LWT 41 (2008) 493–500 Effect of microencapsulation on viability and other characteristics in Lactobacillus acidophilus ATCC 43121 Se-Jin Kim a , Seung Yong Cho b , Sae Hun Kim c , Ok-Ja Song d , II-Shik Shin d , Dong Su Cha a,1,2 , Hyun Jin Park e,f,Ã,2 a Graduate School of Biotechnology, Korea University, Seoul 136-713, South Korea b Institute of Life Sciences and Biotechnology, School of Life Sciences and Biotechnology, Korea University, Seoul 136-713, South Korea c Division of Food Bioscience and Technology, College of Life Sciences and Biotechnology, Korea University, Seoul 136-713, South Korea d Division of Marine Bioscience & Technology, Kangnung National University, Kangnung, South Korea e Graduate School of Biotechnology, Korea University, Seoul 136-701, South Korea f Department of Packaging Science, Clemson University, Clemson, SC 29634-0370, USA Received 2 September 2006; received in revised form 23 March 2007; accepted 29 March 2007 Abstract Lactobacillus acidophilus ATCC 43121 were microencapsulated with sodium alginate by dropping method. The effects of microencapsulation on the changes in survival rate of the L. acidophilus ATCC 43121 during exposure to artificial gastrointestinal and on the change in heat susceptibility of L. acidophilus ATCC 43121 during the heat treatment were studied. In addition, cholesterol assimilation and intestinal adhesion of non-encapsulated and encapsulated L. acidophilus ATCC 43121 were also investigated to explore the effect of microencapsulation on health beneficial effect of lactic acid bacteria. Non-encapsulated cells were completely destroyed when exposed to artificial gastric juice (AGJ) of pH 1.2 and 1.5, while the treatment declined the viable count of encapsulated samples only by 3 log. Encapsulated cells exhibited a significantly higher resistance to artificial intestinal juice (AIJ) and heat treatment than non- encapsulated samples. The assimilative reductions of cholesterol by non-encapsulated and encapsulated L. acidophilus ATCC 43121 were 35.98% and 32.84%, respectively. However, encapsulation did not significantly (P40.05) affect the adherence of L. acidophilus ATCC 43121 onto the human intestinal epithelial cell lines HT-29. The microencapsulation effectively protected the microorganisms from heat and acid treatment in delivering the viable cells to intestine without any significant adverse effect on their functionalities. r 2007 Swiss Society of Food Science and Technology. Published by Elsevier Ltd. All rights reserved. Keywords: Lactobacillus acidophilus; Microencapsulation; Alginate; Gastrointestinal tract; Heat treatment; Cholesterol assimilation; Intestinal adhesion 1. Introduction Probiotics have been defined as ‘‘live microbial feed supplements that have beneficial effects on the host by improving their intestinal microbial balance’’ (Adhikari, Mustapha, Gru¨n, & Fernando, 2000). Probiotic bacteria, lactic acid bacteria (LAB), which are typically associated with the human gastrointestinal tract, have been reported to suppress the growth of pathogens (Coconnier et al., 1993; Kaur, Chopra, & Saini, 2002; Lehto & Salminen, 1997; Lim, Huh, & Baek, 1993; Reid & Burton, 2002) and stabilize the digestive system by increasing intestinal barrier functions (Simon & Gorbach, 1984). Probiotic bacteria ferment food-derived indigestible carbohydrates to pro- duce short-chain fatty acids in the gut, which can then cause a decrease in the systemic levels of blood lipids by inhibiting hepatic cholesterol synthesis (Gilliland, Nelson, & Maxwell, 1985; Gilliland & Walker, 1990; Klaver & Vandermeer, 1993; Noh, Kim, & Gilliland, 1997; Walker & Gilliland, 1993). Other efficacies of probiotic bacteria include prevention of diarrhea and constipation diseases (Cremonini et al., 2001; Gorbach, 2000; Kailasapathy & ARTICLE IN PRESS www.elsevier.com/locate/lwt 0023-6438/$30.00 r 2007 Swiss Society of Food Science and Technology. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.lwt.2007.03.025 Ã Corresponding author. Tel.: +82 2 3290 3450; fax: +82 2 927 9028. E-mail addresses: dallasking@hanmail.net (D.S. Cha), hjpark@korea.ac.kr (H.J. Park). 1 Also to be corresponded to. Tel.: +82 2 3290 4279; fax: +82 2 3291 4149. 2 Both the authors contributed equally to this research.