L. casei ATCC 393-loaded capsules based on alginate and
gelatin had been prepared by extrusion technology and
the capsules were spherical, smooth-surfaced and nonaggregated
with a diameter of (4.0¡0.3) mm.
Microencapsulation could increase the live cell numbers
of L. casei ATCC 393 to 108 CFU?g21 in the wet state of
the capsules. The behavior of four samples was quite similar
at low relative humidity (33%, 52%) and the value of
the ratio of weight change reached 93%. The four samples
(S1, S2, S3 and S4) were observed to shrink in SGF. The
state of capsules treated with sodium citrate (S3, S4) in SIF
was not investigated because they disintegrated within
0.5 h. The capsules initially shrank then swelled and
finally, broke into pieces with an increase in pH and
behaved differently in media with different ion intensities.
The introduction of gelatin weakened the stability of capsules
compared with the alginate ones. Cells of L. casei
ATCC 393 could continuously be released from the
microcapsules under acidic condition (pH 1.2) to neutral
conditions (pH 6.8) and the release amounts and speeds of
L. casei ATCC 393 cells in neutral medium were much
higher and faster than in acidic condition. The results of
this study indicate that alginate-gelatin capsules can be
used for administering viable lactic acid bacteria.