Unravelling nanoemulsions vs excipient nanoemulsions: formulation optimization, particle characterization and behavior as α-tocopherol delivery systems

Abstract

The consumption of functional foods incorporating bioactive compounds as a way to promote a healthier lifestyle has gained particular interest in research community and food industry. Firstly, 3D printing has been used in food manufacturing as a novel technology in this field to improve food sensorial properties (e.g., appearance and texture) as well as nutritional/functional content. Secondly, since bioactive compounds bioavailability can be compromised during post-processing, storage, and digestion, their association with nanostructures may enhance their bioavailability and consequently be used for food fortification. In this sense, a novel functional food concept is being developed by printing perishable healthy food products (i.e., vegetables and fruits) previously fortified with nanostructures incorporating bioactive compounds. Whey protein isolate (WPI) nanostructures were developed to associate riboflavin (Rb), and their storage stability, safety and Rb bioaccessibility were evaluated. Storage stability was evaluated by assessing nanostructures size and polydispersity (PdI) over 45 days at 4 °C and 25 °C. Rb bioaccessibility was determined by quantifying Rb concentration in soluble fraction after digestion, that was performed using INFOGEST static in vitro gastrointestinal model. Nanostructures effect on cell viability was assessed by performing a MTT assay using Caco 2 cell line. Rb-loaded WPI nanostructures showed no statistically significant differences in terms of size (ca. 120 nm) and PdI (0.2) during storage period, at both temperatures tested. Rb bioaccessibility was enhanced in ca. 11 % when associated in WPI nanostructures, and Caco 2 cell viability was not affected up to 0 1 mg/mL-1 of Rb in WPI nanostructures. Finally, some pre-tests results regarding the 3D printing of a carrot paste are given, where its shape and rheological profile were evaluated. These results may contribute to validate the use of WPI nanostructures as effective encapsulating systems allied with 3D-food printing towards the development of functional foods with personalized structure and nutrition.