Extraction Systems and Analytical Techniques for Food Phenolic Compounds: A Review

Phenolic compounds are highly valuable food components due to their potential utilisation as natural bioactive and antioxidant molecules for the food, cosmetic, chemical, and pharmaceutical industries. For this purpose, the development and optimisation of efficient extraction methods is crucial to obtain phenolic-rich extracts and, for some applications, free of interfering compounds. It should be accompanied with robust analytical tools that enable the standardisation of phenolic-rich extracts for industrial applications. New methodologies based on both novel extraction and/or analysis are also implemented to characterise and elucidate novel chemical structures and to face safety, pharmacology, and toxicity issues related to phenolic compounds at the molecular level. Moreover, in combination with multivariate analysis, the extraction and analysis of phenolic compounds offer tools for plant chemotyping, food traceability and marker selection in omics studies. Therefore, this study reviews extraction techniques applied to recover phenolic compounds from foods and agri-food by-products, including liquid–liquid extraction, solid–liquid extraction assisted by intensification technologies, solid-phase extraction, and combined methods. It also provides an overview of the characterisation techniques, including UV–Vis, infra-red, nuclear magnetic resonance, mass spectrometry and others used in minor applications such as Raman spectroscopy and ion mobility spectrometry, coupled or not to chromatography. Overall, a wide range of methodologies are now available, which can be applied individually and combined to provide complementary results in the roadmap around the study of phenolic compounds

Biodiesel production from olive-pomace oil of steam-treated alperujo

Recently interest has been revived in the use of plant-derived waste oils as renewable replacements for fossil diesel fuel. Olive–pomace oil (OPO) extracted from alperujo (by-product of processed olives for olive oil extraction), and produced it in considerable quantities throughout the Mediterranean countries, can be used for biodiesel production. A steam treatment of alperujo is being implemented in OPO extraction industry. This steam treatment improves the solid–liquid separation by centrifugation and facilitates the drying for further extraction of OPO. It has been verified that the steam treatment of this by-product also increases the concentration of OPO in the resulting treated solid, a key factor from an economic point of view. In the present work, crude OPO from steam-treated alperujo was found to be good source for producing biodiesel. Oil enrichment, acidity, biodiesel yield and fatty acid methyl ester composition were evaluated and compared with the results of the untreated samples. Yields and some general physicochemical properties of the quality of biodiesel were also compared to those obtained with other oils commonly used in biodiesel production. As for biodiesel yield no differences were observed. A transesterification process which included two steps was used (acid esterification followed by alkali transesterification). The maximum biodiesel yield was obtained using molar ratio methanol/triglycerides 6:1 in presence of sodium hydroxide at a concentration of 1% (w/w), reaction temperature 60 °C and reaction time 80 min. Under these conditions the process gave yields of about 95%, of the same order as other feedstock using similar production conditions.Junta de Andalucía (P06-AGR- 01906)Dr. Guillermo Rodríguez is grateful to the JAE-Doc Programme (CSIC) co-funded by European Social Fund (Operational Programme ESF 2007-2013

Nueva cita de "Sporobolus indicus" (L.) R. Br. (Poaceae) en Andalucía occidental

A new record of Sporobolus indicus (L.) R. Br. (Poaceae) in Western AndalusiaPalabras clave. Sporobolus, Poaceae, corología, Córdoba, Andalucía Occidental, Península Ibérica.Key words. Sporobolus, Poaceae, chorology, Córdoba, Western Andalusia, Iberian Peninsula

Exploring Symmetry of Binary Classification Performance Metrics

Selecting the proper performance metric constitutes a key issue for most classification problems in the field of machine learning. Although the specialized literature has addressed several topics regarding these metrics, their symmetries have yet to be systematically studied. This research focuses on ten metrics based on a binary confusion matrix and their symmetric behaviour is formally defined under all types of transformations. Through simulated experiments, which cover the full range of datasets and classification results, the symmetric behaviour of these metrics is explored by exposing them to hundreds of simple or combined symmetric transformations. Cross-symmetries among the metrics and statistical symmetries are also explored. The results obtained show that, in all cases, three and only three types of symmetries arise: labelling inversion (between positive and negative classes); scoring inversion (concerning good and bad classifiers); and the combination of these two inversions. Additionally, certain metrics have been shown to be independent of the imbalance in the dataset and two cross-symmetries have been identified. The results regarding their symmetries reveal a deeper insight into the behaviour of various performance metrics and offer an indicator to properly interpret their values and a guide for their selection for certain specific applications.University of Seville (Spain) by Telefónica Chair “Intelligence in Networks

Isolation and identification of minor secoiridoids and phenolic components from thermally treated olive oil by-products

Documento descargado de https://digital.csic.es/handle/10261/129335The application of an industrial process based on the hydrothermal treatment of 160 °C/60 min of alperujo, a by-product of olive oil extraction, allows the formation of a liquid phase containing a high concentration of phenolic and secoiridoid compounds. Ethyl acetate was used to extract these phenolic compounds from the aqueous matrix. In this study, the isolation with polyamide and XAD resin allowed detection of the presence of phenolic compounds in minor concentrations. These minor phenols were several oleuropein derivatives that had not been identified in these phenolic extracts previously. The polar compounds, acteosides, secoiridoids, and flavonoids, that remain in the aqueous fraction after extraction with ethyl acetate were identified. We report the presence of known compounds and also detected a novel molecule in alperujo with a molecular weight of 408 whose structure was characterized for first time. This new secoiridoid glucoside was identified as 1-β-D-glucopyranosyl acyclodihydroelenolic acid.Spanish Ministry of Economy and Competitiveness AGL2013-48291-REuropean Social Fund (ESF) AGL2013-48291-

Versatile protein-templated TiO2 nanocomposite for energy storage and catalytic applications

A protein-templated titania nanocomposite (PT-TiO2) was successfully synthesized by a water-free mechanochemical approach. A biomass valorization strategy was developed by employing egg white from expired eggs to control the morphology and textural features of the prepared titania. A remarkable enhancement of the surface area was achieved, in comparison with the synthesis of the material in absence of the biomass-derived template. Several techniques, such as scanning electron microscopy-mapping and CNHS analysis, supported the presence of carbon, nitrogen and sulfur residues in the obtained composite. Catalytic performance of PT-TiO2 was explored in the oxidation of diphenyl sulfide, displaying promising results in terms of conversion, selectivity and stability. The effect of the oxidant agent was additionally investigated by using hydrogen peroxide, urea hydrogen peroxide, oxygen and t-butyl-hydroperoxide. On the other hand, PT-TiO2 nanocomposite was successfully proved as anodic material for lithium-ion batteries delivering a reversible capacity of 107 mAh g–1 at 0.1C with an excellent Coulombic efficiency of 100% from the second cycle. In addition, the as-synthesized material showed significant capacity retention values of 76% among the 2nd cycle and 100th cycle. PT-TiO2 resulted to be a versatile material with potential catalytic and energy storage applications

Procedimiento de purificación de 3,4-dihidroxifenilglicol (DHFG) a partir de productos vegetales

Procedimiento de purificación de 3,4-dihidroxifenilglicol (DHFG) a partir de productos vegetales. Procedimiento de purificación de 3,4-dihidroxifenilglicol (DHFG) a partir de cualquier parte de la planta, productos o subproductos derivados del olivo o cualquier otro producto vegetal de la familia Oleaceae, Orobanchaceae, Plantaginaceae, Compositae, Lamiaceae, Acanthaceae y/o Scrophulariaceae, y que comprende 1 o más etapas en las que se introduce el producto inicial en al menos una columna de resina iónica, en posibles posteriores etapas se introduce el producto eluido en la columna anterior en una columna de resina iónica y/o de resina de adsorción no iónica. Además, se refiere al extracto de DHFG obtenible mediante el procedimiento descrito y a sus aplicaciones.Peer reviewedConsejo Superior de Investigaciones Científicas (España)B1 Patente sin examen previ