Preparation of solid lipid nanoparticles containing active compound by electrohydrodynamic spraying Megdi Eltayeb a , Poonam Kaushik Bakhshi a , Eleanor Stride b , Mohan Edirisinghe a, ⁎ a Department of Mechanical Engineering, University College London, Torrington Place, London, WC1E 7JE, UK b Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Old Road Campus Research Building, Headington, OX3 7DQ, UK abstract article info Article history: Received 26 January 2013 Accepted 30 March 2013 Keywords: Electrohydrodynamic Lipid Nanoparticles Maltol Electrohydrodynamic (EHD) processing and forming has been successfully used to encapsulate a range of ac- tive ingredients but its application in flavour enhancement has been very limited. In this study, an EHD meth- od is used for the first time to prepare nanosized particles of solid lipids, i.e. stearic acid and ethylcellulose encapsulating maltol flavour. The weight ratio of stearic acid: ethylcellulose was kept at 5. Particles, which were spherical in shape and 10–100 nm in diameter, were obtained with stable jetting with the applied volt- age set to 13–15 kV and using flow rates of 10 and 15 μl/min. The maltol encapsulation efficiency and yield were 69.5% and 69%, respectively. Fourier transform infrared spectroscopy confirmed the presence of maltol within the stearic acid–ethylcellulose matrix, without any chemical interaction between ingredients. © 2013 Elsevier Ltd. All rights reserved. 1. Introduction Nanotechnology is the understanding and control of matter at di- mensions of ~1–100 nm. There is a huge demand for nanotechnology in the food industry (Fathi & Mohebbi, 2010; Neethirajan & Jayas, 2011; Rizvi, Moraru, Bouwmeester, & Kampers, 2010). However, many nanotechnological applications in the food sector may be difficult to adopt commercially, owing to high cost and/or scale requirements. Nanotechnology has been used to deliver bioactive ingredients (Chen, Weiss, & Shahidi, 2006; Shimoni, Edited, & Gustavo, 2009) and nanoencapsulation has been exploited in pharmaceutics, cosmetics and food science (Farokhzad & Langer, 2009; Müller, Petersen, Hommoss, & Pardeike, 2007; Risch & Reineccius, 1995; Sagalowicz, Leser, Watzke, & Michel, 2006; Shah et al., 2007; Shimoni, Edited, & Gustavo, 2009) with a variety of polymeric matrices being used, such as sodium alginate, pectin, chitosan and lipids based materials (Chang et al., 2005). Also the properties of bioactive compounds can be improved by encapsulating them, such as their prolonged residence time in the gastrointestinal tract, delivery, solubility, and the efficient absorption through cells (Chen, Remondetto, & Subirade, 2006). The successful utilisation of nanoparticles in various industries, particularly in biotechnology, is dependent largely on their uptake by body tissue (i.e. via cell membrane), controlled and sustained re- lease of active ingredient through polymeric matrices and their stabil- ity. Solid lipid nanoparticles (SLN) are a colloidal carrier system for bioactive compounds. SLN are generally made of a lipid-based matrix (Müller, Mäder, & Gohla, 2000). Recently SLN have been gaining impetus scientifically and commer- cially in the pharmaceutical as well as the food industries (Awad et al., 2008; Gallarate, Trotta, Battaglia, & Chirio, 2009; Varshosaz, Tabbakhian, & Mohammadi, 2009; Varshosaz et al., 2010). SLN have been developed as an alternative to conventional carrier systems such as emulsions, lipo- some, etc. Owing to their unique properties such as high encapsulation efficiency, small size, increased surface area, SLNs have great potential in applications requiring controlled release, variability in active ingredi- ent content and stabilisation, biodegradability and biocompatibility (Cavalli, Caputo, & Gasco, 1993). They are also commercially viable and have gained regulatory approval (Müller, Mäder, & Gohla, 2000; Smith & Hunneyball, 1986). Further, for food applications, the polymeric material which can be designed to encapsulate active ingredient must be edible, biodegradable and able to form a barrier between the internal phase and its surroundings (creating a modified atmosphere restricting the transfer of gases (O 2 , CO 2 )) and also becoming a barrier for transfer of aromatic flavour compounds (Miller & Krochta, 1997). The fatty acid nature of the saturated 14, 16 and 18-carbon chain (i.e. stearic acid (SA), butterfat, and palmitic acid) at normal human body temperature is commonly used in selecting the lipid matrix to prepare SLN (Bocca et al., 1998; Cavalli et al., 1997; Gasco, Cavalli, & Carlotti, 1992; Mehnert & Mader, 2001; Zhang, Yie, Li, Yang, & Nagai, 2000). These form the bulk of fatty acid in animal body tissue (Bruss, 1997). SLN prepared using SA, therefore, are approved by reg- ulatory authorities and hence their application for the delivery of ac- tive ingredient is acceptable. Furthermore, SA is known to have a neutral effect on the plasma lipid profile as it is rapidly converted to oleic acid within the body (Bonanome, Bennett, & Grundy, 1992) and it does not increase plasma cholesterol concentration like other saturated fatty acids (Hegsted, McGandy, Myers, & Stare, 1965). Food Research International 53 (2013) 88–95 ⁎ Corresponding author. Tel.: +44 20 76793942; fax: +44 2073880180. E-mail address: m.edirisinghe@ucl.ac.uk (M. Edirisinghe). 0963-9969/$ – see front matter © 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.foodres.2013.03.047 Contents lists available at SciVerse ScienceDirect Food Research International journal homepage: www.elsevier.com/locate/foodres