Microencapsulation of Lactobacillus plantarum spp in an alginate matrix coated with whey proteins

Whey proteins were used as a coating material to improve encapsulation of Lactobacillus plantarum strains in calcium alginate beads. L. plantarum 299v, L plantarum 800 and L plantarum CIP A159 were used in this study. Inactivation experiments were carried out in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF). Cross-sections of freeze-dried beads revealed the random distribution of bacteria throughout the alginate network. From an initial count of 10.04 +/- 0.01 log(10) CFU g(-1) for L plantarum 299v, 10.12 +/- 0.04 for L plantarum CIP A159 and 10.03 +/- 0.01 for L. plantarum 800, bacteria in coated beads and incubated in SGF (37 degrees C, 60 min) showed a better survival for L plantarum 299v, L plantarum CIP A159 and L plantarum 800 (respectively 7.76 +/- 30.12, 6.67 +/- 0.08 and 5.81 +/- 0.25 logic) CFU g(-1)) when compared to uncoated beads (2.19 +/- 0.09, 1.89 +/- 0.09 and 1.65 +/- 0.10 log(10) CFU g(-1)) (p<0.05). Only bacteria in the coated beads survived in the SIF medium (37 degrees C, 180 min) after SGF treatment. This preliminary work showed that whey proteins are a convenient, cheap and efficient material for coating alginate beads loaded with bacteria. (C) 2008 Elsevier B.V. All rights reserved.