Protection of heat-sensitive probiotic bacteria during spray-drying by sodium caseinate stabilized fat particles

• Fat particles and Lactobacillus cells were co-encapsulated in NaCas microcapsules.
• Co-encapsulated fat increased survival of Lactobacillus cells during spray-drying.
• Co-encapsulated fat reduced cellular damage to Lactobacillus during spray-drying.
• Melting enthalpy of fat positively correlated with survival of Lactobacillus cells.

The objective of this research was to investigate the possibility of co-encapsulating low melting point fat (LMF) with probiotic bacteria to minimize their heat damage during spray-drying. Three Lactobacillus isolates (LB1, S64 and K67) as potential probiotic bacteria were spray-dried in 10% w/v sodium caseinate (NaCas) in the presence of either LMF or vegetable oil as a control. Addition of LMF, but not vegetable oil, significantly increased the survival of isolate LB1 (from 15 % to 63 %) in the spray-dried powders. Differential scanning calorimetry (DSC) results showed that the melting enthalpy increased with the concentration of LMF, which is in accordance with the survival rate of LB1 after spray-drying. In addition, isolates LB1 and K67 co-encapsulated with LMF showed improved survival on NaCl-MRS agar compared to the control, indicating a reduction in their cellular damage. The current study demonstrated that LMF was an effective thermal protectant during spray-drying of probiotic bacteria.

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