Davalos Saucedo, Cristian Aaron (2014) Microencapsulation for tailored food using microfluidics in industrial processes. [Tesi di dottorato]

Preview

Text Tesi Davalos Saucedo Cristian Aaron_XXVI_Ciclo.pdf Download (4MB) | Preview

Collection description

Microfluidics technologies are of great interest on research due to their advantages and the possibility to use it on different industrial areas. For food industry could be an important innovation for the microencapsulation of aromas to improve flavors or mask disgusting flavors improving the palatability of the product or giving an added value to the product. The aim of this work was to develop a microfluidic device to encapsulate essential oil through a flow-focusing technique using mainly sodium alginate as matrix. Different devices were created to test and to compare the possibility of produce microparticles and the important parameters for the production of microparticles production using flow focusing. Due to the versatility of the devices, the diameter size of the droplets generated in different emulsion configuration such as (o-w) (w-o), is possible to reach a size of the droplets generated from 200µm (CV > 9%). A monodispersed droplets generation of proteins and pectin (P/P) using sunflower oil for their formation using an opposing focusing flows in a coaxial capillaries device and varying the flow ratio between P/P inner flow rate and oil and consequently controlling with precision the droplet diameter. Obtained droplets have dimensions from 200 µm diameter, showed good stability over time and good properties to be used as a material for active films production. Moreover, the microfluidic device was modified using 3 capillaries, by the central capillary was injected a first fluid as a core of the droplet (active principle) then, a second fluid recovers the (oily) core part of the disperse phase, a third fluid (sunflower oil) continuum phase is useful to focus the disperse phase generating the droplets. For the microparticles production using sodium alginate, different geometries configurations were tested, trying to keep the simplest design that allows the scaling up easily for the industrial application. However changing the configuration allows to produce forms of microparticles of diverse kinds such as matrix, mononuclear, or multinuclear for instance. Although for practical uses the most of the tests were conducted in a configuration of the geometry to produce microparticles in a matrix form due to its simplicity. Also there are proposed different uses that can be applied easily, using the same technique and the same devices with a minimum of modifications that can be used in the food industry. Some examples are the mixing of solutions with accurate precision, cell encapsulation and the production of complexes of protein pectin. Another modification of the device was the use of air to improve the microparticle production. In this case, the alginate solidification of microparticles was performed using gellification with direct immersion on calcium chloride at relative high speed. Finally, an industrial application into a baked-frozen bread was made to conserve the aroma and/or to mask disgusting aromas, preparing an emulsion with alginate, rosemary essential oil and surfactants such as Tween 20 and Span 80. The microparticles were prepared previously and solidified then were added to the bread and packed. Samples were analyzed using a gas chromatograph. The results did not shown any difference between the samples with alginate microparticles containing rosemary essential oil and the control samples prepared in the absence of microparticles. In conclusion, it is of great importance to know the different characteristics involved in this technique such as materials used, solution polarity, configuration of the geometry, emulsionant presence, but the most important consideration for the well functionality of the devices is the concentricity due to the nature axisymmetric of the system.

Downloads

Actions (login required)

View Item