This work aims at evaluating encapsulation and controlled release of vitamin B2 from alginate/chitosan nanoparticles. Ionotropic polyelectrolyte pre-gelation was used as production method being chitosan and alginate used as main materials. Nanoparticles were characterized in terms of average size, polydispersity index (PDI), zeta potential and vitamin entrapment efficiency. The average size for alginate/chitosan nanoparticles was 119.5±49.9nm for samples without vitamin B2 and 104.0±67.2nm with the encapsulation of vitamin B2, presenting a PDI of 0.454±0.066 and 0.319±0.068, respectively. The nanoparticles showed encapsulation efficiency and loading capacity values of 55.9±5.6% and 2.2±0.6%, respectively. Release profiles were evaluated at different conditions showing that the polymeric relaxation was the most influent phenomenon in vitamin B2 release. In order to study their stability nanoparticles were stored at 4°C being particles sizes and PDI evaluated during 5 months showing the results that vitamin B2-loaded nanoparticles are more stable (in terms of size and PDI) than nanoparticles without vitamin B2.

Nanotechnology has been referred to as one of the most interesting topics in food technology due to the potentialities of its use by food industry. This calls for studying the behavior of nanosystems as carriers of biological and functional compounds aiming at their utilization for delivery, controlled release and protection of such compounds during food processing and oral ingestion. This review highlights the principles of design and production of bio-nanosystems for oral delivery and their behavior within the human gastrointestinal (GI) tract, while providing an insight into the application of reverse engineering approach to the design of those bio-nanosystems. Nanocapsules, nanohydrogels, lipid-based and multilayer nanosystems are discussed (in terms of their main ingredients, production techniques, predominant forces and properties) and some examples of possible food applications are given. Phenomena occurring in in vitro digestion models are presented, mainly using examples related to the utilization of lipid-based nanosystems and their physicochemical behavior throughout the GI tract. Furthermore, it is shown how a reverse engineering approach, through two main steps, can be used to design bio-nanosystems for food applications, and finally a last section is presented to discuss future trends and consumer perception on food nanotechnology.

In this work rhamnolipids were evaluated as surfactants for the production of nanostructured lipid carriers (NLCs). NLCs were produced by melt-emulsification using ultra-homogenisation followed by ultrasonication and different ratios of medium-chain-triglycerides and glycerol monostearate (lipid phase) were tested. NLCs presented sizes and polydispersity index values ranged between 97 and 120 nm and 0.20-0.26, respectively. Transmission electron microscopy observations confirmed the size and the spherical morphology of the NLCs. The thermal analysis and X-ray diffraction showed that the amount of solid lipid (glycerol monostearate) influences the melting, crystallisation and enthalpy of NLCs and their degree of crystallinity. Results showed that NLCs were more stable at 4 • C and the best formulation (1% of water phase, 0.05% of biosurfactant and solid: liquid ratio of 10:90) was stable for 30 days. This work showed the possibility of using rhamnolipids to produce NLCs and represent an important step for the development of lipid-based nanosystems using biosurfactants.