Contents lists available at ScienceDirect Food Chemistry journal homepage: www.elsevier.com/locate/foodchem Short communication Electrosprayed whey protein-based nanocapsules for β-carotene encapsulation Rui M. Rodrigues a , Philippe E. Ramos a , M.F. Cerqueira b,c , José A. Teixeira a , António A. Vicente a , Lorenzo M. Pastrana b , Ricardo N. Pereira a , Miguel A. Cerqueira b, ⁎ a CEB – Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal b INL – International Iberian Nanotechnology Laboratory, Av. Mestre José Veiga s/n, 4715-330 Braga, Portugal c Centre of Physics, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal ARTICLE INFO Keywords: Nanotechnology Encapsulation Electrohydrodynamic process Functional compounds ABSTRACT In this work an electrohydrodynamic process (electrospray) was used to produce β-carotene loaded nanocapsules based on whey protein isolate (WPI). WPI solutions were prepared in aqueous solutions with different con- centrations of ethanol (5, 10 and 15%) which were used for β-carotene solubilization. Different electrospray conditions were tested and the morphology and molecular organization of the nanocapsules were studied on dried and hydrated state. The size of the dried nanocapsules ranged between 227 and 283 nm. After hydration, there was a significant increase in the mean size of the nanocapsules, being the sizes higher for nanocapsules produced with increasing concentrations of ethanol. Results, obtained from the reactivity of free sulfhydryl groups and fluorescence analysis, showed that the increase of ethanol concentration had a destabilizing effect on the protein unfolding. Electrosprayed WPI-based nanocapsules can be used for the encapsulation of β-carotene answering the in- dustrial demand for novel encapsulation technologies to protect sensitive bioactive compounds. 1. Introduction Nanoencapsulation offers many benefits for the development of delivery systems with enhanced properties. Delivery systems at na- noscale present better physicochemical properties – i.e. optical, thermal, absorption and stability – when compared with micro- and macroscale systems, which make their use very attractive in the pro- cessing of functional foods and novel packing systems. The main aspect that oversees this behaviour is the area-to-volume ratio once it de- termines the physicochemical characteristics and brings several ad- vantages, such as a high encapsulation efficiency and stability, a tai- lored control release, an enhanced solubility and also the prevention of undesirable chemical reactions (Cerqueira et al., 2014; Cerqueira et al., 2017). Electrohydrodynamic process (electrospinning and electrospray) present an interesting solution for encapsulation of bioactive molecules. This methodology is able to create capsules and fibers with different sizes (at nano- and microscale) with a large surface to volume ratio, as well as to encapsulate, coat and dry the compounds in a one-step pro- cess (Anu Bhushani & Anandharamakrishnan, 2014; Martín, Lara- Villosslada, Ruiz, & Morales, 2015). In this production process, temperature is not required, allowing the preservation of thermally labile compounds. This is possible due to an electrically-driven force used during the electrohydrodynamic processing, which leads to the formation of an electrically charged fluid cone jet (Taylor cone) of the biopolymer solution between the spinneret and the collector. This cone is obtained when the equilibrium of the electric forces and surface tension is destroyed. The use electrohydrodynamic processes for the encapsulation of bioactive compounds have been punctually addressed. Aceituno- Medina, Mendoza, Lagaron, and López-Rubio (2014) tested the en- capsulation of folic acid in amaranth protein isolate (API) and pullulan electrospun fibers, reporting an increase of the thermal stability of the structure and showing that is possible to avoid folic acid degradation, assessed by the photoprotection during 120 min. Using whey protein concentrate (WPC), López-Rubio and Lagaron (2012) showed the pos- sibility of using the electrospray process to encapsulate β-carotene in nanoparticles, with a high encapsulation efficiency and, at the same time, allows the stabilization of β-carotene against photo-oxidation. Both lipophilic and hydrophilic bioactive compounds can be en- capsulated by electrospray, but when using proteins the solubility of the lipophilic compounds can be challenging. The use of organic solvents https://doi.org/10.1016/j.foodchem.2019.126157 Received 22 February 2019; Received in revised form 18 November 2019; Accepted 31 December 2019 ⁎ Corresponding author. E-mail address: miguel.cerqueira@inl.int (M.A. Cerqueira). Food Chemistry 314 (2020) 126157 Available online 07 January 2020 0308-8146/ © 2020 Elsevier Ltd. All rights reserved. T