Resumen En este trabajo se elaboraron películas comestibles (PCs) a base de quitosano (Q), agar (A) y tomillo (T), en cuatro diferentes formulaciones (Q, A, QA y QAT). A las PCs se les evaluaron propiedades mecánicas (tensión y elongación a la ruptura), propiedades estructurales (espectroscopía de infrarrojo por FTIR), propiedades térmicas (análisis termogravimétrico), propiedades de transporte (permeabilidad al vapor de agua) y análisis morfológico (microscopía electrónica de barrido). Las PCs de QA y QAT destacaron por su resistencia a la tensión, transparencia, velocidad de transmisión al vapor de agua y permeancia, así como la mayor capacidad antio-xidante. Se evaluó el efecto de la aplicación de los recubrimientos comestibles (RCs) de QA y QAT en la calidad de frutos de aguacate “Hass” durante 13 días de almacenamiento a 25 °C. Se evaluaron periódicamente en los frutos las variables de pérdida de peso, tasa de respiración, producción de etileno, apariencia visual y pudriciones. La aplicación de los RCs al fruto redujo su pérdida de peso y extendió su vida de anaquel. Los RCs les confirieron a los frutos una barrera al vapor de agua, reduciendo la pérdida de peso en 40%. Así mismo, se disminuyó la incidencia de pudriciones de los frutos.

Abstract In this work, edible films (PCs) based on chitosan (Q), agar (A) and thyme oil (T) were prepared in four different formulations (Q, A, QA and QAT), and their mechanical properties (tension and elongation at break) and water vapor permeability were evaluated. Infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) were also performed. The QA and QAT PCs stood out for their tensile strength, transparency, water vapor transmission rate and permeance, as well as the highest antioxidant activity. The effect of the application of the edible coatings (RCs) of QA and QAT on the quality of ‘Hass’ avocado fruit was evaluated during 13 d of storage at 25 °C. The following variables were evaluated periodically: weight loss, respiration rate, ethylene production, visual appearance, and rotting. The application of RCs to the fruit reduced their weight loss and extended their shelf life. The RCs gave the fruit a barrier to water vapor, reducing weight loss by 40 with respect to the control. In addition, the incidence of fruit rots was reduced.

Abstract Biomaterials developed with biopolymers contribute to the healing process of healthy or diabetic patients. The objective of the present study was to evaluate the effect of honey incorporation (0.3, 0.6, and 1.2 g/100 mL) in chitosan/collagen/glycerol composite films. The Ch/Coll/1.2H films revealed the greatest percentage of elongation (27.10%) and Young´s modulus (65.58 MPa). The barrier properties (WVTR and WVP) exhibited a significant increase when the honey was incorporated into the films. The absorption capacity, solubility, and enzymatic biodegradability were lower in films containing honey. The chemical interactions between the functional groups of the films were verified by FTIR. The morphology studied by SEM confirmed the mixture’s homogeneity. Finally, all formulations exhibited antibacterial properties against Staphylococcus aureus, Pseudomonas aeruginosa, Listeria monocytogenes, and Salmonella Typhimurium. The aforementioned properties of formulated dressings are suitable for their potential application in chronic wounds.

Abstract Coconut pulp and coconut oil are valued for their health effects, these properties are attributed to bioactive compounds, such as lauric, myristic and palmitic acid mainly, phenolic compounds and vitamin E. The concentration of these compounds depends on the cultivar, the conditions biotic and abiotic of the growing area. In this study, the effect of the cultivar and producing areas was determined on the physicochemical characteristics (weight, endosperm thickness, pH, total soluble solids, humidity), and bioactive compounds in coconut and its oil. Physicochemical properties and bioactive compounds such as total phenols, (-tocopherol and the fatty acid profile were analyzed; in the cultivars harvested in the state of Guerrero (Alto Pacífico-saladita, Enano Verde, and Híbrido) and in Yucatán (Alto Pacífico-2 and Enano Verde). The analyzed physicochemical properties and the bioactive compounds are different depending on the cultivar and the cultivation region. The cultivar Enano Verde from Yucatán is superior in the content of phenolic compounds (767.44 mg gallic acid / 100 g), while Alto Pacífico-Saladita in α-tocopherol (151.03 µg/100 g). The type of cultivar could be directly influencing the physicochemical characteristics and the bioactive compounds studied.

Resumen La pulpa y aceite de coco son valorados por los efectos sobre la salud, estas propiedades son atribuidas a compuestos bioactivos, como el ácido láurico, mirístico y palmítico principalmente, compuestos fenólicos y vitamina E. La concentración de estos compuestos depende del cultivar, las condiciones bióticas y abióticas de la zona de cultivo. En este estudio se determinó el efecto del cultivar y zonas productoras, sobre las características fisicoquímicas (peso, espesor del endospermo, pH, sólidos solubles totales, humedad) y compuestos bioactivos en el coco y su aceite. Se analizaron las propiedades fisicoquímicas y los compuestos bioactivos como fenoles totales, (-tocoferol y el perfil de ácidos grasos; en los cultivares cosechados en el estado de Guerrero (Alto Pacífico-saladita, Enano Verde, e Híbrido) y en Yucatán (Alto Pacífico-2 y Enano Verde). Las propiedades fisicoquímicas y los compuestos bioactivos analizados, son diferentes dependiendo del cultivar y la región de cultivo. El cultivar Enano Verde de Yucatán, es superior en el contenido de compuestos fenólicos (767.44 mg ácido gálico/100 g), mientras que Alto Pacífico-Saladita en α-tocoferol (151.03 µg/100 g). El tipo de cultivar podría estar influyendo directamente en las características fisicoquímicas y los compuestos bioactivos estudiados.

Abstract Objective: to develop a prospective of coconut production in Yucatán. Methodology: a documentary research was carried out and surveys and interviews were applied to coconut producers and other actors in the coconut-producing regions in Yucatán. Results: the recovery of coconut production in Yucatán has been very slow, because after the devastation caused by the lethal yellowing disease; production actors were left disjointed and disorganized. Furthermore, there was a lack of integrated exploitation, lack of government financial credits or private economical support. However, there are scientific developments in the state, which can contribute to the creation of productive plantations. Limitations: the field work was carried out in at least one municipality of each producing region, choosing those with the highest production. Value: the current production was analyzed and a prospective of possible scenarios was developed. Conclusions: it is important to create links between producers, the academy, and government, to give coconut conservation and use training, and promote public policies to minimize production chain weaknesses and maximize opportunities for producers.

Resumen Objetivo: realizar una prospectiva de la producción de coco en Yucatán. Metodología: se llevó a cabo una investigación documental y se efectuaron encuestas y entrevistas a productores y a otros actores de las regiones productoras de coco de Yucatán. Resultados: la recuperación de la producción del fruto en el estado ha sido muy lenta, porque después de la devastación que causó la enfermedad del amarillamiento letal del cocotero, los actores quedaron desarticulados y desorganizados. Además, hubo escaso aprovechamiento integral de la fruta, falta de créditos del gobierno o apoyos económicos privados. No obstante, en el estado hay desarrollos científicos que pueden contribuir a la creación de plantaciones productivas. Limitaciones: el trabajo de campo se realizó en al menos un municipio por cada región productora. Se seleccionaron aquellos que tenían mayor producción. Valor: se analizó la actual producción y se hizo una prospectiva de los escenarios posibles. Conclusiones: es importante la creación de vínculos entre productores, académicos y gobierno, dar capacitación sobre el aprovechamiento integral del fruto e impulsar políticas públicas para minimizar las debilidades de la cadena de producción y maximizar las oportunidades para los productores.

Resumen La Moringa oleífera (MO) es una especie arbórea nativa del sur del Himalaya, India, Bangladesh, Afganistán y Pakistán, utilizada comercialmente para producir té, forraje para animales y medicinas herbales. El objetivo del presente estudio fue determinar las características nutricionales de diferentes partes de la planta de MO provenientes de dos regiones de México (Estados de Guerrero y Sonora). Los análisis de composición proximal (lípidos, proteínas, cenizas y fibra) se realizaron en base a las metodologías establecidas por la Asociación de Químicos Analíticos Oficiales (AOAC), y la determinación de capacidad antioxidante y compuestos fenólicos se realizó por métodos espectrofotométricos. Los contenidos de proteínas (38.5%) y lípidos (42.2%) de las semillas de MO fueron los más altos en comparación con otras partes de la planta. Estos resultados fueron similares entre las dos regiones de México que fueron evaluadas. Las flores de MO de Guerrero mostraron el mayor contenido de fenoles y taninos (1908.71 mg Equivalentes de Ácido Gálico (EAG) 100 g-1, 220.27 mg Equivalentes de Catequina (EC) 100 g-1, respectivamente) mientras que las hojas MO de Sonora mostraron el mayor contenido de flavonoides (2859 mg EAG 100 g-1). El análisis de Capacidad Antioxidante Equivalente de Trolox (CAET) mostró que las cáscaras de MO obtenidas en la región de Guerrero tienen la mayor capacidad antioxidante (224.45 μmol Equivalentes de Trolox (ET) g-1). La prueba de Capacidad de Absorción de Radicales de Oxígeno (CARO) señaló que las flores de MO de Guerrero tienen la mayor capacidad antioxidante (382 μmol ET g-1). La diferencia entre el MO de las dos regiones diferentes reportadas en este estudio podría atribuirse a factores como el tipo de suelo, las condiciones climáticas y la región de siembra.

Abstract Moringa oleifera (MO) is a native tree species found in the south of the Himalayas, India, Bangladesh, Afghanistan and Pakistan that is used commercially to produce tea, animal fodder and herbal medicines. The aim of the present study was to determine the nutritional characteristics of different parts of the MO plant from two regions of Mexico (States of Guerrero and Sonora). The proximal composition analyses (protein, lipids, ashes and fiber) were carried out according to the methods of the Association of Official Analytical Chemists (AOAC), and the antioxidant capacity and phenolic compounds were determined by spectrophotometric methods. Protein (38.5%) and lipid contents (42.2%) were higher in MO seeds compared to other plant parts. These results were similar between the two regions of Mexico that were evaluated. MO flowers from Guerrero showed the highest content of phenols and tannins (1908.71 mg Gallic Acid Equivalents (GAE) 100 g-1, 220.27 mg Catechin Equivalents (CE) 100 g-1, respectively) while MO leaves from Sonora showed the highest flavonoid content (2859 mg GAE 100 g-1). The Trolox Equivalent Antioxidant Capacity (TEAC) analysis showed that MO husks obtained from Guerrero had the highest antioxidant capacity (224.45 μmol Trolox Equivalents (TE) g-1). The Oxygen Radical Absorbance Capacity (ORAC) test showed that MO flowers from Guerrero had the highest antioxidant capacity (382 μmol (TE) g-1). The differences between MO from the two different regions reported in this study could be attributed to factors such as soil type, climatic conditions and the growing region.

Abstract Electrospun nanofibers from gelatin (G), chitosan (CS), and chitosan-polyvinyl alcohol (CS-PVA) were developed by electrospinning process. Mechanical properties were determined by the tensile test, the elastic modulus values of the nanofibers were G (15.418-34.34 MPa) and CS-PVA (17.44-126.427 MPa). The morphological characterization by SEM revealed that the systems with 15% G and 6% CS-PVA showed morphological homogeneity. Structural characterization by FTIR indicated an interaction among some functional groups of the component. Thermal analysis by DSC and TGA showed degradation temperatures for G (330 °C), CS (210 °C to 370 °C), and PVA (310 °C to 420 °C). The contact angles values denoted the hydrophilic nature of the material. Finally, the antimicrobial assay proved that both 15% G and 7% PVA on the CS-PVA system presented the best antimicrobial effect. The results indicate that the electrospun nanofibers fabricated with G or CS-PVA can be used as wound healing dressings.

Abstract The use of agroindustry waste is an option that benefits the environment. During the production of products with woven jute fibers (WJF) fragments are generated which do not have a specific use. In this work, we propose the use of WJF residues as a reinforcing material in laminates of polylactic acid (PLA) as an ecological and sustainable alternative to obtain low cost biodegradable biocomposites that can replace petroleum plastics. In order to improve the WJF and PLA compatibility, physicochemical treatments were used in fibers such as gamma irradiation (GI) and functionalization with maleic anhydride (MA). The results of PLA/WJF (MA) biocomposites revealed improvements in the mechanical and thermal properties compared to neat PLA; with an increase in elastic, flexural and storage modules of 48%, 6%, and 23%, respectively. This opens up the possible application of PLA/ WJF biocomposites in rigid containers, as well as the way to take advantage of other natural fibers used locally.

Resumen El aprovechamiento de residuos agroindustriales es una opción que beneficia al medio ambiente. Durante la elaboración de productos con fibras tejidas de yute (FTY) se generan fragmentos, los cuales no tienen un uso específico. En este trabajo, se propone la utilización de residuos de FTY como material de refuerzo en láminas de ácido poliláctico (PLA), como una alternativa ecológica y sustentable de obtener biocompuestos biodegradables a bajo costo que puedan sustituir a los plásticos provenientes del petróleo. Con el objetivo de mejorar la compatibilidad de las FTY y el PLA se utilizaron tratamientos fisicoquímicos en las fibras como la irradiación gamma (IG) y la funcionalización con anhídrido maleico (AM). Los resultados de los biocompuestos de PLA/ FTY (AM) revelaron mejoras en las propiedades mecánicas y térmicas comparadas con el PLA puro; con un incremento en los módulos elástico, de flexión y almacenamiento del 48%, 6% y 23 %, respectivamente. Esto entreabre la posible aplicación de los biocompuestos de PLA/FTY en envases rígidos, así como el camino para el aprovechamiento de otras fibras naturales usadas localmente.

ABSTRACT The ethanolic extract of Melipona beecheii Bennett 1831, propolis from Yucatán Mexico was evaluated in vitro for the determination of its phenolic compound content, antioxidant capacity and antifungal activity. The results were compared against those of the ethanolic extract of Apis mellifera propolis. The total phenolic content, flavonoid content and flavanones–dihydroflavonols content were assessed by colorimetric methods. The antifungal activity was assessed in vitro against Candida albicans. For the ethanolic extract of M. beecheii propolis; total phenolic content, was 263.25 ± 8.78 µg/ml, total flavonoid content was 768 ± 204 µg/ml and flavanones–dihydroflavonols content was 335.42 ± 15.08 µg/ml. For antioxidant activity assessed as DPPH scavenging and iron reducing power ethanolic extract of M. beecheii propolis reported IC50 of 32.47 and 1.60 µg/ml of gallic acid equivalent respectively. Regarding antifungal activity against C. albicans, the minimal inhibitory concentration and minimal fungicidal concentration for ethanolic extract of M. beecheii propolis were 1.62 ± 0.33 and 2.50 ± 0.22 µg/ml of dry extract; For both minimal inhibitory concentration and minimal fungicidal concentration, ethanolic extract of M. beecheii propolis required 30% less concentration of dry extract than ethanol extract of A. mellifera propolis to exert the same antifungal actions against C. albicans. To the best of our knowledge, this is the first report about the flavonoid and flavanones–dihydroflavonols content of M. beecheii propolis. Due to the lack of information available about the stingless bee's honeycomb products, the study and conservation of endemic honeybees should remain as an active focus of research.