Development of encapsulated olive leaf extracts as innovative natural and functional food ingredients

The increasing consumer concern and demand in the last decades for foods with natural ingredients and enhanced nutritional and health-promoting properties has pushed the research in the fields of nutrition and food technology in order to find, characterize, formulate and incorporate bioactive compounds into common foods or nutraceuticals. Some of the most used food bioactives are plant phytochemicals like polyphenols present in most plants as secondary metabolites. Olive biophenols, present in most parts of the plant and found in high concentrations in the leaves, are widely recognized for their bioactive properties. Thus, olive leaves, traditionally considered as a by-product, are an abundant source of olive phenolic compounds that can be recovered and further exploited as functional ingredients in food and nutraceuticals. However, the intrinsic chemical characteristics of these and other phytochemicals compounds makes its direct use in foods very challenging. In this context, food microencapsulation has been progressively implemented to partially or totally tackle these technological and sensorial issues associated to their incorporation into foods. The large variety of bioactives (pure compounds, phenolic-rich extracts) and carriers, the specific objective of the encapsulation and the large complexity of food matrices are the reasons for the wide research and development approaches in this field. Due to the different nature of the encapsulation techniques, specific investigations on their related critical parameters and optimization of the encapsulation process and performance are needed. The investigations carried out in this work aimed to better understand the use of phenolic extracts from olive leaves by studying its chemical stability and developing encapsulated ingredients with encapsulation techniques of different nature with the potential to be used in real food matrices. Firstly, a phenolic extract from olive leaves rich in oleuropein, a well defined compound with significant health-promoting properties, was characterised in terms of thermal stability at varying pH conditions of the phenolic content, profile and radical scavenging properties, by implementing a kinetic model and also structural characterization using flurescence spectroscopy.The thermal degradation of the major component, oleuropein, followed first-order kinetics and was high at lowest pH values (pH = 2), while verbascoside appeared to be more labile at pH 6. Oleuropein hydrolysis products resulted in an increasing hydroxytyrosol concentration, that followed zero-order kinetics. These changes were also detected by fluorescence spectroscopy. On the other hand, no remarkable changes in total phenolic content and radical scavenging activity were observed. Freeze-drying was studied as a method to encapsulate olive leaf bioactives in amorphous dry carbohydrate matrices. The effect of the carrier formulation and ratio bioactive:carrier on the encapsulation efficiency, the thermal, physical and structural properties of freeze-dried microencapsulated powders was assessed by using a response surface modellig approach. Also, the impact of these factors on the chemical stability of bioactive compounds was studied. Maltodextrin and trehalose were chosen as encapsulating materials as representatives of high and low molecular weight carbohydrates with good glass forming properties for encapsulation purposes. The increasing concentration of maltodextrin enhanced the encapsulation of both total phenolics and oleuropein up to an almost total retention when maltodextrin was used alone, which could be directly observed thanks to fluorescence imaging. Color and thermal properties of the microencapsulated powders depended on the maltodextrin-trehalose ratio and a plasticizing effect of olive leaf extract was also observed, especially in the glassy powders containing maltodextrin. The storage study of unencapsulated and microencapsulated olive leaf extract powders under different physical states revealed that at least for 7 weeks, the chemical stability and antioxidant properties of the bioactives were not affected. Liposomal encapsulation of olive bioactives was investigated, first in model phospholipid membranes by evaluating the effects of oleuropein on membrane thermotropic behavior (differential scanning calorimetry) and ordering and fluidity (fluorescence polarization) in systems with passively encapsulated oleuropein (i.e., added after formation of liposomes) compared to actively encapsulated oleuropein (i.e., encapsulated during formation of liposomes). Also, the antioxidant capacity of oleuropein to inhibit lipid peroxidation. was evaluated under two types of oxidation induction. A potential food ingredient was developed by encapsulating the olive leaf extract in commercial soy phosphatidylcholine, and characterized for its morphological, physical and functional properties in model and real systems (commercial soft drink). Oleuropein and verbascoside were encapsulated with a mean efficiency of 34% and 75%, which indicated that optimization this process can be further investigated to improve the encapsulation. However, liposome encapsulation was effective for a delay of oleuropein degradation at low pH (i.e., pH 2.0), and for the maintenance of oleuropein stability over long periods at refrigeration temperatures and at different pHs. This thus shows that this lipid encapsulation indeed provides a suitable carrier in food systems, such as beverages. Finally, the antioxidant performance of olive leaf extract and other standard and plant extracts was assessed in more challenging and real food processing conditions like those commonly employed during melt-extrusion processing/encapsulation, as opposed to classical liquid antioxidant assays. A simple and novel approach has been proposed to estimate the antioxidant performance under controlled conditions using a lab-scale extruder by implementing a solid-state adaption of the crocin-bleaching liquid assay, based on the bleaching of saffron crocins

Novel dry state co-milling encapsulation of olive leaf extract

Micro-encapsulation or nano-encapsulation is nowadays representing an interesting strategy to enhance the functionality of bioactives and other biomolecules, serving several purposes such as solubility enhancement, increased gastrointestinal absorption or targeted delivery of bioactive compounds (Li et al., 2015). High energy ball milling is used in the pharmaceutical industry to produce fine dispersions or “molecular alloys” of the active ingredient in a carrier/matrix to enhance solubility and bioavailability (Bandarkar and Vavia, 2011), to produce similar solid dispersion obtained with freeze-dying or spray drying (Willart et al., 2006). Modified starch by ball milling has been applied to encapsulate β-carotene (Roa et al., 2016), but no co-milling in the dry state to encapsulate food bioactives has been implemented yet. Olive leaves phenolic compounds have been widely studied for their health promoting properties (Martín-Peláez et al., 2013) In this work, olive leaf extract (OLE) was co-milled with maltodextrin/maltodextrin-trehalose as carrier, at different ratios and milling treatment time, using a planetary ball-mill. A milling time of 60 min resulted in maximized encapsulation efficiency (95-97%). When a higher ratio of OLE to matrix was applied, encapsulation efficiency was slightly lower compared to lower ratio up to 60 min treatment, but was maximized upon longer treatment. Microstructural analysis of the highly encapsulated OLE dispersions (60-180min) using CLSM microscopy showed fine and homogeneously distributed dispersion of OLE in the internal surface of the maltodextrin/maltodextrin-trehalose matrix. Also in these samples, OLE seemed to be protected from environmental moisture/solvent compared to low encapsulated samples (0-30min) as observed during microscopy analysis. Colour analysis of powder dispersions highlights that co-milling resulted in lighter yellowish homogeneous powders as compared to non-milled, thereby masking the brownish-yellowish colour of OLE. Further experiments are needed to confirm the encapsulation and stabilization of OLE by co-milling with a carrier in order to produce stable ingredients with nutritional and health promoting potential. References BANDARKAR, F. S. & VAVIA, P. R. 2011. An optimized commercially feasible milling technique for molecular encapsulation of meloxicam in beta-cyclodextrin. Drug Dev Ind Pharm, 37, 1318-28. MARTÍN-PELÁEZ, S., COVAS, M. I., FITÓ, M., KUŠAR, A. & PRAVST, I. 2013. Health effects of olive oil polyphenols: Recent advances and possibilities for the use of health claims. Molecular Nutrition & Food Research, 57, 760-771. ROA, D. F., BUERA, M. P., TOLABA, M. P. & SANTAGAPITA, P. R. 2016. Encapsulation and Stabilization of β-Carotene in Amaranth Matrices Obtained by Dry and Wet Assisted Ball Milling. Food and Bioprocess Technology, 10, 512-521. WILLART, J. F., DESCAMPS, N., CARON, V., CAPET, F., DANÈDE, F. & DESCAMPS, M. 2006. Formation of lactose-mannitol molecular alloys by solid state vitrification. Solid State Communications, 138, 194-199

Natural History in Mexican Trades Magazines, 1840-1855

La Historia natural fue una disciplina científica cuya vertiente divulgativa tuvo un espacio importante en varias revistas de México destinadas a los grupos de artesanos del país que se publicaron en los años 1840-1855. Los escritos de esta ciencia en las páginas de dichas publicaciones periódicas constituyó uno de los probables recursos que estos lectores tuvieron para instruirse informalmente en cuestiones científicas aplicadas a su vida laboral en términos botánicos, zoológicos y mineralógicos. La lectura de los escritos naturalistas tuvo entre uno de sus fines el aprovechamiento racional y pragmático de los recursos naturales del país con fines artesanales. El periodo de estudio se caracteriza por abarcar los años previos a la fundación de la Escuela de Artes y Oficios (1856) en la ciudad de México. Los escritos de las revistas para artesanos incidieron en que en dicho establecimiento educativo se impartieran formalmente y por primera vez las cátedras científicas y técnicas que requerían los jóvenes alumnos provenientes de los gremios de artesanos de varias regiones de la república.The educational aspect of Natural History, as a scientific discipline, occupied an important place in various Mexican magazines intended for artisan groups, published in the years 1840-1855. The scientific articles in these magazines were one of the available resources for these readers to educate themselves informally in sciences which could be applied to their work, such as Botany, Zoology and Mineralogy. The reading of the naturalists’ works had, among its aims, a rational and pragmatic use of the natural resources of the country for artisans’ needs. The study period covers the years before the founding of the Escuela de Artes y Oficios (1856) in Mexico City. The articles in these trades magazines had an impact on this educational institution, as the scientific and technical subjects needed by young students from the craftsmen’s guilds of the various regions of the republic, were taught formally for the first time

Capitalismo del conocimiento: alternativas de desarrollo nacional en el software libre y de fuente abierta

La denominación de capitalismo del conocimiento como una nueva fase se fundamenta en el hecho de que a partir de la década de los ochenta del siglo XX, el conocimiento se convierte en la principal fuerza productiva, es decir, existe un incremento notable del conocimiento incorporado en la producción social. En efecto como puede observarse en la gráfica 1 se despliega la producción de nuevo conocimiento medida como número de patentes concedidas (y consecuentemente aplicadas) en la economía de Estados Unidos (eje de la izquierda). En el eje de la derecha tenemos inversión en software. El gran aumento de la participación de la inversión en software, en si una forma de conocimiento que facilita la generación de conocimientos nuevos, es otro indicador del cambio de fase. Adicionalmente, en el interior de esta industria es cada vez más importante el desarrollo del software libre (SL) y del software de fuente abierta (SFA), los cuales resultan de procesos derivados de nuevas relaciones sociales de producción que, en un sentido teóricopotencial, superan los límites impuestos por el capitalismo, y, dentro de sus límites, abren la posibilidad de vías de desarrollo con fuerte participación cognoscitiva social, lo cual puede ser aprovechado por los países en desarrollo. En lo que sigue se abordará esta problemática dividiendo la exposición en cuatro apartados: en el primero se estudia el papel crucial del software en la nueva fase de desarrollo, para en el segundo discutir las implicaciones del desarrollo del SL y el SFA en un sentido histórico para el capitalismo del conocimiento. En el tercero se estudio el desarrollo del SL y el SFA en el contexto de la reestructuración actual del sector electrónico-informático y de internet, para en el último hacer un repaso de las experiencias exitosas de la incorporación del SL y SFA en las políticas públicas de los países en desarrollo en una perspectiva de alcance o catching-up y sus implicaciones para México

The Associanism and the National Museum of Mexico´s Directive Board, 1830-1840

La Junta Directiva del Museo Nacional y el Jardín Botánico fue una asociación culta que fomentó el desarrollo de ambas instituciones científicas de la ciudad de México en la década de 1830. Particularmente, este cuerpo letrado se interesó en consolidar al Gabinete de Historia natural perteneciente al museo, como escaparate de los recursos naturales del país. Asimismo, fue partícipe de la organización, administración y reglamentación del museo, y se preocupó por que éste consiguiera una sede propia.The Board of the National Museum and the Botanical Garden was an illustrated association that promoted the development of both scientific institutions of Mexico City in the 1830s. This Board was interested in consolidate the Cabinet of Natural history belonging to the museum, as a showcase for the country's natural resources. The Board was also a participant in the organization, administration and regulation of the museum, and was interested in it got its own building.Universidad Nacional Autónoma de México IN 30381

Los establecimientos científicos de la ciudad de México vistos por viajeros, 1821-1855

Los distintos diarios y memorias de viajeros que recorrieron la ciudad de México durante la primera mitad del siglo XIX, 1821-1855, son una valiosa fuente para la historia de la práctica científica en los primeros años de vida del México independiente. ElThe different diaries and memories of travelers who visited the city of Mexico during first half of century XIX, 1821-1855, are a valuable source for the history of the scientific practice in the first years of life of independent Mexico. The developmen

Quantum reservoir computing in finite dimensions

Most existing results in the analysis of quantum reservoir computing (QRC) systems with classical inputs have been obtained using the density matrix formalism. This paper shows that alternative representations can provide better insights when dealing with design and assessment questions. More explicitly, system isomorphisms are established that unify the density matrix approach to QRC with the representation in the space of observables using Bloch vectors associated with Gell-Mann bases. It is shown that these vector representations yield state-affine systems (SAS) previously introduced in the classical reservoir computing literature and for which numerous theoretical results have been established. This connection is used to show that various statements in relation to the fading memory (FMP) and the echo state (ESP) properties are independent of the representation, and also to shed some light on fundamental questions in QRC theory in finite dimensions. In particular, a necessary and sufficient condition for the ESP and FMP to hold is formulated using standard hypotheses, and contractive quantum channels that have exclusively trivial semi-infinite solutions are characterized in terms of the existence of input-independent fixed points.Comment: 19 pages, 4 figure

Computer vision application proposal for smart inventory systems in convenience store reach-in refrigerators

Inventory systems in reach-in refrigerators employ manual or smart inventory outdated methods, although efficient, new methods like computer vision could render better results in less time, with less human intervention. The objective of this work proposes a computer vision system to acquire an inventory of products placed in reach-in convenience store refrigerators. A comparative of different computer vision object recognition models was performed to select the most appropriate model for the application. Then, based on the model characteristics and the application requirements, a YOLOv4 object recognition model was selected. Along with a 2-dimension camera positioning rig to capture a live video feed of the products to count for the inventory. Future works could include a real size prototype and further development into a commercial product.ITESO, A. C