Enzyme Stability of Microencapsulated Bifidobacterium animalis ssp. lactis Bb12 after Freeze Drying and during Storage in Low Water Activity at Room Temperature

Abstract

Stability of enzymes such as β-galactosidase (β-gal), β-glucosidase (β-glu), lactate dehydrogenase (LDH), pyruvate kinase (PK), hexokinase (HK), and ATPase of microencapsulated Bifidobacterium animalis ssp. lactis Bb12 after freeze-drying and after 10 wk of storage at low water activity (a(w)) at room temperature was studied. Bacteria were microencapsulated using alginate formulation with or without mannitol fortification (sodium alginate and mannitol [SAM] and sodium alginate [SA], respectively) by creating gel beads followed by freeze drying. Two types of dried gel beads were then stored at low a(w), such as 0.07, 0.1, and 0.2; storage in an aluminum foil was used as control. All storage was carried out at room temperature of 25 °C for 10 wk. Measurement of β-gal, β-glu, LDH, PK, HK, and ATPase (with or without exposure to pH 2.0 for 2 h) activities was carried out before freeze drying, after freeze drying, and after 10 wk of storage. There was a significant decrease in almost all enzyme activities, except that of PK. SAM and SA showed no different effect on maintaining enzyme activities during freeze drying. Storage for 10 wk at room temperature at various low a(w) using SAM and SA system had a significant effect on retention of most enzymes studied, except that of PK and LDH. Storage at a(w) of 0.07 and 0.1 was more effective in maintaining enzyme activities than storage at a(w) of 0.2 and in an aluminum foil. However, mannitol fortification into alginate system did not significantly improve retention of enzymes during 10 wk of storage.

Effect of Drying Process, Encapsulation, and Storage on the Survival Rates and Gastrointestinal Resistance of L. salivarius spp. salivarius Included into a Fruit Matrix

“…The porous envelope of the encapsulated microorganisms could confer a protection against high temperatures, avoiding the favorable response to thermal stress, but seemed to not protect the cells against the oxidation or the water migrations during the storage. This was in agreement with other authors that observed alginate capsules were not able to protect encapsulated microorganisms from water migrations [27] or oxidation reactions [28] during storage. The obtained p-values of variables (drying, encapsulation, and storage) and their interactions were in all cases 0.0000.…”

“…1.39 ± 0.05 (27) 0.8 ± 0.5 (20) 0.3 ± 0.7 (10) t 4 0.5 ± 0.4 (8) 0.7 ± 0.2 (14) 0.4 ± 0.4 (9) 0.3 ± 0.3 (8) 0.2 ± 0.3…”

Effect of Non-Dairy Food Matrices on the Survival of Probiotic Bacteria during Storage

“…In addition, the viability of L. rhamnosus GG formulated with flaxseed after storage for 14 months at 22 °C was reported to show a reduction of viability by more than 4 log cfu with a w 0.43, but a slight reduction of only 0.29 log cfu with a w 0.11 [ 23 ]. It has been shown that low water activity in a food carrier maintains the enzyme activity of bacteria during storage, which may contribute to improved survival [ 24 ]. While the work reported here did not measure water activity of the samples, it is reasonable to estimate that the samples produced would have equilbriated to water activities of approximatley 0.2 and 0.5 at 20 °C 20% RH or 30 °C 50% RH, respectively.…”

Role of Calcium Alginate and Mannitol in Protecting Bifidobacterium

“…Storage at low a w s (0.07 and 0.1) maintained high viability of bacteria during long-term storage at room temperature; however, this phenomenon depended on the type of sugars used as protectants: incorporation of mannitol in Ca-alginate improved the survival of Bifidobacterium animalis subsp. lactis Bb12 and preserved some glycolytic enzymes during long-term storage at room temperature and low a w (11,12).…”