Journal of Food Research; Vol. 6, No. 3; 2017 ISSN 1927-0887 E-ISSN 1927-0895 Published by Canadian Center of Science and Education 40 Encapsulation of Anthocyanins from Black Rice (Oryza Sativa L.) Bran Extract using Chitosan-Alginate Nanoparticles Rodel M. Bulatao 1 , John Paulo A. Samin 1 , Joel R. Salazar 2 & Juvy J. Monserate 2 1 Rice Chemistry and Food Science Division, Philippine Rice Research Institute, Maligaya, Science City of Muñoz, Nueva Ecija 3119, Philippines 2 Department of Chemistry, College of Arts and Sciences, Central Luzon State University, Science City of Muñoz, Nueva Ecija 3119, Philippines Correspondence: Rodel M. Bulatao, Rice Chemistry and Food Science Division, Philippine Rice Research Institute, Maligaya, Science City of Muñoz, Nueva Ecija 3119, Philippines. E-mail: rudy_macky@yahoo.com and rm.bulatao@philrice.gov.ph Received: October 20, 2016 Accepted: February 3, 2017 Online Published: April 11, 2017 doi:10.5539/jfr.v6n3p40 URL: https://doi.org/10.5539/jfr.v6n3p40 Abstract This study was conducted to extract and encapsulate anthocyanins from black rice bran using chitosan-alginate nanoparticles. Ten black rice varieties were screened for the anthocyanin content and the variety with the highest anthocyanins was used for the encapsulation. The anthocyanins were extracted by defatting the bran with n-hexane and soaking it with 85% acidified ethanol. The crude anthocyanin extract (CAE) was freeze-dried at -110°C for 48 h and then encapsulated in chitosan-alginate nanoparticles using two processes: ionic pre-gelation and polyelectrolyte complex formation. The mass ratio of chitosan and alginate polymers used in this study was 100:10. The treatments applied were as follows: T 0 -0 mg CAE, T 1 -10 mg CAE, T 2 -20 mg CAE, and T 3 -30 mg CAE. The resulting capsules were characterized in terms of chemical properties, surface morphology, particle size, polydispersive index, encapsulation efficiency, and 2, 2-diphenyl-1-picrylhydrazyl radical scavenging activity. Screening of rice samples indicated that Ominio bran had the highest anthocyanin content (36.11 mg/g). Anthocyanins were successfully encapsulated in the matrix as shown by the Scanning Electron Microscopy images and Fourier Transform Infrared spectra of the anthocyanin-loaded chitosan-alginate nanoparticles. Among the different concentrations of CAE, T 3 had the highest encapsulation efficiency (68.9%) and antioxidant scavenging activity (38.3%) while T 1 and T 2 had the lowest. Ascending particle size was observed for T 0 (358.5 nm), T 3 (467.9 nm), T 1 (572.3 nm), and T 2 (635.9 nm). All anthocyanin-loaded capsules were found to be of nano-size (<1000 nm). The study concluded that chitosan-alginate nanoparticles can be a good encapsulating material for anthocyanin. Keywords: antioxidant, anthocyanins, black rice bran, chitosan-alginate nanoparticles, encapsulation, nanocapsule 1. Introduction The Philippines being one of the top rice producers in the world produced about 18.15 million metric tons of paddy rice in 2015 (Philippine Statistics Authority, 2016). This huge amount of paddy rice contributed significantly in the generation of agricultural by-products such as rice bran. The bran is mainly used in the country as feed supplement for livestock production; however, several studies have been reported that it is a good source of protein, vitamins, micronutrients, and antioxidants (Moongngarm et al., 2012). The major antioxidants found in the bran particularly in pigmented rice are the anthocyanins. Anthocyanins are one of the most abundant groups of flavonoids in nature and are responsible for the bright and colorful pigmentation of fruits, vegetables, and some cereal grains (Shipp & Abdel-Aal, 2010). Anthocyanins are known to exhibit antimicrobial, anticancer, and anti-hyperglycemic properties (Andersen & Jordheim, 2006). These compounds are very promising particularly as ingredient for functional and pharmaceutical products, but they have limited use due to their low stability under varying environmental conditions (pH, light, oxygen, and heat) and high reactivity with other compounds in the food matrix (Cavalcanti et al., 2011; Robert & Fredes, 2015).