There was almost a complete release ( × 108 CFU) of microencapsulated bacteria in the ileal contents within 2 h, while there was no significant release of encapsulated bacteria in the gastric contents even after 8 h of incubation. This study led to the development and design of a protein capsulation for reinforced probiotic protection during the stressful conditions of gastric and controlled release at a defined location. | Vietnam Journal of Science and Technology 56 (2) (2018) 208-215 DOI: USE OF WHEY PROTEIN FOR ENCAPSULATION AND CONTROLLED RELEASE OF PROBIOTIC BACTERIA FROM PROTEIN MICROENCAPSULATE IN EX VIVO PORCINE GASTROINTESTINAL CONTENTS Le Nguyen Thi My*, Nguyen Van Hieu Department of Fishery, Ho Chi Minh City University of Food Industry, 140 Le Trong Tan, Ho Chi Minh City, Vietnam * Email: mylethang81@ Received: 26 May 2017; Accepted for publication: 10 March 2018 Abstract. The aim of this study was to evaluate the efficacy of whey protein isolate (WPI) as an encapsulation matrix for improvement of L. fermentum 39-183 viability to low pH and bile and releasing the encapsulated bacteria in ex vivo porcine gastrointestinal (GI) contents. 1g of protein microcapsules (≈ 108 CFU of L. fermentum 39-183 or E. coli GFP+) were incubated in ex vivo porcine GI contents (9 mL) under anaerobic conditions at 37 0C. Results showed that there was higher than 86 % cell survival for encapsulated L. fermentum 39-183 after 3 h incubation in pH , whereas free cell experienced complete viability loss. Encapsulated L. fermentum 39-183 showed only about log reduction for all bile salt levels tested ( ÷ %), while log decrease of free cell after 6 h of incubation. There was almost a complete release ( × 108 CFU) of microencapsulated bacteria in the ileal contents within 2 h, while there was no significant release of encapsulated bacteria in the gastric contents even after 8 h of incubation. This study led to the development and design of a protein capsulation for reinforced probiotic protection during the stressful conditions of gastric and controlled release at a defined location. Keywords: protein capsules, ex vivo porcine gastrointestinal contents, lactobacillus fermentum 39-183, probiotics. Classification numbers: ; . 1. INTRODUCTION Microencapsulation with respect to a food application involves reversible of active .