, C, P, HC-HSQC NMR, SEM and XRD. The influence of reactional parameters on the substitution degree (DS), evidenced that a mol ratio 1.50:1.00 (hexyl aldehyde: free amino groups); a reaction time of 1 h. and 45 °C of temperature afford the best DS. HNMPC molecular weight is 12,768.62 Da. It shows good emulsifying properties giving o/w emulsions with high stability in time. Microscopic observation as well as particle size distribution show an unimodal droplet size distribution with low droplet diameters. Preliminary tests lead us to believe that this new polymer has good film forming properties.

Research paper thumbnail of Chitosan as Source for Pesticide Formulations

Biological Activities and Application of Marine Polysaccharides, 2017

Late blight and wilt caused by the oomycete, Phytophthora infestans, and the fungus, Fusarium sol... more Late blight and wilt caused by the oomycete, Phytophthora infestans, and the fungus, Fusarium solani f. sp. eumartii, respectively, are severe diseases in Solanaceae crops worldwide. Although traditional approaches to control plant diseases have mainly relied on toxic chemical compounds, current studies are focused to identify more sustainable options. Finding alternatives, a low molecular weight chitosan (LMWCh) obtained from biomass of Argentine Sea's crustaceans was assayed. In an attempt to characterize the action of LMWCh alone or in combination with the synthetic fungicide Mancozeb, the antimicrobial properties of LMWCh were assayed. In a side-by-side comparison with the SYTOX Green nucleic acid stain and the nitric oxide-specific probe, diaminofluorescein-FM diacetate (DAF-FM DA), yielded a similar tendency, revealing LMWChmediated cell death. The efficacy of LMWCh, Mancozeb, and the mixture LMWCh-Mancozeb was in turn tested. A synergistic effect in the reduction of F. eumartii spore germination was measured in the presence of subinhibitory dosis of 0.025 mg ml −1 LMWCh and 0.008 mg ml −1 Mancozeb. This mixture was efficient to increase the effectiveness of the single treatments in protecting against biotic stress judged by a drastic reduction of lesion area in P. infestans-inoculated tissues and activation of the potato defense responses.

Research paper thumbnail of Antimicrobial Action of Chitosan against Spoilage Organisms in Precooked Pizza

Journal of Food Science, 2003

Chitosan antifungal capacity when the biopolymer is used as an edible film and as a dough ingredi... more Chitosan antifungal capacity when the biopolymer is used as an edible film and as a dough ingredient in precooked pizza was studied. This action was evaluated against the fungi that produce major spoilage in that product. It was observed that the use of chitosan in acetic acid as edible coating (0.079 g/100 g pizza) delayed Alternaria sp, Penicillium sp, and Cladosporium sp (Deuteromycetes) growth. This behavior was similar compared with the action of calcium propionate (0.103 g/100 g pizza) and potassium sorbate (0.034 g/100 g pizza) preservatives. On the other hand, chitosan showed a little sensibility on Aspergillus sp (Zygomycetes). It was demonstrated that the use of chitosan into the dough was not effective.

Research paper thumbnail of Relationship Between Astringency and Chitosan-Saliva Solutions Turbidity at Different pH

Journal of Food Science, 2003

The astringency stimulus perceived when chitosan is dissolved in acidic medium and the developmen... more The astringency stimulus perceived when chitosan is dissolved in acidic medium and the development of turbidity when the biopolymer interacts with saliva were investigated by sensory and chemical tests. Sensory tests showed a high correlation among the judges as astringency intensity increased when solution pH decreased. Chemical tests measured turbidity development, which decreased as pH increased until pH 4.6. When pH values were between 4.6 and 6.3, chitosan solutions interaction with saliva showed the same behavior, although with a less sharp slope of regression. Both methods demonstrated that the relationship between oral astringency and turbidity could be related to salivary protein precipitation.

Research paper thumbnail of Modified chitosan carrying phosphonic and alkyl groups

Carbohydrate Polymers, 2003

... c, Unidad de RMN, Departamento de Quı́mica Fı́sica, Facultad de Farmaci... more ... c, Unidad de RMN, Departamento de Quı́mica Fı́sica, Facultad de Farmacia, Universidad Complutense, Paseo Juan XXIII, 1-28040 Madrid, Spain. ... References. Agulló et al., 2000 Agulló, E., Ramos, V., Rodrı́guez, NM & Heras, A (2000). ...

Research paper thumbnail of Chitooligosaccharides as novel ingredients of fermented foods

Food & Function, 2015

Chitooligosaccharides can be added to yoghurt at low concentrations without affecting its nutriti... more Chitooligosaccharides can be added to yoghurt at low concentrations without affecting its nutritional composition and sensory acceptance.

Research paper thumbnail of Valoración de la eficacia de quitooligosacárido proveniente de recursos del Mar Argentino para el control de Fusarium eumartii

Fil: Mansilla, Andrea Yamila. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro ... more Fil: Mansilla, Andrea Yamila. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Mar del Plata. Instituto de Investigaciones Biologicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Biologicas; Argentina

Research paper thumbnail of The Water-Soluble Chitosan Derivative, N-Methylene Phosphonic Chitosan, Is an Effective Fungicide against the Phytopathogen Fusarium eumartii

The Plant Pathology Journal, 2021

Chitosan has been considered an environmental-friendly polymer. However, its use in agriculture h... more Chitosan has been considered an environmental-friendly polymer. However, its use in agriculture has not been extended yet due to its relatively low solubility in water. N-Methylene phosphonic chitosan (NMPC) is a water-soluble derivative prepared by adding a phosphonic group to chitosan. This study demonstrates that NMPC has a fungicidal effect on the phytopathogenic fungus Fusarium solani f. sp. eumartii (F. eumartii) judged by the inhibition of F. eumartti mycelial growth and spore germination. NMPC affected fungal membrane permeability, reactive oxygen species production, and cell death. Also, this chitosan-derivative exerted antifungal effects against two other phytopathogens, Botrytis cinerea, and Phytophthora infestans. NMPC did not affect tomato cell viability at the same doses applied to these phytopathogens to exert fungicide action. In addition to water solubility, the selective biological cytotoxicity of NMPC adds value in its application as an antimicrobial agent in agri...

Research paper thumbnail of Biodegradable films based on thermoplastic starch and chitosan with antimicrobial activity employed as active packaging

One of the research lines related to active packaging takes into account the incorporation of ant... more One of the research lines related to active packaging takes into account the incorporation of antimicrobial agents such as chitosan, a polysaccharide derived from the crustaceans' exoskeleton. However, because of chitosan high molar mass, its diffusion from the package to the food surface is restricted, so the use of oligomers is an interesting but less investigated alternative. The purpose of this work was to obtain active films based on thermoplastic corn starch (TPS) by adding oligochitosans (OC, molar mass = 290 g mol-1 and degree of polimerization = 2). Films were thermo-compressed in a hydraulic press. Diffusion assays of OC from TPS matrix to liquid medium with different acidity degree (pH = 3, 5, and 7) were performed. Liquid medium conditions were selected according to the acidity of a wide variety of foods. From these assays, oligomers diffusion capacity and the dependence with pH were demonstrated. The efficiency of OC incorporation in packaging material was compared ...

Research paper thumbnail of Película biodegradable de almidón de maíz termoplástico y quitosano con actividad antimicrobiana empleada como envase activo

Matéria (Rio de Janeiro), 2018

RESUMEN Una de las líneas para el desarrollo de envases activos contempla la incorporación de age... more RESUMEN Una de las líneas para el desarrollo de envases activos contempla la incorporación de agentes antimicrobianos como el quitosano, polisacárido derivado del exoesqueleto de crustáceos. No obstante, su elevada masa molar restringe su difusión desde el envase hacia el alimento por lo que el empleo de oligómeros de características diferenciales es una alternativa interesante, aún poco investigada. El objetivo de este trabajo fue obtener películas activas a base de almidón de maíz termoplástico (TPS) mediante la incorporación de oligoquitosanos (OQ, masa molar = 290 g mol-1 y grado de polimerización = 2). Estos materiales fueron obtenidos mediante termo-compresión en una prensa hidráulica. Se realizaron ensayos de difusión de los OQ desde la matriz de TPS hacia un medio líquido con diferentes grados de acidez (pH = 3, 5 y 7). Las condiciones del medio líquido fueron seleccionadas según la acidez de una amplia variedad de alimentos. A partir de estos ensayos, se demostró la capacid...

Research paper thumbnail of Chitosan Interaction with Iron from Yoghurt Using an In Vitro Digestive Model: Comparative Study with Plant Dietary Fibers

International Journal of Molecular Sciences, 2011

The objective of this work was to investigate the interaction of chitosan with iron from yoghurt ... more The objective of this work was to investigate the interaction of chitosan with iron from yoghurt by an in vitro gastrointestinal tract model. Taking into account that chitosan is a polysaccharide included in fiber definition by Codex Alimentarius; chitosan behavior was studied and compared with different plant fiber (wheat, bamboo, apple, psyllium and inulin) behaviors, in the same in vitro conditions. Ferrous sulfate was added to yoghurts with each type of fiber. The gastric environment was simulated with HCl (pH 1.0-2.0). The duodenal environment was simulated with NaHCO 3 (pH 6.8-7.2) and a dialysis tubing cellulose membrane. Results showed that chitosan had the highest iron retention percentages (53.2% at 30 min; 56.8% at 60 min) interacting in a more pronounced manner with iron than the plant fibers used in this work.

Research paper thumbnail of Nitric oxide-mediated cell death is triggered by chitosan in F. eumartii spores

Pest Management Science, 2014

The genus Fusarium comprises a heterogeneous group of fungi important for agriculture. Fusarium s... more The genus Fusarium comprises a heterogeneous group of fungi important for agriculture. Fusarium solani f. sp. eumartii (F. eumartii), historically considered to be a fungal pathogen of potato, has also been associated with tomato disease. Currently, chitosan and its derivatives have been receiving more attention as environmentally friendly antimicrobial compounds in sustainable practices. The aim of the present work was to characterize downstream events associated with the mode of action of chitosan, including nitrosative reactive species, in order to identify new biomarkers of its cytotoxic action. Data indicated that chitosan-mediated nitric oxide (NO) production might lead to conidial death, concomitant with the strong reduction in fungal pathogenicity in tomato plants. Following chitosan applications, a notably dose-dependent reduction in conidial viability was demonstrated in F. eumartii. Thereafter, the infectivity of chitosan-treated spores was tested by a bioassay using tomato seedlings. All these data highlight NO valuable properties as a quantitative and qualitative biomarker of cytotoxic action of chitosan in conidial cells. In addition, these findings place the chitosan assayed here as a fungicide with a high potential of application in sustainable horticultural practices. © 2014 Society of Chemical Industry.

Research paper thumbnail of Present and Future Role of Chitin and Chitosan in Food

Macromolecular Bioscience, 2003

Research paper thumbnail of Synthesis and characterization of N-propyl-N-methylene phosphonic chitosan derivative

Carbohydrate Polymers, 2010

A simple methodology for the preparation of a new chitosan derivative called N-propyl-N-methylene... more A simple methodology for the preparation of a new chitosan derivative called N-propyl-N-methylene phosphonic chitosan (PNMPC) is proposed. Introduction of a propyl chain onto a modified chitosan (N-methylene phosphonic chitosan) offers the presence of hydrophobic and hydrophilic branches for controlling solubility properties of the new derivative. Its chemical identity was determined by FT-IR, 1H, 13C and 31P NMR spectroscopy. The

Research paper thumbnail of Chitosan influence on glucose and calcium availability from yogurt: In vitro comparative study with plants fibre

Carbohydrate Polymers, 2008

... Acknowledgements. Financial support from Universidad Nacional del Sur is gratefully acknowled... more ... Acknowledgements. Financial support from Universidad Nacional del Sur is gratefully acknowledged. Marina Dello Staffolo, Miriam Martino and Alicia Bevilacqua express their gratitude to Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) Argentina. ...

Research paper thumbnail of Interaction between Chitosan and Oil under Stomach and Duodenal Digestive Chemical Conditions

Bioscience, Biotechnology, and Biochemistry, 2005

Chitosan, the N acetylated derivative of chitin, has an effect on the absorption of dietary lipid... more Chitosan, the N acetylated derivative of chitin, has an effect on the absorption of dietary lipids, but there is not enough scientific knowledge about the mechanism. To study the interaction between chitosan and oil, the action of this biopolymer has been evaluated through an experimental model of the stomach and duodenum tract, although the enzimatic activity had not been evaluated. We microscopically confirmed that chitosan in a hychloridic acid medium (pH 1.0-2.0) emulsified lipids and the emulsion was a water in oil in water type (w/o/ w). When the pH value and speed of agitation were increased to mirror the duodenum medium conditions under which lipids are absorbed, the emulsion capacity was better with an increased number of droplets and the emulsion continued as the w/o/w type. At pH 6.2, chitosan precipitated and lipids were entrapped in the formed flocculus. The binding oil was quantitatively determined, and we also demonstrate that a larger oil quantity induced less retention, while the chitosan characteristics had no influence. These observations allow us to postulate that the interaction between chitosan and oil inhibited duodenal absorption and enhanced lipid excretion.

Research paper thumbnail of Evidence on antimicrobial properties and mode of action of a chitosan obtained from crustacean exoskeletons on Pseudomonas syringae pv. tomato DC3000

Applied Microbiology and Biotechnology, 2013

Research paper thumbnail of Synthesis, characterization and evaluation of reactional parameters on substitution degree of N-hexyl-N-methylene phosphonic chitosan

Carbohydrate Polymers, 2018

Highlights  N-hexyl-N-methylene phosphonic chitosan (HNMPC) is synthesized under mild conditions... more Highlights  N-hexyl-N-methylene phosphonic chitosan (HNMPC) is synthesized under mild conditions.  The influence of reactional parameters on substitution degree was evaluated.  HNMPC was thoroughly characterized by FT-IR, 1 H, 13 C, 1 H 13 C-HSQC NMR, XRD and SEM techniques.  HNMPC forms transparent films.  Stability of emulsions evaluated makes HNMPC promising to industrial applications.

Research paper thumbnail of A simple method to quantify azo dyes in spices based on flow injection chromatography combined with chemometric tools

Journal of Food Science and Technology

Para Red (PR) and Sudan dyes have been illegally used as colorants to adulterate certain foods by... more Para Red (PR) and Sudan dyes have been illegally used as colorants to adulterate certain foods by enhancing their red/orange colour. In addition, they are toxic and carcinogenic. This work presents the development of a simple flow injection chromatographic method combined with chemometric tools to perform the determination of PR, Sudan I (SI) and Sudan II (SII) in food samples. The flow chromatographic system consisted of a low-pressure manifold coupled to a reverse phase monolithic column. A Partial Least Square (PLS) model was applied to resolve overlapped absorption spectra registered for each dye at the corresponding retention time. The relative errors of calibration (RMSECV, %) were 0.49, 0.85 and 0.23, and the relative errors of prediction (RMSEP, %) were 1.12, 0.75 and 0.33 for PR, SI and SII, respectively. The residual predictive deviation (RPD) values obtained were higher than 3.00 for all analytes. The method was successfully applied to quantify the dyes in six different commercial spices samples. The results were compared with the HPLC reference method concluding that there were no significant differences at the studied confidence level (α = 0.05). The proposed method can be used to rapidly determine the analytes in a simple, reliable, low-cost and environmentally-friendly manner.

Research paper thumbnail of Qualitative and quantitative analysis based on digital images to determine the adulteration of ketchup samples with Sudan I dye

Research paper thumbnail of Synthesis, characterization and evaluation of reactional parameters on substitution degree of N-hexyl-N-methylene phosphonic chitosan

Carbohydrate polymers, Jan 15, 2018

N-methylene phosphonic chitosan (NMPC) is treated with hexyl aldehyde to give an imine, which is ... more N-methylene phosphonic chitosan (NMPC) is treated with hexyl aldehyde to give an imine, which is easily converted into N-hexyl-N-methylene phosphonic chitosan (HNMPC) under mild conditions. The structure of this new chitosan derivative is characterized by FT- IR, H, C, P, HC-HSQC NMR, SEM and XRD. The influence of reactional parameters on the substitution degree (DS), evidenced that a mol ratio 1.50:1.00 (hexyl aldehyde: free amino groups); a reaction time of 1 h. and 45 °C of temperature afford the best DS. HNMPC molecular weight is 12,768.62 Da. It shows good emulsifying properties giving o/w emulsions with high stability in time. Microscopic observation as well as particle size distribution show an unimodal droplet size distribution with low droplet diameters. Preliminary tests lead us to believe that this new polymer has good film forming properties.

Research paper thumbnail of Chitosan as Source for Pesticide Formulations

Biological Activities and Application of Marine Polysaccharides, 2017

Late blight and wilt caused by the oomycete, Phytophthora infestans, and the fungus, Fusarium sol... more Late blight and wilt caused by the oomycete, Phytophthora infestans, and the fungus, Fusarium solani f. sp. eumartii, respectively, are severe diseases in Solanaceae crops worldwide. Although traditional approaches to control plant diseases have mainly relied on toxic chemical compounds, current studies are focused to identify more sustainable options. Finding alternatives, a low molecular weight chitosan (LMWCh) obtained from biomass of Argentine Sea's crustaceans was assayed. In an attempt to characterize the action of LMWCh alone or in combination with the synthetic fungicide Mancozeb, the antimicrobial properties of LMWCh were assayed. In a side-by-side comparison with the SYTOX Green nucleic acid stain and the nitric oxide-specific probe, diaminofluorescein-FM diacetate (DAF-FM DA), yielded a similar tendency, revealing LMWChmediated cell death. The efficacy of LMWCh, Mancozeb, and the mixture LMWCh-Mancozeb was in turn tested. A synergistic effect in the reduction of F. eumartii spore germination was measured in the presence of subinhibitory dosis of 0.025 mg ml −1 LMWCh and 0.008 mg ml −1 Mancozeb. This mixture was efficient to increase the effectiveness of the single treatments in protecting against biotic stress judged by a drastic reduction of lesion area in P. infestans-inoculated tissues and activation of the potato defense responses.

Research paper thumbnail of Antimicrobial Action of Chitosan against Spoilage Organisms in Precooked Pizza

Journal of Food Science, 2003

Chitosan antifungal capacity when the biopolymer is used as an edible film and as a dough ingredi... more Chitosan antifungal capacity when the biopolymer is used as an edible film and as a dough ingredient in precooked pizza was studied. This action was evaluated against the fungi that produce major spoilage in that product. It was observed that the use of chitosan in acetic acid as edible coating (0.079 g/100 g pizza) delayed Alternaria sp, Penicillium sp, and Cladosporium sp (Deuteromycetes) growth. This behavior was similar compared with the action of calcium propionate (0.103 g/100 g pizza) and potassium sorbate (0.034 g/100 g pizza) preservatives. On the other hand, chitosan showed a little sensibility on Aspergillus sp (Zygomycetes). It was demonstrated that the use of chitosan into the dough was not effective.

Research paper thumbnail of Relationship Between Astringency and Chitosan-Saliva Solutions Turbidity at Different pH

Journal of Food Science, 2003

The astringency stimulus perceived when chitosan is dissolved in acidic medium and the developmen... more The astringency stimulus perceived when chitosan is dissolved in acidic medium and the development of turbidity when the biopolymer interacts with saliva were investigated by sensory and chemical tests. Sensory tests showed a high correlation among the judges as astringency intensity increased when solution pH decreased. Chemical tests measured turbidity development, which decreased as pH increased until pH 4.6. When pH values were between 4.6 and 6.3, chitosan solutions interaction with saliva showed the same behavior, although with a less sharp slope of regression. Both methods demonstrated that the relationship between oral astringency and turbidity could be related to salivary protein precipitation.

Research paper thumbnail of Modified chitosan carrying phosphonic and alkyl groups

Carbohydrate Polymers, 2003

... c, Unidad de RMN, Departamento de Quı́mica Fı́sica, Facultad de Farmaci... more ... c, Unidad de RMN, Departamento de Quı́mica Fı́sica, Facultad de Farmacia, Universidad Complutense, Paseo Juan XXIII, 1-28040 Madrid, Spain. ... References. Agulló et al., 2000 Agulló, E., Ramos, V., Rodrı́guez, NM & Heras, A (2000). ...