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Diseño y caracterización de microcápsulas de seleniometionina.

LILIANA VALDIVIEZO MORALES (2012)

Tesis (Maestría en Ciencias, especialista en Ganadería).- Colegio de Postgraduados, 2012.

El objetivo del presente estudio fue diseñar y caracterizar microcápsulas de liberación controlada de seleniometionina de administración vía intramamaria, con dos diferentes de tipos de agentes encapsulantes (carboximetilcelulosa de sodio (NaCMC) y alginato de sodio (/(C6H7NaO6)n)). Las microcápsulas fueron elaboradas por el método de secado por atomización; se utilizó un secador mini Spray-dryer. La caracterización morfológica de las microcápsulas fue mediante microscopía electrónica de barrido. La distribución de las partículas por tamaño para ambos sistemas se determinó con un equipo MasterSize X (1.2b MALVERN) y etilenglicol como dispersante. Se evaluó la cantidad de seleniometionina total encapsulada, el porcentaje de rendimiento, el porcentaje de recuperación, el tamaño de la partícula y la cinética de liberación de seleniometionina desde las microcápsulas; se utilizó como testigo la liberación de la seleniometionina sin encapsular a través del vehículo de entrega (carbopol 2 %). Las variables de respuesta (SeMet total encapsulada, porcentaje de recuperación y porcentaje de rendimiento) fueron significativamente diferentes, con intervalos del 95% de confianza. Las cinéticas de liberación de ambos sistemas (SeMet/NaCMC y SeMet/(C6H7NaO6)n) tuvieron un mayor ajuste al modelo matemático de Korsmeyer. La variación de n para ambos sistemas fue entre 0.5718 y 0.6064, lo que sugirió que la naturaleza del proceso de liberación de la seleniometionina fue por un mecanismo de difusión no fickiano o anómalo. Por lo tanto, el método de secado por atomización resulta una alternativa viable para elaborar microcápsulas de SeMet, además de que el agente encapsulante carboximetilcelulosa obtuvo una mayor eficiencia para el encapsulado de la seleniometionina y protegió la SeMet de la degradación térmica. Por otro lado, la carboximetilcelulosa de sodio mostró un mayor control de la entrega del activo, así como un mayor ajuste de datos a los modelos de Higuchi (1963) y Korsmeyer et al. (1983). _______________ DESIGN AND CHARACTERIZATION OF MICROCAPSULES OF SELENOMETHIONINE. ABSTRACT: The aim of this study was to design and characterize controlled release microcapsules of selenomethionine (SeMet) of intramammary administration, with two different types of encapsulating agents (sodium carboxymethylcellulose (NaCMC), and sodium alginate). The microcapsules were prepared by applying the spray drying method, using a Mini Spray-dryer. Morphological characterization of the microcapsules was made by scanning electron microscopy. The distribution of particles by size was determined for both systems with a computer MasterSize X (1.2b MALVERN) and ethylene glycol as a dispersant. We evaluated the amount of the total encapsulated selenomethionine, the yield percentage, the recovery percentage, the particle size and the release kinetics of selenomethionine from the microcapsules. We used as control the release of unencapsulated selenomethionine through the delivery vehicle (carbopol 2%). The overall response variables of encapsulated SeMet, percentage of recovery and percentage of yield were significantly different with an interval of 95% confidence. The release kinetics of both systems (SeMet/NaCMC and SeMet/(C6H7NaO6)n) had a better fit to the mathematical model by Korsmeyer. The variation of n for both the systems were between 0.5718 and 0.6064, suggesting that the nature of the release process of selenomethionine was through a diffusion mechanism not following the Fick equation neither anomalous. Therefore, the spray drying method is a viable alternative to prepare SeMet microcapsules. In addition, the encapsulating agent of SeMet resulted more efficient and protected SeMet from thermal degradation. Moreover, NaCMC showed better control of delivery of active, as well as a further data adjustment to the models of Higuchi (1963) and Korsmeyer et al. (1983).

Master thesis

Seleniometionina Microcápsulas Cinética de liberación Carboximetilcelulosa de sodio Alginato de sodio Selenomethionine Microcapsules Release kinetics Sodium carboxymethylcellulose Sodium alginate Ganadería Maestría CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA CIENCIAS AGRARIAS PRODUCCIÓN ANIMAL NUTRICIÓN

Diseño y caracterización de microcápsulas de seleniometionina

LILIANA VALDIVIEZO MORALES (2012)

Tesis (Maestría en Ciencias, especialista en Ganadería).- Colegio de Postgraduados, 2012.

El objetivo del presente estudio fue diseñar y caracterizar microcápsulas de liberación controlada de seleniometionina de administración vía intramamaria, con dos diferentes de tipos de agentes encapsulantes (carboximetilcelulosa de sodio (NaCMC) y alginato de sodio (/(C6H7NaO6)n)). Las microcápsulas fueron elaboradas por el método de secado por atomización; se utilizó un secador mini Spray-dryer. La caracterización morfológica de las microcápsulas fue mediante microscopía electrónica de barrido. La distribución de las partículas por tamaño para ambos sistemas se determinó con un equipo MasterSize X (1.2b MALVERN) y etilenglicol como dispersante. Se evaluó la cantidad de seleniometionina total encapsulada, el porcentaje de rendimiento, el porcentaje de recuperación, el tamaño de la partícula y la cinética de liberación de seleniometionina desde las microcápsulas; se utilizó como testigo la liberación de la seleniometionina sin encapsular a través del vehículo de entrega (carbopol 2 %). Las variables de respuesta (SeMet total encapsulada, porcentaje de recuperación y porcentaje de rendimiento) fueron significativamente diferentes, con intervalos del 95% de confianza. Las cinéticas de liberación de ambos sistemas (SeMet/NaCMC y SeMet/(C6H7NaO6)n) tuvieron un mayor ajuste al modelo matemático de Korsmeyer. La variación de n para ambos sistemas fue entre 0.5718 y 0.6064, lo que sugirió que la naturaleza del proceso de liberación de la seleniometionina fue por un mecanismo de difusión no fickiano o anómalo. Por lo tanto, el método de secado por atomización resulta una alternativa viable para elaborar microcápsulas de SeMet, además de que el agente encapsulante carboximetilcelulosa obtuvo una mayor eficiencia para el encapsulado de la seleniometionina y protegió la SeMet de la degradación térmica. Por otro lado, la carboximetilcelulosa de sodio mostró un mayor control de la entrega del activo, así como un mayor ajuste de datos a los modelos de Higuchi (1963) y Korsmeyer et al. (1983). _______________ DESIGN AND CHARACTERIZATION OF MICROCAPSULES OF SELENOMETHIONINE. ABSTRACT: The aim of this study was to design and characterize controlled release microcapsules of selenomethionine (SeMet) of intramammary administration, with two different types of encapsulating agents (sodium carboxymethylcellulose (NaCMC), and sodium alginate). The microcapsules were prepared by applying the spray drying method, using a Mini Spray-dryer. Morphological characterization of the microcapsules was made by scanning electron microscopy. The distribution of particles by size was determined for both systems with a computer MasterSize X (1.2b MALVERN) and ethylene glycol as a dispersant. We evaluated the amount of the total encapsulated selenomethionine, the yield percentage, the recovery percentage, the particle size and the release kinetics of selenomethionine from the microcapsules. We used as control the release of unencapsulated selenomethionine through the delivery vehicle (carbopol 2%). The overall response variables of encapsulated SeMet, percentage of recovery and percentage of yield were significantly different with an interval of 95% confidence. The release kinetics of both systems (SeMet/NaCMC and SeMet/(C6H7NaO6)n) had a better fit to the mathematical model by Korsmeyer. The variation of n for both the systems were between 0.5718 and 0.6064, suggesting that the nature of the release process of selenomethionine was through a diffusion mechanism not following the Fick equation neither anomalous. Therefore, the spray drying method is a viable alternative to prepare SeMet microcapsules. In addition, the encapsulating agent of SeMet resulted more efficient and protected SeMet from thermal degradation. Moreover, NaCMC showed better control of delivery of active, as well as a further data adjustment to the models of Higuchi (1963) and Korsmeyer et al. (1983).

Master thesis

Seleniometionina Microcápsulas Cinética de liberación Alginato de sodio Selenomethionine Carboximetilcelulosa de sodio Microcapsules Release kinetics Sodium carboxymethylcellulose Sodium alginate Maestría Ganadería CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA

Transferencia nutrimental y crecimiento de pinos neotropicales con hongos comestibles ectomicorrízicos en dos sustratos

MA. CONCEPCION RENTERIA CHAVEZ (2015)

Tesis (Maestría en Ciencias, especialista en Edafología).- Colegio de Postgraduados, 2015.

La ectomicorriza es una simbiosis mutualista de enorme importancia en la producción de árboles de interés forestal. Uno de los criterios de selección de los hongos empleados de gran interés actualmente, es su comestibilidad, por la importancia económica, ecológica y cultural de los hongos comestibles ectomicorrízicos (HCE) como un producto forestal no maderable. Se evaluó el efecto de la inoculación con 3 HCE, ampliamente comercializados en México, en el crecimiento y contenido nutrimental de Pinus greggii, crecido en un sustrato experimental, y un sustrato comercial enriquecido con un fertilizante de liberación lenta. Dos años después de la siembra, se observaron conspicuas diferencias en altura, biomasa aérea y radical y contenido de macro y micronutrimentos entre plantas inoculadas y no inoculadas, independientemente de la especie fúngica y del sustrato. A pesar de que plantas crecidas en sustrato comercial, tuvieron mayor crecimiento y contenido nutrimental, sus porcentajes de colonización fueron conspicuamente menores que plantas crecidas en sustrato experimental. Existieron evidentes diferencias en la transferencia nutrimental a la parte aérea de los pinos inoculados, entre las especies fúngicas. La transferencia de Ca por Laccaria laccata; de Na por L. bicolor y de Mn por Hebeloma leucosarx registradas en el sustrato experimental; constituyen uno de los pocos reportes conocidos de transferencia de dichos nutrimentos en gimnospermas por HCE. Se demuestra que la selección de sustratos, constituye un factor clave en la producción de plantas ectomicorrizadas y que las 3 especies de HCE evaluados tienen un enorme potencial en la producción de P. greggii. Adicionalmente se efectuaron bioensayos iniciales con Pinus patula y P. ayacahuite. _______________ NUTRIENT TRANSFER AND GROWTH OF NEOTROPICAL PINES WITH EDIBLE ECTOMYCORRHIZAL MUSHROOMS IN TWO SUBSTRATES. ABSTRACT: The ectomycorrhiza is a mutualistic symbiosis of paramount importance in the production of trees with importance in forestry. Currently, one the selection criteria of ectomycorrhizal fungi of great importance is their edibility, due to the economic, ecologic and cultural relevance of the edible ectomycorrhizal mushrooms (EEM) as a non-timber forest product. The effect of the inoculation with 3 EEM, widely sold in Mexico, on the growth and nutrient contents of Pinus greggii, grown in an experimental substrate and a commercial substrate enriched with a slow-release fertilizer, was evaluated. Two years after sowing, conspicuous differences in terms of height, shoot and root biomass and macro and micronutrient contents between inoculated and non-inoculated plants, were recorded, independently of the fungal species and the substrate. Despite the fact that plants grown in commercial substrate had higher growth and nutrient contents, their ectomycorrhizal colonization percentages were conspicuously smaller than those of plants grown in experimental substrate. Evident differences in the nutrient transfer to the inoculated plant shoots among the evaluated fungal species were recorded. Ca mobilization by Laccaria bicolor, Na by L. bicolor and Mn by Hebeloma leucosarx recorded in the plants growing in experimental substrate, constitute one of the few known reports of transference of these nutrients in gymnosperms by EEM. It is demonstrated that the selection of substrates, constitutes an important factor in the production of ectomycorrhizal plants and that the 3 evaluated species of EEM have an enormous potential in the production of P. greggii. Additionally, some preliminary bioassays with Pinus patula and Pinus ayacahuite were carried out.

Master thesis

Hongos comestibles ectomicorrízicos Biotecnología forestal Transferencia nutrimental Sodio Calcio Magnesio Edible ectomycorrhizal mushrooms Biotechnological forestry Nutrient transfer Sodium Calcium Magnesium Edafología Maestría SILVICULTURA

Molecular cloning and functional analysis of a Na + -insensitive K + transporter of Capsicum chinense Jacq

NANCY RUIZ LAU Emanuel Bojorquez Quintal BEGOÑA BENITO CASADO Ileana de la Caridad Echevarría Machado Lucila Aurelia Sánchez Cach María de Fátima Medina Lara Manuel Martínez Estévez (2019)

High-affinity K+ (HAK) transporters are encoded by a large family of genes and are ubiquitous in the plant kingdom. These HAK-type transporters participate in low- and high-affinity potassium (K+) uptake and are crucial for the maintenance of K+ homeostasis under hostile conditions. In this study, the full-length cDNA of CcHAK1 gene was isolated from roots of the habanero pepper (Capsicum chinense). CcHAK1 expression was positively regulated by K+ starvation in roots and was not inhibited in the presence of NaCl. Phylogenetic analysis placed the CcHAK1 transporter in group I of the HAK K+ transporters, showing that it is closely related to Capsicum annuum CaHAK1 and Solanum lycopersicum LeHAK5. Characterization of the protein in a yeast mutant deficient in high-affinity K+ uptake (WΔ3) suggested that CcHAK1 function is associated with high-affinity K+ uptake, with Km and Vmax for Rb of 50 μM and 0.52 nmol mg−1 min−1, respectively. K+ uptake in yeast expressing the CcHAK1 transporter was inhibited by millimolar concentrations of the cations ammonium (NH+4) and cesium (Cs+) but not by sodium (Na+). The results presented in this study suggest that the CcHAK1 transporter may contribute to the maintenance of K+ homeostasis in root cells in C. chinense plants undergoing K+-deficiency and salt stress.

Article

CAPSICUM CHINENSE HAK-TYPE TRANSPORTER K+-STARVATION POTASSIUM ROOTS SODIUM BIOLOGÍA Y QUÍMICA BIOLOGÍA Y QUÍMICA

AQUEOUS SOLUTION DISTRIBUTED SENSOR EMPLOYING P(BUTYL ACRYLATE-CO-METHYL METACRYLATE-CO-SODIUM ACRYLATE) P(BUA-MMA-C-NaA) COPOLYMERS

ALFREDO MARQUEZ LUCERO (2016)

In this work, a new sensor based on a specially designed P(butyl acrylate-co-methyl methacrylate-co-sodium acrylate P(BUA-MMA-C-NaA) copolymer, which has the following characteristics:(i) it have an anphyphylic nature, presenting a hydrophilic face grafted to an hydrophobic face; (ii) this permits to have a molecular network that avoids its dissolution in almost any liquid (polar or non-polar); (iii) the P(BUA-MMA-C-NaA) copolymer is easily processed to extrude in length continuous cables, which permits the production of actual distributed sensors of several kilometers long; (iv) also, it is straightforward synthesized by emulsion polymerization which permits to obtain inexpensively. The sensors prepared with this polymer have the following features; (i) rapid reaction to the presence of the water contained in aqueous solutions; (ii) mechanical toughness; (iii) and capacity to pinpointing leakages. The electronic system with which they work was developed with very simple technology. The production of actual distributed sensors, of several kilometers long, may survey aqueous leakages or filtrations in a number of industries as; food companies (milk, bear, wine, soft drinks), cleaning and self care products, etc.

Conference proceedings

Sodium BIOLOGÍA Y QUÍMICA QUÍMICA QUÍMICA FÍSICA OTRAS

Plants’ Challenges in a Salinized World: The Case of Capsicum

Emanuel Bojorquez Quintal ILEANA DE LA CARIDAD ECHEVARRIA MACHADO MARIA DE FATIMA MEDINA LARA MANUEL MARTINEZ ESTEVEZ (2012)

Plants are sessile and are exposed to many environmental factors and are therefore under stress. In soils used for agriculture, salinity is a major abiotic factor that affects the growth, yield and quality of crops worldwide, mainly by the accumulation of Na+ in plant tissues and resulting loss of water. Crop peppers of the genus Capsicum have a high sensitivity to stress induced by high concentrations of salts. Throughout their entire ontogeny, pepper plants are susceptible to salt stress, but damage to the seedling is more serious and results in growth retardation and even death of the seedling. Because of the economic importance of peppers, improved tolerance to salinity stress should be the primary target of research for different pepper species. For this reason, we examined the current state of research with regard to the effect of salt stress on plants of the genus Capsicum. Pants’ Challenges in a Salinized World: The Case of Capsicum.

Article

CAPSICUM SALINITY STRESS SODIUM PEPPER TRANSPORT BIOLOGÍA Y QUÍMICA

Fosfito en la solución nutritiva para el control de Phytophthora cactorum en fresa

JORGE ALBERTO GIL VALENZUELA (2012)

Tesis (Maestría en Ciencias, especialista en Edafología).- Colegio de Postgraduados, 2012.

Se establecieron plantas de fresa cv. Festival en sistema hidropónico abierto, utilizando como sustrato tezontle, con el objetivo de evaluar el efecto del fosfito en el control pre-infección de la pudrición cuerosa de la fresa ocasionada por Phytophthora cactorum. Los porcentajes del fósforo (P) total en la solución nutritiva en forma de fosfito (Phi) evaluados fueron 0, 5, 10, 15 y 20 %. Las soluciones nutritivas conteniendo Phi se suministraron una única ocasión en cinco riegos con intervalos de 1 h. Dos, cuatro y siete días después del tratamiento con fosfito, los frutos se inocularon con una solución conteniendo P. cactorum a una concentración de 105 zoosporas mL-1. La aplicación foliar de mefenoxam™ (Ridomil Gold 480 SL 45.28%) en la concentración recomendada por el proveedor se utilizó como testigo positivo en el control de P. cactorum. La incidencia de pudrición cuerosa en frutos de fresa se evaluó a los 12 días después de la inoculación de los frutos. Los resultados obtenidos muestran que los diferentes porcentajes del P total en forma de Phi en la solución nutritiva, son igualmente efectivos que mefenoxam™ para el manejo de P. cactorum en un sistema hidropónico abierto. Se observó que la adición de iones Phi en menor cantidad a las recomendadas comercialmente favorece un mejor manejo de la enfermedad, al reducir los costos de producción y contaminación al ambiente. _______________ PHOSPHITE IN THE NUTRIENT SOLUTION FOR THE CONTROL OF Phytophthora cactorum IN STRAWBERRY. ABSTRACT: Strawberry plants cv. Festival were established in an open hydroponic system, using volcanic rock as substrate, in order to evaluate the effect of phosphite (Phi) in the pre-infection management of leather rot of strawberry caused by Phytophthora cactorum. The percentages of total phosphorus (P) as Phi in the nutrient solution evaluated were 0, 5, 10, 15 and 20%. The nutrient solutions containing Phi were supplied only once in five waterings at intervals of 1 h. Two, four and seven days after treatment with Phi, fruits were inoculated with a solution containing P. cactorum at a concentration of 105 zoospores. Foliar application of mefenoxam™ (Ridomil Gold 480 SL 45.28%) in the concentration recommended by the supplier was used as positive control against P. cactorum. The incidence of leather rot in strawberry fruit was assessed 12 days after inoculation. The results show that the different percentages of total P as Phi in the nutrient solution are equally effective as mefenoxam™ in controlling P. cactorum in an open hydroponic system. We observed that the addition of Phi at lower concentrations tan those commercially recommended enables a better management of the disease, as it reduces costs of production and impacts in the environment.

Master thesis

Fragaria ananassa Pudrición cuerosa Mefenoxam Sodio Leather rot Sodium Maestría Edafología CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA

Red and brown soils increase the development and content of nutrients in habanero pepper subjected to irrigation water with high electrical conductivity

María de Fátima Medina Lara RAMON ARMANDO SOUZA PERERA Manuel Martínez Estévez MANUEL OCTAVIO RAMIREZ SUCRE Ingrid Mayanin Rodríguez Buenfil Ileana de la Caridad Echevarría Machado (2019)

The characteristics of the soil in the Peninsula of Yucatán confer unique organoleptic properties to the habanero pepper (Capsicum chinense Jacq.), and thus this entity possesses the denomination of origin of the species, making these chilis the most coveted, nationally and internationally. However, the extreme microtopographic variation distinguishing the Peninsula complicates the transfer of technologies and the successful establishment of agricultural practices. Maya farmers of the region identify the brown soils as preferable for the cultivation of this chili, although there is some controversy among the farmers regarding the best yields when the quality of the water used for irrigation is poor. No studies of the effect of soil type on this plant have been carried out. This work evaluated the impact of three types of soil of the Peninsula (red, brown, and black) on growth, fruit production, and nutrient content in soils and plants, during different phenological stages. The results indicate that the red and brown soils were the best for the growth and production of the fruit. In the black soil, it was possible to observe greater retention and accumulation of sodium applied in the water used for irrigation and in the macronutrients N, P, K, which may have led to a negative effect in the development of the fruit in these plants. Moreover, the plants growing in red and brown soils seem to make a more efficient use of the nutrients, presenting higher values of N, P, and K in their tissues in the flowering-fructification stage. These results are particularly useful in the realization of agricultural plans with a lower consumption of fertilizers, which allows an increase in yield, particularly if we take into account the enormous problems of saline intrusion worldwide and in this region.

Article

CAPSICUM CHINENSE FRUIT PRODUCTION LEPTOSOL SOILS NUTRIENT PHENOLOGICAL STAGE SALINITY SODIUM RETENTION BIOLOGÍA Y QUÍMICA CIENCIAS DE LA VIDA BIOLOGÍA MOLECULAR BIOLOGÍA MOLECULAR DE PLANTAS BIOLOGÍA MOLECULAR DE PLANTAS

Mechanisms of salt tolerance in habanero pepper plants (Capsicum chinense Jacq.): proline accumulation, ions dynamics and sodium root-shoot partition and compartmentation

Emanuel Bojorquez Quintal ANA MARIA VELARDE BUENDIA ANGELA FRANCISCA KU GONZALEZ MILDRED RUBI CARRILLO PECH DANIELA ORTEGA CAMACHO Ileana de la Caridad Echevarría Machado IGOR POTTOSIN Manuel Martínez Estévez (2014)

Despite its economic relevance, little is known about salt tolerance mechanisms in pepper plants. To address this question, we compared differences in responses to NaCl in two Capsicum chinense varieties: Rex (tolerant) and Chichen-Itza (sensitive). Under salt stress (150 mM NaCl over 7 days) roots of Rex variety accumulated 50 times more compatible solutes such as proline compared to Chichen-Itza. Mineral analysis indicated that Na(+) is restricted to roots by preventing its transport to leaves. Fluorescence analysis suggested an efficient Na(+) compartmentalization in vacuole-like structures and in small intracellular compartments in roots of Rex variety. At the same time, Na(+) in Chichen-Itza plants was compartmentalized in the apoplast, suggesting substantial Na(+) extrusion. Rex variety was found to retain more K(+) in its roots under salt stress according to a mineral analysis and microelectrode ion flux estimation (MIFE). Vanadate-sensitive H(+) efflux was higher in Chichen-Itza variety plants, suggesting a higher activity of the plasma membrane H(+)-ATPase, which fuels the extrusion of Na(+), and, possibly, also the re-uptake of K(+). Our results suggest a combination of stress tolerance mechanisms, in order to alleviate the salt-induced injury. Furthermore, Na(+) extrusion to apoplast does not appear to be an efficient strategy for salt tolerance in pepper plants.

Article

H+-ATPASEION FLUXES PEPPER POTASSIUM RETENTION PROLINE ACCUMULATION ROOTS SALT TOLERANCE SODIUM COMPARTMENTALIZATION BIOLOGÍA Y QUÍMICA BIOLOGÍA Y QUÍMICA

Chitosan–Starch–Keratin composites: Improving thermo-mechanical and degradation properties through chemical modification

CYNTHIA GRACIELA FLORES HERNANDEZ ARTURO COLIN CRUZ CARLOS VELASCO SANTOS Víctor Manuel Castaño Meneses IMELDA OLIVAS ARMENDARIZ Ana Laura Martínez Hernández (2017)

The lysozyme test shows an improved in the degradability rate, the weight loss of the films at 21 days is reduced from 73 % for chitosan-starch matrix up to 16 % for the composites with 5wt% of quill; but all films show a biodegradable character depending on keratin type and chemical modification. The outstanding properties related to the addition of treated keratin materials show that these natural composites are a remarkable alternative to potentiat-ing chitosan–starch films with sustainable features

Chitosan–starch polymers are reinforced with different keratin materials obtained from chicken feather. Keratin materials are treated with sodium hydroxide; the modified surfaces are rougher in comparison with untreated surfaces, observed by Scanning Electron Microscopy. The results obtained by Differential Scanning Calorimetry show an increase in the endothermic peak related to water evaporation of the films from 92 °C (matrix) up to 102–114 °C (reinforced composites). Glass transition temperature increases from 126 °C in the polymer matrix up to 170–200 °C for the composites. Additionally, the storage modulus in the composites is enhanced up to 1614 % for the composites with modified ground quill, 2522 % for composites with modified long fiber and 3206 % for the composites with modified short fiber. The lysozyme test shows an improved in the degradability rate, the weight loss of the films at 21 days is reduced from 73 % for chitosan-starch matrix up to 16 % for the composites with 5wt% of quill; but all films show a biodegradable character depending on keratin type and chemical modification. The outstanding properties related to the addition of treated keratin materials show that these natural composites are a remarkable alternative to potentiat-ing chitosan–starch films with sustainable features

Universidad Autónoma del Estado de México Tecnológico Nacional de México, Instituto Tecnológico de Querétaro Universidad Nacional Autónoma de México Tecnológico Nacional de México, Instituto Tecnológico de Celaya Universidad Autónoma de Cd. Juárez

Article

Chemical modification Keratin Chicken feather Sodium hydroxide Biopolymer composite BIOLOGÍA Y QUÍMICA