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The benefit of disaccharide protectants for maintaining viability and
@b-glucosidase activity of Bifidobacterium infantis UV16PR during
freeze-drying and storage in different food matrices was investigated.
Protectants used were cellobiose, lactose, sucrose and trehalose. At 5%
concentration, cellobiose showed the best protective effect during
freeze-drying. All protectants at 10% concentration significantly improved
the viability and retention of @b-glucosidase activity after freeze-drying
and storage in food matrices. Regardless of the protectant used, no
significant differences were observed after freeze-drying and storage for 2
weeks in milk, while in red-beet and grape juice, cellobiose and trehalose
significantly enhanced @b-glucosidase activity, viability and acid
tolerance. Viability of cellobiose and trehalose protected cells in juices
was comparable, whereas differences in retention of enzyme activity and
acid tolerance after the storage in different juices were observed. In
conclusion, various protectants increased the retention of @b-glucosidase
activity, viability and acid tolerance of freeze-dried B. infantis during
storage in different food matrices. In order to choose protectants for
probiotics for freeze-drying and food as probiotic carrier, not only their
effect on survivability, but also the enzyme activity retention should be
considered.
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