Micro-encapsulation of Bifidobacterium lactis for incorporation into soft foods

Autor: L. D. Mcmaster, S. A. Kokott, Paul Slatter
Rok vydání: 2005
Předmět:
Zdroj: World Journal of Microbiology and Biotechnology. 21:723-728
ISSN: 1573-0972
0959-3993
DOI: 10.1007/s11274-004-4798-0
Popis: Micro-encapsulation of the probiotic micro-organism Bifidobacterium lactis isolated from a bio-yoghurt starter culture, was carried out using a mixture of hydrated gellan and xanthan gums. Rheological studies showed that the gum mix was suitable for encapsulation of B. lactis, for incorporation into soft foods/beverages. The gel behaved as a non-Newtonian material, and the flow curve fitted well to the Herschel–Bulkley model. The average yield stress of the gum was 1.515 Pa, indicating gum stability, and the yield stress range was 1 Pa over a temperature range of 35–50 °C. Almost constant minimum gum viscosity occurred between 46 and 61 °C. Oval/round capsules were synthesized manually using a monoaxial gum flow through a 27.5 G bevelled needle, together with a superposed air stream (air knife technique). The diameter of the capsules, measured using laser diffractometry, varied from 20 to 2200μm, with 50% of the capsules having a diameter of ≤637 μm. Numbers of viable B. lactis in the capsules were estimated using high power ultrasound (20 kHz). By using a concentrated inoculum of B. lactis, microcapsules containing log10 11–12 c.f.u. g−1 were synthesized. Apart from the anaerobic culturing of B. lactis, all other work was done in the presence of atmospheric oxygen. The organism exhibited a high degree of oxygen tolerance. A 21-day survival study of immobilized cells in 1 M sodium phosphate buffer (pH 7) stored at either 4 or 22 °C indicated that B. lactis survived in excess of log10 11 c.f.u. g−1 microcapsule. This technique represents a suitable means of supplying viable probiotics to the food and/or pharmaceutical industries.
Databáze: OpenAIRE
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