4. Conclusion
Microencapsulated powders of probiotic bacteria L. plantarum
was produced by freeze drying and spray drying techniques.
The moisture content of the spray dried powder was lower
than freeze dried powder. Morphology of the freeze dried
powders showed porous, spongy, flake like structure with
irregular size and shape. In contrast, spray dried encapsulated
powders of WPI + SA showed smooth surface and
DWPI + SA had wrinkled rough surface. Spray drying method
produced almost 9–12% less survival of cells compared to
freeze drying method (92–96%). DWPI + SA improved the survival
of probiotics than the WPI + SA and the highest cell viability
of 96% was obtained from freeze drying method while 87% was obtained by spray drying method. In simulated
acidic conditions, DWPI + SA showed better tolerance for both
drying methods and in the case of bile juice condition spray
dried encapsulated cells showed better stability than the
freeze dried encapsulated cells. This study indicated that
DWPI + SA wall material provided better protection as well
as sustained and controlled release of probiotics in acidic
and bile conditions. Thus it can be concluded that denatured
whey protein isolate and sodium alginate wall material provides
higher survival after processing and better protection
of cells in simulated gastric solutions.
Acknowledgment
We gratefully acknowledge the Department of Science and
Technology (DST), Government of India for the financial support
and Women Scientist Fellowship (WOS-A) to Rajam,
which enabled this work to be carried out. Authors wish to
thank Dr. M. C. Varadaraj, Head, HRD, CFTRI and Mr. K. Anbalagan,
CIFS, CFTRI for their help.