Development and characterization of solid lipid microparticles loaded with ascorbic acid and produced by spray congealing Fernando Eustáquio Matos-Jr a, ⁎, Marcello Di Sabatino b , Nadia Passerini b , Carmen Sílvia Favaro-Trindade a , Beatrice Albertini b a University of São Paulo, College of Animal Science and Food Engineering, Av. Duque de Caxias Norte, 225, CP 23, CEP 13535 900 Pirassununga, São Paulo, Brazil b University of Bologna, Department of Pharmacy and Biotechnology, Via San Donato 19/2, 40127 Bologna, Italy abstract article info Article history: Received 19 August 2014 Accepted 4 November 2014 Available online 10 November 2014 Keywords: Vitamin C Stability Encapsulation efficiency Spray chilling Spray cooling The aim of this work was to produce solid lipid microparticles loaded with ascorbic acid (AA). The microparticles were produced using spray congealing technique with a theoretical AA loading of 15, 25 or 40% (w/w). Fully hydrogenated palm oil and vegetable glycerol monostearate were used as carriers. The microparticles were characterized in terms of yield, morphology (SEM), mean size, size distribution, thermal behavior (DSC), encapsulation efficiency and stability of AA. The microparticles were spherical, the process yield was over 81% and the encapsulation efficiency ranged from 74 to 84%. The stability of the encapsulated AA was over 75% after 56 days of storage. The type of carrier, the AA concentration and the storage temperature did not significantly influence the stability. In conclusion microencapsulation by spray congealing is an important alternative to ensure AA stability, even at temperatures higher than those commonly used in food storage. © 2014 Elsevier Ltd. All rights reserved. 1. Introduction Ascorbic acid (AA) has been widely used in the food industry in two different functions: as an antioxidant compound and as a source of vitamin C in the diet. As an antioxidant, AA inhibits lipid auto-oxidation and enzymatic browning. The mechanisms of action involved in its antioxidant activity include the deactivation of singlet oxygen, the re- duction of oxygen radicals and central carbons with the production of a less reactive semi-dehydroascorbate radical or L-dehydroascorbic acid, the preferential oxidation of ascorbate together with oxygen depletion, and the regeneration of other antioxidants by means of the reduction of tocopherol radicals, for example (Fennema, Damodaran, & Parkin, 2010). Despite its efficacy in the preservation of the natural color and taste/ flavor of foods, AA suffers from high instability. Environmental factors, such as high temperature, high pH, and the presence of oxygen, metallic ions, UV and X-rays may affect its stability, diminishing its vitamin activities and reducing its power during the processing and storage of foods. In addition, due to its high reactivity, when AA is added to foods it can react with other ingredients and cause undesirable changes in the color and taste of the food product (Uddin, Hawlader, & Zhu, 2001). A promising strategy to improve AA stability is the use of microencap- sulation. This process was defined by Arshady (1993) as the process of packing a solid, liquid or gas material in extremely small capsules that re- lease the contents in a controlled manner and under specific conditions. Encapsulation has become extremely popular in the food industry due to interest in adding to food matrices bioactive ingredients that cannot be added in their free forms because they are sensitive to envi- ronmental factors, such as the presence of light, oxygen, and extremes of pH (Abbas, Weia, Hayatb, & Xiaominga, 2012). AA encapsulation not only may reduce AA degradation during processing and storage but also may prevent it from interacting with other components of the food matrix, which can cause a decrease in the quality of the product. Besides, encapsulation also can mask the acid taste promoted by AA in the food. Several microencapsulation techniques have been approached to improve the stability of ascorbic acid, such as spray drying (Trindade & Grosso, 2000; Uddin et al., 2001; Esposito, Cervellati, Menegatti, Nastruzzi, & Cortesi, 2002; Desai, Liu, & Park, 2005; Righetto & Netto, 2006; Pereira et al., 2009), double emulsion followed by complex coacer- vation (Comunian et al., 2013), liposome preparation (Kirby, Whittle, Rigby, Coxon, & Law, 1991; Kim & Baianu, 1991; Sharma & Lal, 2005; Wechtersbach, Polak, Ulrih, & Cigić, 2011), fluidized bed coating (Knezevic, Gosak, Hraste, & Jalsenjako, 1998), melt extrusion (Chang et al., 2010; Leusner, Lakkis, Van Lengerich, & Jarl, 2002), melt dispersion (Uddin et al., 2001), microfluidic technology (Comunian, Abbaspourrad, Favaro-Trindade, & Weitz, 2014) and solvent evaporation (Uddin et al., 2001). Food Research International 67 (2015) 52–59 ⁎ Corresponding author. Tel.: +55 19 3565 4139; fax: +55 19 3561 8606. E-mail address: fernandoeustaquio@hotmail.com (F.E. Matos-Jr). http://dx.doi.org/10.1016/j.foodres.2014.11.002 0963-9969/© 2014 Elsevier Ltd. All rights reserved. Contents lists available at ScienceDirect Food Research International journal homepage: www.elsevier.com/locate/foodres