Production of supramolecular aggregates by microfluidic platforms: application to food industries

This chapter highlights the potential uses of microfluidics for the preparation of SAs and other MNS, including polymeric nano- and microparticles, for food products. Advances in food science and technology have dictated the need for developing more robust and controllable procedures for the production of MNS. Standard procedures rely on bulk mixing and are generally associated with poor batch-to-batch reproducibility and problems in fast screening aimed at optimizing the MNS properties. In this respect, microfluidics offers the ability to produce MNS in a controllable and reproducible manner, offering a possible solution to the aforementioned drawbacks. Unfortunately, when comparing the intense research in the study of MNS for biomedical applications, relatively little has been done for the design and production of MNS for food and agricultural applications. Considering its high potential in food science, the use of microfluidic-based reactors for the production of various MNS as delivery systems should increasingly attract the attention of researchers involved in food science and industrial applications. The fluid environment in the microfluidic domain has been understood to have important implications for MNS production. Notably, unique features make microfluidics an appealing technique for MNS production, including: (1) controllable and efficient mixing, resulting in a homogeneous reaction environment; (2) a great control of the reaction; (3) in situ monitoring of the entire process for the production of MNS; (4) tuning of the final characteristics of produced MNS by controlling the kinetics of the process; and (5) the possibility to integrate postsynthetic procedures and measurements in a single microfluidic device. These features have been leveraged by some research groups for the production of different categories of MNS, including nanoparticles, polymeric microparticles, liposomes, and emulsions. However, despite this activity and the encouraging results obtained so far, the field of microfluidic production of MNS for food applications remains at an early stage. Microfluidic-mediated preparation procedures have the potential to become a standard production tool for the food industry with an unprecedented degree of controllability and homogeneity. It is opinion of these authors that various aspects should be addressed in the near future to advance this technology. One of the most relevant open problems in microfluidics is related to the low production capacity for MNS. This lack is largely due to the microscale dimension of the chip channels and the related restriction to operate the chips at high flow rates, due to the increase in pressure drop across the microchannels with the increasing flow rate of the pumped fluids. Various strategies to solve this limitation could be proposed, such as new microchip designs where either microvortices, jet-impact, or multilamination strategies could be included. It is expected that in the future more researchers will try to address this challenge, because it represents one of the most important issues which hinder the use of microfluidic devices for food industrial applications. For instance, another possible solution to the low productivity of microfluidic approaches could be represented by the implementation of par- allelization strategies, in which the individual functional units are repeated in parallel chips. However, it is difficult to ensure identical operation conditions for each unit, thus sometimes resulting in lower control of the MNS properties. In conclusion, despite the fact that the use of microfluidics for production of MNS for food applications is not yet a mature industrial applicable procedure, research carried out in recent years has demonstrated that microfluidics could represent a great opportunity for the controlled preparation of MNS for food ingredient purposes, offering a great op- portunity to improve the tuning of their properties. Considering the rapid growth of the fields of functional foods, nutraceuticals, and microfluidics, the efforts at increasing the knowledge at their intersection are likely to provide new and exciting perspectives for tailoring the properties of MNS through controlled microfluidic preparation.