Flavonoid and Antioxidant Capacity of Propolis Prediction Using Near Infrared Spectroscopy

[EN] The use of propolis as a dietary supplement or as an ingredient in different food products is increasing, due to its antioxidant and bactericidal properties. These nutritional properties directly depend on its phenolic composition. For this reason, this study analysed the total contents of flavones and flavonols, flavanones and dihydroflavonols, and the antioxidant capacity by using the methods of ABTS and linoleic acid/β-carotene in 99 samples of propolis from Spain and Chile. A rapid method was developed for quantifying these parameters in raw propolis using near infrared (NIR) spectroscopy with a remote reflectance fibre-optic probe applied directly to the ground-up sample. The models developed allow for the determination of the total flavones and flavonols (0–183 mg quercetin/g propolis and 0–72 mg rutin/g propolis), of the total flavanones and dihydroflavonols (9–109 mg pinocembrin/g propolis extract), and of its antioxidant capacity by the ABTS method based on the reduction of the 2.2-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation(0–3212.6 nmol Trolox/mg of propolis) and of linoleic acid/β-carotene (22–86% inhibition). The NIR spectroscopy models were applied in external validation to different samples of the calibration group, which led to the conclusion that the methods developed provide significantly identical data to the initial chemical data of reference

Integrin Signaling Regulates Spindle Orientation in Drosophila to Preserve the Follicular-Epithelium Monolayer

SummaryEpithelia act as important physiological barriers and as structural components of tissues and organs. In the Drosophila ovary, follicle cells envelop the germline cysts to form a monolayer epithelium. During division, the orientation of the mitotic spindle in follicle cells is such that both daughter cells remain within the same plane, and the simple structure of the follicular epithelium is thus preserved. Here we show that integrins, heterodimeric transmembrane receptors that connect the extracellular matrix to the cell's cytoskeleton [1, 2], are required for maintaining the ovarian monolayer epithelium in Drosophila. Mosaic egg chambers containing integrin mutant follicle cells develop stratified epithelia at both poles. This stratification is due neither to abnormal cell proliferation nor to defects in the apical-basal polarity of the mutant cells. Instead, integrin function is required for the correct orientation of the mitotic apparatus both in mutant cells and in their immediately adjacent wild-type neighbors. We further demonstrate that integrin-mediated signaling, rather than adhesion, is sufficient for maintaining the integrity of the follicular epithelium. The above data show that integrins are necessary for preserving the simple organization of a specialized epithelium and link integrin-mediated signaling to the correct orientation of the mitotic spindle in this epithelial cell type

Cooperation and governance for tourism development. Aranjuez as a case study

El artículo se basa en una investigación sobre las posibilidades de crear un órgano de gestión del destino, de carácter mixto, para la gestión turística de Aranjuez. Se argumenta que para elegir el mejor modelo de órgano de gestión turística para un destino es necesario investigar tres categorías: caracterización del turismo, importancia relativa del turismo y madurez colaborativa de los actores turísticos del destino. La conclusión es que no existe un modelo de órgano de gestión mixta que pueda ser implantado en cualquier destino turístico, siendo el contexto específico y sus condiciones los que acaban aconsejando qué tipo de institución de gestión de destino es posible diseñar e implantar.This article describes the main reflections of an investigation about the possibility to create a destination management organization for the city of Aranjuez. In order to select the best tourism destination organization for a municipal level three categories need to be investigated: characterization of the type of tourism, relative importance of tourism and collaborative maturity of the tourism stakeholders. The conclusion is that there is not one single model of a public-private management organization that can be implemented directly. The specific context and conditions of tourism destinations determine which type of destination management organization can be designed and implemented.Depto. de Ciencia Política y de la AdministraciónFac. de Ciencias Políticas y SociologíaTRUEpu

Hollow-Fiber Liquid-Phase Micro-Extraction Method for the Simultaneous Derivatization, Extraction, and Pre-concentration of Organotin Compounds from Packed Fruit Juices

Organotin compounds are widely employed as pesticides and fungicides in agriculture and as stabilizers for the industrial manufacture of polyvinyl chloride and other polymers. Accordingly, these endocrine disruptors can be found in a variety of foods and beverages. In the present study, we describe the optimization of a hollow-fiber liquid-phase micro-extraction approach for the simultaneous derivatization, extraction, and pre-concentration of butyltin species from commercial fruit juices with the aim of investigating their migration from the packaging. The best extraction efficiencies were achieved by using hexane as the acceptor solvent and a polypropylene fiber length of 2 cm, whereas the agitation speed, extraction temperature, and total extraction time were set at 1100 rpm, 25 ºC, and 10 min, respectively. Using these optimal conditions, the method was satisfactorily validated in terms of linearity (5–1000 µg L−1), limits of detection (0.8–1.8 µg L−1), recovery (80.5–92.1%), intraday precision (10.2–13.1%), inter-day precision (11.0–15.5%), matrix effect (83.2–91.8%), accuracy (85.2–95.2%), specificity, and carryover. The application of this technique to commercial samples obtained from a local market demonstrated that levels of organotin species in packed fruit juices are negligible, in agreement with the limits established by the European Food Safety Authority (0.14 mg of total organotin compounds per kg of food).Open Access funding provided by Universidad de Huelva/ CBUA thanks to the CRUE-CSIC agreement with Springer Natur