Effects of Solar Drying on the Structural and Thermodynamic Characteristics of Bee Pollen / Efectos del secado solar sobre las características estructurales y termodinámicas del polen apícola

Background: Bee pollen is a natural product collected and transformed by bees, intended for human consumption, given its nutritional and bioactive richness. The fundamental operation of adequacy is drying, which allows its preservation, avoiding chemical or microbiological degradation, typically using tray dryers with hot air that use electricity or fuel for heat generation. Solar drying is an alternative that uses radiation as an energy source. However, it should be ensured that this type of process guarantees the quality of the product while not degrading its properties and, therefore, maintaining its morphological integrity. Objective: to establish the effect of solar drying on bee pollen structure compared to the conventional cabin dehydration process. Methods: Bee pollen was dehydrated using two types of dryers: a solar dryer and a forced convection oven. The solar dryer operating conditions were an average temperature of 19-35 °C with a maximum of 38 °C and average relative humidity (RH) of 55 %. Cabin dryer operating conditions were a set point temperature of 55 ± 2 °C and 10 % RH average humidity. The morphologic and thermodynamic properties of dried bee pollen, such as phase transition enthalpy through Differential Scanning Calorimetry (DSC), porosity and surface area through surface area analysis, and microscopic surface appearance by Scanning Electron Microscopy (SEM), were measured. Results: The results showed dry bee pollen, both in the cabin dryer and solar dryer, did not suffer morphological changes seen through SEM compared to fresh bee pollen. Moreover, surface area analysis indicated the absence of porosity in the microscopic or macroscopic structure, demonstrating that solar or cabin drying processes did not affect the specific surface area concerning fresh bee pollen. Additionally, Differential Scanning Calorimetry (DSC) and Thermo Gravimetric Analysis (TGA) showed that endothermic phase transitions for dried bee pollen by cabin or solar dryer were at 145 °C and 160 °C, respectively. This can be mostly associated with free water loss due to the morphological structure preservation of the material compared to fresh bee pollen. Conclusion: These results demonstrate that solar drying is a reliable alternative to bee pollen dehydration as there were no effects that compromised its structural integrity

Antecedentes: El polen apícola es un producto natural recolectado y transformado por las abejas. La operación fundamental de adecuación del polen es el secado, lo que permite su conservación, evitando su degradación química o microbiológica, típicamente se utilizan secadores de bandejas con aire caliente que emplean electricidad o combustibles para la generación de calor. El secado solar es una alternativa que utiliza la radiación solar como fuente de energía. Sin embargo, se debe garantizar que este tipo de proceso asegure la calidad del producto a la vez que no degrade sus propiedades, manteniendo su integridad morfológica. Objetivo: Establecer el efecto del secado solar sobre la estructura del polen apícola en comparación al proceso convencional de deshidratación en cabina. Métodos: El polen de abeja se deshidrató utilizando dos tipos de secadores: secador solar y horno de convención forzada. Las condiciones de operación del secador solar fueron una temperatura promedio de 19-45 °C con un máximo de 38 °C y una humedad relativa (HR) promedio de 55 %. Las condiciones de operación del secador de cabina fueron una temperatura de referencia de 55 ± 2 °C y una humedad promedio de 10 % HR. Se midieron las propiedades morfológicas y termodinámicas del polen de abeja desecado, como la entalpía de transición de fase mediante calorimetría diferencial de barrido (DSC), la porosidad y el área superficial mediante análisis de área superficial y el aspecto microscópico de la superficie mediante microscopía electrónica de barrido (SEM). Resultados: Los resultados mostraron que el polen seco tanto en el secador de cabina como en el secador solar muestra que no sufrió cambios morfológicos vistos a través de Microscopía Electrónica de Barrido y en comparación con el polen fresco de abeja, además un análisis de sortometría indicó la ausencia de porosidad en la estructura microscópica y macroscópica, lo que indica que los procesos de secado solar o en cabina no tuvieron efectos sobre el área superficial específica con respecto al polen fresco de las abejas. En adición, los resultados de calorimetría diferencial de barrido (DSC) y análisis termogravimétrico (TGA) muestran que las transiciones de fase endotérmicas para el polen seco tanto en secado de cabina como solar fueron a 145 °C y 160 °C, que puede asociarse mayormente a la pérdida de agua libre, debido a la conservación de la estructura morfológica del material y en comparación al polen fresco. Conclusión: Estos resultados demuestran que el secado solar es una alternativa viable para la deshidratación del polen al no existir efectos que comprometan su integridad estructural

Índices de calidad de habitat y macroinvertebrados en siete Cuencas del Parque Nacional Yanachaga Chemillén y su Zona de Amortiguamiento: conservación y manejo del bosque ribereño en el Perú / Habitat quality indexes y macroinvertebrates in seven Basins of the Yanachaga Chemillén National Park and its Buffer Zone: conservation and management of the riparian forest in Peru

Resumen Se presenta la caracterización del ambiente acuático, el ecosistema ribereño y las comunidades de macroinvertebrados en siete cuencas del flanco oeste del Parque Nacional Yanachaga Chemillén (PNYCh). Se aplicó el protocolo CERA que incluye el Índice Biótico Andino (IBA), el Índice de Hábitat Fluvial (IHF), el Índice de quebrada Andina (Qbr-And) y la combinación de los tres índices para determinar el Índice de Estado Ecológico de Ríos Andinos (ECOSTRIAND) en cada punto de muestreo. Asimismo, se estimaron los índices FBI y BMWP-Col para comparar la calidad de agua. Los muestreos se realizaron en las siete cuencas, entre los 1800 y los 2500 m de altitud, en la parte alta dentro del PNYCh, y en las cuencas media y baja, ambas en la zona de amortiguamiento del PNYCh. En las cuencas evaluadas se colectaron 179 taxa, 66 familias y 14 órdenes. Dentro del PNYCh los valores de IHF y Qbr-And fueron óptimos y en general fueron disminuyendo en calidad al alejarse del PNYCh. El IBA fue muy bueno en todas las cuencas y en todos los puntos de muestreo. Sin embargo, al combinar los 3 índices se observó una disminución del estado ecológico (ECOSTRIAND) de Muy bueno a Bueno y Regular. Los resultados finales muestran que el índice de estado ecológico disminuye al alejarse del PNYCh y esto coincide con un mayor disturbio de los bosques ribereños. Por último, se discute la protección legal de este tipo de ecosistemas ribereños en varios países de América y específicamente en Perú.

Abstract We present the characterization of the aquatic environment, riparian ecosystem and macroinvertebrate communities in 7 basins of the west slope of the Yanachaga Chemillén National Park (PNYCh). The CERA protocol, including the Andean Biotic Index (ABI), the Fluvial Habitat Index (IHF), the Andean Creek Index (Qbr-And) were estimated and the combination of these 3 indexes allowed to calculate the Ecological Status Index of Andean Rivers (ECOSTRIAND) at each sampling point. Additionally the FBI and BMWP-Col indexes were calculated. Sampling was carried out in the 7 basins, between 1800 and 2500 meters of altitude, including the upper basins inside the PNYCh, in the middle and lower basins, both in the buffer zone of the park. We found 179 taxa, 66 families and 14 orders in all basins evaluated. Within the PNYCh, the values of IHF and Qbr-And were optimal, but to go down basins, the indexes generally were decreasing in quality. The IBA was very good in all basins and all sampling points. However, when the 3 indexes were combining, the ECOSTRIAND index decreased, changed from very good to good and regular in some basins. The final results show that the ecological status index decreased as it moves away from PNYCh, this is associated with a greater riparian forests disturbance. Finally, we discussed the legal protection of this type of forest in several countries of America and specifically in Peru

Design and synthesis of biologically active peptides: a 'tail' of amino acids can modulate activity of synthetic cyclic peptides.

In earlier work, we synthesized a cyclic 9-amino acid peptide (AFPep, cyclo[EKTOVNOGN]) and showed it to be useful for prevention and therapy of breast cancer. In an effort to explore the structure-function relationships of AFPep, we have designed analogs that bear a short 'tail' (one or two amino acids) attached to the cyclic peptide distal to its pharmacophore. Analogs that bore a tail of either one or two amino acids, either of which had a hydrophilic moiety in the side chain (e.g., cyclo[EKTOVNOGN]FS) exhibited greatly diminished biological activity (inhibition of estrogen-stimulated uterine growth) relative to AFPep. Analogs that bore a tail of either one or two amino acids which had hydrophobic (aliphatic or aromatic) side chains (e.g., cyclo[EKTOVNOGN]FI) retained (or had enhanced) growth inhibition activity. Combining in the same biological assay a hydrophilic-tailed analog with either AFPep or a hydrophobic-tailed analog resulted in decreased activity relative to that for AFPep or for the hydrophobic-tailed analog alone, suggesting that hydrophilic-tailed analogs are binding to a biologically active receptor. An analog with a disrupted pharmacophore (cyclo[EKTOVGOGN]) exhibited little or no growth inhibition activity. An analog with a hydrophilic tail and a disrupted pharmacophore (cyclo[EKTOVGOGN]FS) exhibited no growth inhibition activity of its own and did not affect the activity of a hydrophobic-tailed analog, but enhanced the growth inhibition activity of AFPep. These results are discussed in the context of a two-receptor model for binding of AFPep and ring-and-tail analogs. We suggest that tails on cyclic peptides may comprise a useful method to enhance diversity of peptide design and specificity of ligand-receptor interactions.