Microencapsulation of papain using carboxymethylated flamboyant (Delonix regia) seed gum D. Betancur-Ancona, J. Pacheco-Aguirre, A. Castellanos-Ruelas, L. Chel-Guerrero ⁎ Facultad de Ingeniería Química, Universidad Autónoma de Yucatán. Periférico Norte, Km. 33.5, Tablaje Catastral 13615, Col. Chuburná de Hidalgo Inn, 97203 Mérida, Yucatán, México abstract article info Article history: Received 24 April 2010 Accepted 15 November 2010 Editor Proof Receive Date 20 December 2010 Keywords: Flamboyant seed Carboxymethylated gums Papain Microencapsulation Use of gums for microencapsulation has increased in the nutraceutical industry. Microcapsule behavior and properties differ between gums and description of non-conventional sources is needed to identify their potential applications. Flamboyant tree Delonix regia seed is not currently used as a commercial gum source, but carboxymethylated flamboyant seed gum (CFG) has properties similar to those of carboxymethylated guar gum. The effectiveness of CFG in microencapsulating papain was evaluated with a 2 3 factorial design and 4 central points. The CFG microcapsules were analyzed with differential scanning calorimetry (DSC) to evaluate particle size, morphology, flow capacity and in vitro papain release. The CFG effectively captured papain. Microcapsule morphology was amorphous when using 2% CFG and spherical when using 3% CFG. Concentration had a significant (p b 0.05) effect on microcapsule behavior with the higher concentration providing better protection in a gastric pH. In an intestinal pH, papain release was higher in the lower concentration CFG microcapsules. This model is a potential controlled delivery system for bioactive substances with several possible industrial applications. Industrial Relevance: Flamboyant (Delonix regia) is most commonly used as an ornamental tree, although its seeds are a potential gum source. This gum has no ionic charge, making it possible to chemically modify it by carboxymethylation and broaden its technological functionality. One possible application is as an encapsulating agent for covering active substances, a technique increasingly used in the food industry. This application is particularly important in nutraceuticals as it provides the option of protecting an active agent and controlling its release. For their potential health benefits, consumer interest is burgeoning in functional foods and nutraceuticals. The growing market for these products and updating of legislation regulating their sale will lead to a boom in novel technologies and ingredients for development of new products and their preservation. © 2010 Elsevier Ltd. All rights reserved. 1. Introduction The use of modified polysaccharides with ionic charge to microen- capsulate substances with biological activity (also known as nutraceu- ticals) has become increasingly popular in the nutraceutical food industry. Microencapsulation protects nutraceuticals, keeps them stable in storage at room temperature and ensures release of an appropriate dosage in a gastric or intestinal pH (Andreev, 2004). In the food industry, the modified polysaccharides carboxymethylcellulose, carboxymethy- lated guar gum and carboxymethylated starch are the most frequently used to encapsulate nutraceutical substances. Their structural char- acteristics allow cross-linking action with metallic bivalent cations (Ca +2 , Ba +2 , Cu +2 and Zn +2 ) and capture of the active substance in its interior (Balassa & Brody, 1968). However, metallic trivalent cations (Fe +3 and Al +3 ) provide better capture of the active substance than metallic bivalent cations, and more effective protection in the gastrointestinal tract (Reddy & Tammishetti, 2002). Gum concentration also influences active substance release (Morkhade & Joshi, 2007), and the structure of the encapsulating agent and encapsulated material. In an evaluation of papain capture rate (%) in alginate using the factors sodium alginate concentration (1, 1.5 and 2%, p/v), calcium chloride concentration (0.5, 0.10 and 0.15 M) and hardening time (20, 25 and 30 min), Sankalia, Mashru, Sankalia, and Sutariya (2004) reported optimum values of 1% alginate, 0.5 M CaCl2 and 20 min hardening time. In a study of bhara gum from Terminalia bellerica (roxb) as an encapsulating agent, Bhabani, Udaya, Balakrishna, and Prasant (2008) reported that increasing gum concentration from 2 to 4% lowered capture efficiency from 88.96 to 84.1%. Somasree and Sabyasachi (2009) found that increasing carboxymethyl xanthan gum from 1.5 to 2.5% improves capture efficiency of another encapsulating agent from 86.5 to 90.7%. Flamboyant (Delonix regia) trees are considered an ornamental species, and native gum from its seeds has not been used previously to microencapsulate nutraceutical substances in food and drugs (Morochi, San Martin, & Ordoñez, 1999; Morochi & Shiomi, 1999). Nonetheless, flamboyant seed native gum (FNG) is potentially useful for microen- capsulation because it contains galactomannan-type polysaccharides similar to those of guar gum (Cyamopsis tetragonalobus) and locust bean Innovative Food Science and Emerging Technologies 12 (2011) 67–72 ⁎ Corresponding author. Tel.: + 52 999 9460989. E-mail address: cguerrer@uady.mx (L. Chel-Guerrero). 1466-8564/$ – see front matter © 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.ifset.2010.11.002 Contents lists available at ScienceDirect Innovative Food Science and Emerging Technologies journal homepage: www.elsevier.com/locate/ifset