Original article Liposomes encapsulating beta-carotene produced by the proliposomes method: characterisation and shelf life of powders and phospholipid vesicles Marı´lia Moraes, Jose ´ Ma ´rio P. Carvalho, Cı´ntia R. Silva, Stefany Cho, Mirella R. Sola & Samantha C. Pinho* Department of Food Engineering, Faculty of Animal Science and Food Engineering, University of Sa˜o Paulo (USP), Av. Duque de Caxias Norte 225 – Jd Elite, Pirassununga, SP, 13635-900, Brazil (Received 27 February 2012; Accepted in revised form 17 July 2012) Summary The objective of this study was to investigate the feasibility of producing proliposomes incorporating beta-carotene by spray drying and to assess the capacity of the liposomes produced by the hydration of the dry phospholipid particles to preserve the encapsulated carotenoid. Powders containing beta-carotene, hydrogenated phosphatidylcholine and sucrose were obtained and characterised in terms of crystallinity, morphology, thermal behaviour, density, solubility and hygroscopicity. The preservation of beta-carotene in the powder was evaluated for two storage conditions under normal atmosphere and vacuum. The pro- liposome was highly soluble, with all components embedded in the matrix and capable of preserving more than 90% of the incorporated beta-carotene for 60 days of refrigerated storage under vacuum. The lipo- some dispersions maintained their average size, polydispersity index and zeta potential for 100 days of storage. After 60 days, the degradation of encapsulated beta-carotene was minimal, and the colour of the dispersions was preserved. Keywords Beta-carotene, liposomes, microencapsulation, proliposomes, spray drying. Introduction Liposomes, or phospholipid vesicles, are versatile carriers for both hydrophilic and hydrophobic bioactive molecules, with advantages including being natural, biodegradable and non-toxic (Kosajaru et al., 2006). Food applications of these colloidal structures greatly increased in the last decade, and many examples of encapsulated substances in food formulations can be found in the literature, such as ferrous sulphate (Xia & Xu, 2005; Kosajaru et al., 2006), enzymes (Benech et al., 2003; Xia et al., 2006; Nongonierma et al., 2009), antimicrobial agents (Were et al., 2003, 2004; Teixeira et al., 2008; Mal- heiros et al., 2010), ferrous glycinate (Ding et al., 2009, 2011), vitamins (Maranasco et al., 2011), func- tional peptides (Morais et al., 2003; Hwang et al., 2010; Yokota et al., 2012), salidroside (Fan et al., 2007), essential oils (Gortzi et al., 2007, 2008; van Vuuren et al., 2010; Yoshida et al., 2010) and carot- enoids (Xia et al., 2011). An important issue with the production of these dispersions, however, is the scale-up. The establishment of appropriate methods to produce large quantities of liposomes in a con- trolled and reproducible way is a challenge (Wagner & Vorauer-Uhl, 2011), but one of the processes suit- able for scaling-up liposome production is the use of proliposomes. Proliposomes can be defined as aque- ous-soluble dry phospholipid particles with loading ingredients and whose hydration above transition temperature and appropriate agitation conditions will result in the formation of liposomes (Payne et al., 1986; Elhissi et al., 2006; Xia et al., 2011). Controlled and reproducible liposome preparation is possible using a chosen dilution rate and tempera- ture (Wagner & Vorauer-Uhl, 2011). Dry phospho- lipid particles can be produced by several methods, such as freeze drying, power bed grinding, the crys- tal-film method, modified thin-film deposition, super- critical techniques and spray drying (Kikuchi et al., 1991; Alves & Santana, 2004; Xia et al., 2011). The use of spray drying is of special interest in liposome production for food. As it is extremely well known in food processes, several studies about spray drying are found in the literature, and its scale-up is exten- sively studied. Beta-carotene is a natural pigment of the isoprenoid class, whose key structural element is the conjugated polyene backbone (Kohler, 1995). When ingested at *Correspondent: Fax: +55 19 3565 4284; e-mail: samantha@usp.br International Journal of Food Science and Technology 2013, 48, 274–282 doi:10.1111/j.1365-2621.2012.03184.x © 2012 The Authors. International Journal of Food Science and Technology © 2012 Institute of Food Science and Technology 274