Evaluación de la homogeneización por microcanales para la preparación y caracterización de emulsiones submicrónicas de aceites esenciales

This Ph.D. Thesis is a contribution to gain a deeper insight into the formulation and processing of submicron essential oil emulsions, using a novel bio-based surfactant derived from wheat biomass. Thyme and rosemary oil emulsions were prepared by microchannel homogenization, based on the microfluidization technique. They were characterized by assessing their physical stability, rheological and microstructural properties.Esta Tesis Doctoral es una contribución a los avances en formulación y procesado de emulsiones de aceites esenciales con diámetros medios de gota submicrónicos, utilizando un nuevo tensioactivo derivado de la biomasa del trigo. Se han preparado emulsiones de aceite de tomillo y romero mediante la técnica de homogeneización por microcanales, basada en la tecnología de microfluidización. Estas emulsiones se han caracterizado evaluando sus propiedades de estabilidad física, reología y microestructura

Elaboration and characterization of nanoemulsion with orange essential oil and pectin

BACKGROUND: Nanoemulsions formulated with citric essential oils are currently of interest because of their physical and chemical properties and multiple applications in areas such as the food industry or agrochemicals. These are thermodynamically unstable and have almost Newtonian flow behaviour, but a suitable formulation allows systems to be obtained with good physical stability and rheological properties. The addition of pectin makes this possible. In this work, food nanoemulsions formulated with pectin, orange essential oil (5 wt%), and Tween 80 were obtained by microfluidization. First, the effect of Tween 80 concentration from 1 to 5 wt% on emulsions without pectin was evaluated. Then, pectin was added to the most stable nanoemulsion obtained and two variables were studied: the pectin solution concentration (from 2 to 6 wt%) and the pectin/emulsion ratio (1:1 or 2:1) at a fixed pectin concentration. RESULTS: Rheological, laser diffraction, and multiple light scattering techniques were employed to determine the content of Tween 80 that results in the most stable nanoemulsion without pectin, which was 3 wt%. In addition, these techniques were used to determine the structure and physical stability of the nanoemulsions containing orange essential oil and pectin. The results obtained showed that the emulsions containing 2 wt% pectin were destabilized before 24 h. Furthermore, the emulsion with 6 wt% pectin and a 2:1 pectin/emulsion ratio showed the highest viscosity and the lowest mean diameters, and therefore the greatest stability. CONCLUSION: This work extends the knowledge of formulation of nanoemulsions and using essential oils. © 2021 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.Ministerio de Economía y Competitividad CTQ2015-70700-

Influence of nanoemulsion/gum ratio on droplet size distribution, rheology and physical stability of nanoemulgels containing inulin and omega-3 fatty acids

Background: New consumer habits are forcing the food industry to develop new and healthy products. In response to this tendency, in this investigation, we obtained nanoemulgels by microfluidization containing inulin fibre and omega-3 fatty acids. First, the influence of the number of microfluidization cycles on the physical properties of the nanoemulsions was studied. Subsequently, an advanced-performance xanthan gum was added to the nanoemulsion in different nanoemulsion/xanthan ratios (1:1, 2:1, 3:1, 4:1, 1:2, and 1:3). Results: Laser diffraction, multiple light scattering, and rheology techniques were used to characterize nanoemulsions and the corresponding nanoemulgels. The nanoemulsion with the lowest Sauter mean diameter (138 nm) and the longest physical stability was obtained after three passes through a microfluidization device at a fixed pressure of 103 421 kPa. Thus, these processing conditions were always used to obtain the nanoemulsion; these were subsequently mixed with a xanthan gum solution to produce nanoemulgels that showed weak gel-like viscoelastic and shear-thinning flow behaviours. A decrease in the nanoemulsion/xanthan ratio (i.e. by an increase in the content of xanthan gum in the nanoemulgel) increased the viscoelastic moduli and the zero shear viscosity values. A rise in the droplet size was observed with aging time, probably due to flocculation. The nanoemulsion/xanthan gum mass ratio of 1:3 yielded the most stable nanoemulgel. Conclusions: This work is a contribution to the development of functional foods. It has been demonstrated that it is possible to obtain a stable nanoemulgel-based food matrix containing fibre and omega-3 fatty acids. © 2022 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.Universidad de Sevilla PP2019-1329

Processing variables with high pressure homogenizer as Microfluidizer® influencing on droplet size distribution and physical stability of thyme essential oil/W emulsions

The aim of this work consisted of investigating the influence of the pressure applied with high pressure homogenizer with Microfluidizer® technology (2500, 5000, 7500, 10000, 12500 y 15000 psi) on the droplet size distribution and physical stability of O/W emulsions formulated with thyme essential oil and an alkyl poly pentoside as an emulsifier. In addition, the number of passes (1 or 2 cycles) through the homogenizer is also studied. In order to study the quality of emulsions, techniques such as laser diffraction and multiple light scattering have been used together. It has been shown that, in general, for thyme essential oil emulsions stored at 4ºC, the lower the pressure applied and the number of passes through the homogenizer the better the physical stability being the main mechanisms of destabilization the creaming and the so-called oiling off. This work contributes to the development of ecological emulsions with the added value of that they have antimicrobial properties which is very interesting in industries such as food, cosmetics or agrochemicalEl objetivo de este trabajo ha consistido en investigar cómo influye la presión aplicada en homogeneizador de alta presión con tecnología Microfluidizer® (2500, 5000, 7500, 10000, 12500 y 15000 psi) sobre la distribución de tamaños de gota y estabilidad física de una emulsión O/W formulada con aceite esencial de tomillo y un alquil polipentósido como emulsionante. Adicionalmente se estudia la influencia del número de pasadas (1 y 2) a través del homogeneizador. Para estudiar la calidad de las emulsiones se han utilizado conjuntamente técnicas como la difracción láser y el multiple light scattering. Se ha demostrado que, en general, para las emulsiones de aceite esencial de tomillo almacenadas en frío, a una temperatura de 4ºC, cuanto menor es la presión aplicada y el número de pasadas a través del homogeneizador mejor es la estabilidad física de las mismas siendo los principales mecanismos de desestabilización el cremado y el conocido como oiling off. Este trabajo contribuye al desarrollo de emulsiones ecológicas que tienen además el valor añadido de poseer propiedades antimicrobianas, propiedades de gran interés en industrias como la alimentaria, la cosmética o la agroquímica.Spanish Ministerio de Economía y Competitividad-CTQ2015-70700European Commission (FEDER Programme

Processing and formulation optimization of mandarin essential oil-loaded emulsions developed by microfluidization

Emulsions can be used as delivery systems for bioactive ingredients for their incorporation in food products. Essential oils are natural compounds found in plants that present antioxidant and antimicrobial activity. Therefore, the main goal of this work was to develop emulsions, containing mandarin essential oil stabilized by two food-grade surfactants and guar gum, and to evaluate their physical stability. The initial droplet size of emulsions developed by microfluidization was optimized, obtaining diameters below one micron regardless of the processing conditions. However, the emulsion processed at 25,000 psi and one pass exhibited the lowest mean droplet sizes and polidispersity, and therefore, a higher stability. Different ratios of Tween 80 and Span 80 were assessed as stabilizers. Results obtained indicated that the ratio of surfactants had a significant effect on the mean droplet sizes, physical stability, and rheological properties. Thus, we found that the optimum ratio of surfactants was 75/25 (Tween80/Span80) on account of the lowest droplet mean diameters, lack of coalescence, and a low creaming rate. The rheological characterization of the stable emulsions showed a shear thinning flow behavior, and G" (loss modulus) values higher than G0 (storage modulus) values, in all the frequency range. The rheological behavior may be governed by the guar gum, which was confirmed by field emission scanning electron microscopy (FESEM). This research can be considered as the starting point for future applications of mandarin essential oil in emulsions, which can be incorporated in products as food preservatives.Ministerio de Economía y Competitividad CTQ2015-70700-

Influencia del tensioactiu en la formació i estabilitat física d’emulsions ecològiques concentrades

El objetivo de esta investigación fue comparar tres tensoactivos ecológicos derivados del aceite de coco para la preparación de emulsiones aceite-en-agua concentradas formuladas con α-pineno. Los tensoactivos utilizados son ésteres polietoxilados de glicerina que presentan diferente número de grupos de óxido de etileno, que son responsables principales del carácter hidrófilo del tensoactivo. Las técnicas utilizadas para caracterizar las emulsiones fueron la reología, la difracción láser y el “multiple light scattering”. Se ha demostrado que el uso del tensoactivo no-iónico Levenol C-201 (17 grupos de óxido de etileno y valor HLB de 13), produce emulsiones con mayor estabilidad física debido a sus menores tamaños de gota y una mayor viscosidad, lo que ayuda a prevenir fenómenos de desestabilización como el cremado o la coalescencia. Por tanto, este estudio proporciona importantes resultados sobre las propiedades y estabilidad física de emulsiones formuladas con ésteres etoxilados de glicerina derivados del aceite de coco que pueden ser utilizadas para el desarrollo de nuevos productos bioaplicables.The goal of this work was to compare three different ecological surfactants derived from coconut oil for the preparation of concentrated oil-in-water emulsions formulated with alpha-pinene. The surfactants used were polyoxyethylene glycerol fatty acid esters with different number of oxyethylene groups. These are liable for the hydrophilic surfactant role. Rheology, laser diffraction and Multiple Ligh Sacttering were used in order to characterise the emulsions. It has been demonstrated that the use of Levenol C-201 (HLB: 13) lead to prepare emulsions with longer physical stability due to lower droplet size and higher viscosity. These facts help to slow down destabilization processes such as creaming or coalescence. Therefore, this study provides interesting results about the properties and physical stability of emulsions containing polyoxyethylene glycerol fatty acid esters derived from coconut oil, which can be used to develop new products with biological applications.L’objectiu d’aquesta investigació va ser comparar tres tensioactius ecològics derivats de l’oli de coco per a la preparació d’emulsions oli-en-aigua concentrades formulades amb α-pinè. Els tensioactius utilitzats són èsters polietoxilats de glicerina que presenten diferent nombre de grups d’òxid d’etilè, que són responsables principals del caràcter hidròfil del tensioactiu. Les tècniques utilitzades per caracteritzar les emulsions van ser la reologia, la difracció làser i el multiple light scattering. S’ha demostrat que l’ús del tensioactiu no-iònic Levenol C-201 (17 grups d’òxid d’etilè i valor HLB de 13), produeix emulsions amb més estabilitat física a causa de un volum més petit de gota i una major viscositat, el que ajuda a prevenir fenòmens de desestabilització com el cremat o la coalescència. Per tant, aquest estudi proporciona importants resultats sobre les propietats i la estabilitat física d’emulsions formulades amb èsters etoxilats de glicerina derivats de l’oli de coco que poden ser utilitzades per al desenvolupament de nous productes bioaplicables.(Project CTQ2015- 70700) from the Spanish Ministerio de Economía y CompetitividadEuropean Commission (FEDER Programme)KA

Reliability of Y-Balance Test y Wight Bearing Lunge Test for the clinical-functional evolution of plantar fasciitis

[Resumen] Objetivos: Los objetivos de nuestro estudio han sido determinar en pacientes con FP unilateral la fiabilidad intraobservador del instrumento Y- Balance Test (YBT) y la prueba Wight Bearing Lunge Test (WBLT) medida con el inclinómetro de un telefono movil inteligente. Métodos: Estudio transversal y observacional, realizado con 16 pacientes (9 mujeres y 7 hombres). Resultados: Los resultados obtenidos revelan una excelente fiabilidad relativa intraobservador. El YBT mostró un CCI de 0’946; mientras que las medidas con inclinómetro obtuvieron un CCI de 0’992. En el YBT se apreció una asociación de variables estadísticamente significativa en la dirección posteromedial (p=0’004) y en el resultado general (p=0’017), al comparar el miembro inferior afecto y el sano. Los valores de flexión dorsal en carga con flexión de rodilla se encuentran dentro de los valores normales, sin una asimetría significativa del miembro afecto y el sano. Conclusiones: El Y-Balance Test y la prueba Wight Bearing Lunge Test medida con inclinómetro de teléfono movil inteligente son dos pruebas fiables en pacientes con FP.[Abstract] Objectives: The objectives of our study have been to determine in patients with unilateral PF; The intraobserver reliability of the Y-Balance Test (YBT) and the Wight Bearing Lunge Test (WBLT) measured with the inclinometer of a smartphone. Methods: Cross-sectional and observational study, carried out with 16 patients (9 women and 7 men). Results: The results obtained reveal a excelent intra-rater relative reliability. The YBT showed a CCI of 0.946; while the measures with inclinometer obtained a CCI of 0'992. In the YBT there was a statistically significant association of variables in the posteromedial direction (p= 0’004) and in the overall result (p= 0’017), when comparing the affected lower limb and the healthy. The values of dorsiflexion with knee flexion are within normal values, without a significant asymmetry of the affected and healthy limb. Conclusions: Y-Balance Test and the Wight Bearing Lunge Test measured with smart mobile phone inclinometer are two reliable tests in patients with plantar fasciiti