Estudio de la interacción envase-alimento: identificación y caracterización de sustancias de partida y aditivos en envases de uso en alimentos

El envase es un elemento esencial en la conservación y comercialización de los alimentos. Además, de sus funciones primarias de contención y protección, en las últimas décadas, el envasado ha adquirido un papel esencial desde el punto de vista del marketing y de la conveniencia para el consumidor. Por una parte, los métodos modernos de marketing necesitan un envasado que comunique algo al consumidor, ya que puede decirse que en la sociedad del mundo desarrollado lo que mueve a comprar un producto es, en muchos casos, el envase y no el producto en sí. En segundo lugar, las modernas sociedades industrializadas han motivado profundos cambios en la forma de vida, y la industria del envasado ha tenido que responder a esos cambios. Por ello, en los últimos años ha ido adquiriendo gran importancia la conveniencia o utilidad de los envases (Robertson, 1993). Más allá de la simple satisfacción de las necesidades básicas, el consumidor exige productos naturales, fáciles de preparar, a ser posible que puedan ser cocinados y consumidos en el propio envase, disponibles en porciones adaptadas a sus necesidades de consumo comercializados en envases de fácil apertura, seguros, económicos, compatibles con el medio ambiente, etc

Tilapia (Oreochromis aureus) Collagen for Medical Biomaterials

Collagen is a natural polymer widely used in pharmaceutical products and nutritional supplement due to its biocompatibility and biodegradability. Collagen is a fibrous protein that supports various tissues, and its primary structure is formed by repeated units of glycine-proline-hydroxyproline. Traditional sources of collagen, such as bovine and pig skins or chicken waste, limit their use due to the dangers of animal-borne diseases. Thus, marine animals are an alternative for the extraction of collagen. The common name of Oreochromis aureus is tilapia, widely cultivated for sale as frozen fillets. During its processing, a large amount of collagen-rich wastes are generated. Therefore, the objective of this book chapter is to prove the potential of tilapia skin as an alternative source of collagen for the elaboration of biomaterials. Additionally to the literature review, experimental results of the extraction and characterization of tilapia skin collagen for use in medical dressings are presented

Overview of Electrospinned Chitosan Nanofiber Composites for Wound Dressings

Chitosan has a medical application because of its natural origin and properties of biodegradability, biocompatibility, nontoxicity, and antimicrobial capacity. Electrospinning produces non-woven nanofibers to wound dressing with high specific surface area and small pores. These properties are favorable for absorption of exudates and prevent the penetration of bacteria, thus promoting wound healing. For this reason, chitosan blends are used to produce nanofiber dressings, and the characterization of the structural, mechanical, and biological properties is very promising for further studies. Nowadays, the researchers are seeking for biomaterials that provide modern dressings with many qualities, which are designed to promote wound healing. In this chapter, the electrospinning parameters that affect the nanofiber properties based on chitosan to prepare wound dressings are highlighted

Chitosan and Xyloglucan-Based Hydrogels: An Overview of Synthetic and Functional Utility

The development of new strategies for wound healing has resulted in the design of biomedical devices using polymers of natural origin. Hydrogels are biomaterials formed by three-dimensional polymeric networks that can retain large amounts of water or biological fluids, and smooth texture similar to living tissue. Chitosan is a linear polysaccharide, (1-4)-2-amino-2deoxy-ß-D-glucan, which has desirable features such as biocompatibility, non-toxicity, hemostasis and antibacterial character. Xyloglucans have different applications in tissue engineering for their physicochemical properties, biocompatibility and control of cell expansion. Hydrogels had been made of homogeneous mixtures prepared of chitosan and purified xyloglucan, followed by a freeze-drying process to develop a flexible and porous structure. Additionally, their mechanical properties such as porosity, solubility, biodegradation, and the antibacterial activity of the hydrogels are studied. The results suggest that the incorporation of xyloglucan favors the characteristics from chitosan-based hydrogels, providing a promising alternative for application in biomaterials with antimicrobial activity

La agricultura periurbana multifuncional y sus aportaciones hacia la sustentabilidad regional en la Zona Metropolitana de Guadalajara, Jalisco, México

Un modelo de desarrollo basado en relaciones asimétricas y desequilibradas entre la ciudad y el campo, y entre la sociedad y sus ecosistemas, ha dado como resultado que en la Zona Metropolitana de Guadalajara (ZMG), en Jalisco, México, se generen conflictos ambientales en un entorno de creciente insustentabilidad regional. Algunas expresiones de esta situación se manifiestan en las áreas periurbanas y rurales con el avance descontrolado de la urbanización, la disminución de la superficie agropecuaria, la pérdida de vegetación y agrodiversidad, la deforestación, el agotamiento de los suelos, la disminución y contaminación del agua, la sanidad de los alimentos, las afectaciones a la salud pública y el deterioro del nivel de vida de sus habitantes. La importancia poblacional, económica y política de esta región y el aumento de los conflictos ambientales, demandan a los actores sociales e institucionales, la construcción de alternativas hacia la sustentabilidad regional, y en ellas juegan un papel fundamental la múltiples funciones que desempeña la agricultura periurbana o agricultura de proximidad. En este capítulo se presentan reflexiones y avances del proyecto de investigación e intervención “Agua, agrodiversidad y medio ambiente en la región Guadalajara-Chapala-Santiago” que a partir de una perspectiva de complejidad, ubicada en las ciencias de la sustentabilidad, ha realizado investigación interdisciplinaria en torno a tres procesos relevantes que generan conflictos ambientales en la región: a) uso y manejo del agua, b) relaciones ciudad campo, y c) gestión pública y social. El trabajo de intervención se ha orientado a la vinculación entre grupos y redes, a la formación campesino a campesino, al dialogo de saberes y al impulso de procesos sociales y organizativos, como parte del acompañamiento universitario a los actores locales en la construcción y fortalecimiento de sus alternativas hacia la sustentabilidad regional.ITESO, A.C

PCR Assay for Detection of Staphylococcus aureus in Fresh Lettuce (Lactuca sativa)

The growth in food demand and production growth of vegetables have led to the development of intensive production systems with the aim of having regular access to enough high‐quality food. The aim is to determine the incidence of Staphylococcus aureus in fresh lettuce by PCR in order to enhance the efficiency for detection and identification process. The Baird‐Parker method was used for isolating pathogens from 54 lettuce samples. Genomic DNA extraction was performed according the Mericon DNA Bacteria Plus Kit. The detection by PCR was performed using the pair of primers: coa gene (5′‐ATAGAGCTGATGGTACAGG‐3′ and 5′‐GCTTCCGATTGTTCGATGC‐3′). The phylogenetic tree was constructed by comparing conserved sequences from the adjacent 16S gene, using the F2C 5′‐AGAGTTTGATCATGGCTC‐3′ and C 5′‐ACGGGCGGTGTGTAC‐3′ primers. To test the antimicrobial effect, we used the disk diffusion method (Kirby‐Bauer) using Mueller‐Hinton agar and five antibiotics with different concentrations. The incidence of S. aureus was 1.7%. All the isolates were situated in the ATCC 11632 clade in accordance with other reported sequences belonging to this pathogen in the NCBI database. All the isolates seemed to be resistant to penicillin (10U). The molecular techniques used in this study are suitable for the identification of S. aureus isolated from lettuce, increasing our capability of detecting this pathogen by improving the process and increasing the efficiency contributing to the safety of this vegetable

Relationship between academic performance and use of flipped classroom: clinical cases and review of medical articles

Hoy en día las necesidades de la sociedad respecto a la formación de profesionistas se encuentran en proceso continuo de cambio y bajo un acelerado avance tecnológico, siendo prioritario cambiar el modelo tradicional de enseñanza por uno basado en las necesidades de aprendizaje de los estudiantes por lo que el modelo de aula invertida se utiliza para favorecer dicho aprendizaje utilizando trabajo coordinado por docentes y alumnos. El objetivo de este trabajo es determinar el impacto de la metodología utilizada en el rendimiento académico de los estudiantes. Es un estudio descriptivo y cuasiexperimental aplicado a 63 estudiantes de segundo año de la licenciatura de médico cirujano de la Facultad de Medicina de Tampico de la Universidad Autónoma de Tamaulipas. Los resultados muestran que el grupo donde se utilizó el aula invertida con exposición de casos clínicos obtuvo mayor rendimiento académico. Como conclusión tenemos que el aula invertida en conjunto con la exposición de casos clínicos es un modelo que permite mejorar el rendimiento académico de los estudiantes, así como lograr los objetivos de aprendizaje de la asignatura.Today the needs of society regarding the training of professionals are in a continuous process of change and under accelerated technological progress, being a priority to change the traditional teaching model for one based on the learning needs of students so that the inverted classroom model is used to favor said learning using coordinated work by teachers and students. The objective of this work is to determine the impact of the methodology used in the academic performance of the students. It is a descriptive and quasi-experimental study applied to 63 second-year students of the Medical Surgeon degree from the Tampico School of Medicine of the Autonomous University of Tamaulipas. The results show that the group where the inverted classroom was used with presentation of clinical cases obtained higher academic performance. As a conclusion, we have that the inverted classroom in conjunction with the presentation of clinical cases is a model that allows improving the academic performance of students, as well as achieving the learning objectives of the subject

Antimicrobial Activity of Chitosan Membranes Against Staphylococcus Aureus of Clinical Origin

Healthy human skin has beneficial microflora and many pathogens causing infections. Staphylococcus aureus is the most prevalent and can have multiresistance to antibiotics. Chitosan is a polysaccharide composed of glucosamine and N-acetyl-D-glucosamine, which is biodegradable and has antimicrobial activity. As part of a national scientific research project for the development and application of biomaterials, we decided to study the effect of different membranes based on chitosan against strains of S. aureus isolated from infected ulcers. The study found that seven of nine strains of S. aureus are sensitive to rifampin and the least eight of nine strains were multiresistant to more than ten antibiotics. All chitosan-based membranes confirm its antimicrobial effect on direct contact with an increase in its diameter. The contact area of the membranes is increased according to the concentration of chitosan. The highest average area increase was the chitosan membranes with honey and glycerin, 88.32%. Chitosan membranes have shown their effectiveness against S. aureus strains of clinical origin. Thus, these materials can be applied for the treatment of chronic ulcers without toxic hazards and resistance caused by antibiotics

Differences in Salivary Flow Level, Xerostomia, and Flavor Alteration in Mexican HIV Patients Who Did or Did Not Receive Antiretroviral Therapy

Objective and subjective alterations related to salivary flow have been reported in patients infected with human immunodeficiency virus (HIV), and these alterations are associated with the introduction of antiretroviral therapy. The aim of the current study was to discern whether these alterations are disease induced or secondary to drug therapy. Objective. The objective was to determine the relationships between low salivary flow, xerostomia, and flavor alterations in HIV patients who did or did not receive antiretroviral therapy. Materials and Methods. In this cross-sectional study, HIV patients were divided into two groups based on whether they had received antiretroviral therapy. Those patients with a previous diagnosis of any salivary gland disease were excluded. A survey was used to assess subjective variables, and colorimetry and salivary flow rates were measured using the Schirmer global test. Results. A total of 293 patients were included. The therapy group showed a significantly lower average salivary flow than did the group without therapy, and we observed that the flow rate tended to decrease after one year of therapy.The results were not conclusive, despite significant differences in xerostomia and flavor alteration between the groups. Conclusion. The study results suggest that antiretroviral therapy can cause cumulative damage that affects the amount of salivary flow