Designing Food Structure Using Microfluidics

Microfluidics is an emerging technology that can be employed as a powerful tool for designing structures in the food industry. Those structures can modify the texture and flavor perception in a food product or can be used as carrying vehicles for a wide range of bioactive compounds. Microfluidic processes occur in strictly laminar flow, which is quite interesting to process control. This results in particles with more homogeneous size and shape, which improve the properties of controlled release of active compounds and their stability. Innumerable complex structures can be designed, with single or multiple shells, one or more cores inside the particles. In addition, self-assembled structures can be formed in microfluidic devices. However, most of the published works have fundamental character. Fundamental studies are important to understand the physical phenomena that occur at the microscale, in order to obtain successful results in the design of microstructures. Especially in the case of food-grade ingredients, more complex variables have to be considered, such as their rheological and mass- and heat-transport properties. In this review, the fundamentals of microfluidics will be presented, such as the main forces and dimensionless numbers that are involved in the microscale processes and droplet formation regimes. In addition, the most common microfluidic devices will be described, covering their geometries and materials. The review will also present results from studies on structure design using microfluidics, including emulsion-based techniques for the production of microparticles and strategies for the production of self-assembled structures.