Encapsulation of Aqueous Components in Solid Fat Beads: Studies of a Model Dye and a Probiotic Culture

Solid fat beads containing aqueous droplets of either a water soluble dye (Brilliant Blue) or a suspension of viable probiotic bacteria (Bifidobacterium animalis ssp lactis) were produced by dropping a water‐in‐molten fat emulsion into cold water or onto a cold plate, respectively. Hydrogenated palm stearin beads containing 20 % dye solution were 4.6 ± 0.2 × 2.7 ± 0.4 mm and the average bead weighed 0.0103 ± 0.0003 g. The dye was completely released into an external aqueous phase after 24 h stirring at temperatures above the melting point of the fat but at temperatures where the fat was solid very little dye was released into an external aqueous phase. When a bacterial suspension was used as the internal phase of 20 % hydrogenated palm stearin/80 % palm kernel oil beads, the beads contained 8.44 log CFU/g. The encapsulated organisms were more resistant to acid stress than an unencapsulated control (loss of 0.7 versus 5.75 log CFU/g). This approach offers a way to protect probiotic bacteria during transit through the stomach. Practical application: by encapsulating bacteria in solid fat they become more resistant to acids. Small beads could be added to foods or swallowed as a pill as a way to deliver viable probiotic organisms to the lower digestive tract.