ORIGINAL PAPER Quercetin-Loaded Lecithin/Chitosan Nanoparticles for Functional Food Applications Marthyna P. Souza & Antônio F. M. Vaz & Maria T. S. Correia & Miguel A. Cerqueira & António A. Vicente & Maria G. Carneiro-da-Cunha Received: 18 January 2013 / Accepted: 10 July 2013 / Published online: 4 August 2013 # Springer Science+Business Media New York 2013 Abstract This study aimed at the encapsulation of quercetin into lecithin/chitosan nanoparticles using the electrostatic self-assembly technique, followed by evaluation of their functionality (antioxidant activity) and stability at different environmental conditions. These nanoparticles were charac- terized in terms of: average size, morphology, zeta potential, encapsulation efficiency, loading, and spectroscopic character- istics. Quercetin has been successfully encapsulated in lecithin/ chitosan nanoparticles with an efficiency of 96.13±0.44 %. Nanoparticles presented a spherical morphology with an average size of 168.58±20.94 nm and a zeta potential of 56.46±1.94 mV. Stability studies showed that nanoparticles are stable to temperatures ranging between 5 and 70 °C and a pH variation from 3.3 to 5.0. Moreover, encapsulated quercetin showed improved antioxidant properties when compared to free-quercetin. Our results suggest that quercetin-loaded leci- thin/chitosan nanoparticles can be used in the manufacture of functional foods. Keywords Quercetin-loaded nanoparticles . Bioactive compounds encapsulation . Nanostructure self-assembly . Lecithin/chitosan nanoparticles . Antioxidant Introduction Nanotechnology has potential to produce new food ingredi- ents and innovative products, with considerable benefits to human health (Magnuson et al. 2011). This can be achieved through the development of new structures for applications in functional foods (Huang et al. 2010). The consumption of foods providing health benefits as well as basic nutrition is very attractive to the consumer, and significant develop- ments from the food industry have emerged in recent years. Polyphenols typically used as part of the human diet are one of the most numerous and ubiquitous groups of plant metabolites that have a large spectrum of biological activities and may be considered chemopreventive agents in humans (Fang and Bhandari 2010). Quercetin [3,3′,4′, 5,7- pentahydroxyflavone] is one of the most representative com- pounds of the flavonoid family, having been assigned a wide range of health benefits, including antioxidant activity, cancer prevention, protection to DNA damage, anti-inflammatory, and cardio-protective actions (An et al. 2010). However, quer- cetin is a molecule with a low bioavailability due to its low solubility, gastrointestinal instability, and low absorption in the gastrointestinal tract, which limits its biological effects in vivo (Chitkara et al. 2012). A good option to improve bioavailabil- ity of quercetin is nanoencapsulation that can increase the absorption in the gastrointestinal tract and enhance the mole- cule’ s stability against possible adverse conditions during pro- cessing, distribution, storage, and consumption of food prod- ucts. Promising results, reported by Li et al. (2009), showed that when encapsulating quercetin in solid lipid nanoparticles, consisting of soy lecithin and glyceryl monostearate, the oral bioavailability in rats has doubled. An additional benefit is the M. P. Souza : M. T. S. Correia : M. G. Carneiro-da-Cunha Biochemistry Department, Universidade Federal de Pernambuco—UFPE, Av. Prof. Moraes Rego s/n, CEP 50.670-420 Recife, PE, Brazil M. P. Souza : M. A. Cerqueira : A. A. Vicente IBB—Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, Universidade do Minho, Campus de Gualtar, 4710-057 Braga, Portugal A. F. M. Vaz Unidade Acadêmica de Medicina Veterinária, Universidade Federal de Campina Grande, CEP 58.7000-970 Patos, PB, Brazil M. G. Carneiro-da-Cunha (*) Laboratório de Imunopatologia Keizo Asami-LIKA/UFPE, Campus Universitário, s/n, CEP 50670-901 Recife, PE, Brazil e-mail: mgcc@ufpe.br Food Bioprocess Technol (2014) 7:1149–1159 DOI 10.1007/s11947-013-1160-2