Supercritical carbon dioxide interpolymer complexes improve survival of B. longum Bb-46 in simulated gastrointestinal fluids

Mapitsi S. Thantsha a, Thomas E. Cloete , Francis S. Moolman , Philip W. Labuschagne

Gastric acidity is the main factor affecting viability of probiotics in the gastrointestinal tract (GIT)


In this study an investigation of survival in simulated gastrointestinal fluids of Bifidobacterium longum Bb-46 encapsulated in interpolymer complexes formed in supercritical carbon dioxide (scCO2) was carried out. Bacteria were exposed sequentially to simulated gastric fluid (SGF, pH 2) for 2 h and simulated intestinal fluid (SIF, pH 6.8) for 6 or 24 h.

Total encapsulated bacteria were determined by suspending 1 g of product in SIF for 6 h at 37 °C prior to plating out. Plates were incubated anaerobically at 37 °C for 72 h.



  • The interpolymer complex displayed pH-responsive release properties,   with little to no release in SGF and substantial release in SIF.
  • There was a  limited reduction in viable counts at the end of exposure period due to encapsulation.
  • Protection efficiency of the interpolymer complex was  improved by addition of glyceryl monostearate (GMS). Gelatine capsules delayed release of bacteria from the interpolymer complex thus minimizing time of exposure to the detrimental conditions.
  • Interpolymer complex encapsulation  showed potential for protection of probiotics and therefore for application in food and pharmaceuticals.