Starch based formulation for colon delivery of probiotics

Abstract: The interest in probiotics has grown in the last few years. In addition to being effective in treating and preventing acute diarrhea, there are indications that it might be possible to use probiotics to prevent other diseases such as colon cancer. The challenge with probiotics is that for it to have any effect, enough viable bacteria must reach the colon. To deliver live probiotics to the colon, it is necessary to protect the bacteria in some manner as most of them cannot survive the harsh environment in the gastrointestinal tract. A formulation consisting of starch microspheres with the bacteria encapsulated in the starch matrix was investigated. Starch microspheres were made by an aqueous two-phase system, with dissolved starch as the internal phase and dissolved polyethylene glycol (PEG) as the external phase. To crystallize the starch, the samples were incubated at 6 °C followed by 37 °C. Two different average molecular weight PEGs and several different PEG concentrations, as well as three different acid hydrolyzed waxy starches were investigated to find the best combination. 13 wt% PEG 2 000 000 and acid hydrolyzed waxy maize starch was chosen to produce microspheres containing microorganisms. Microorganisms of the type strain Lactobacillus reuteri DSM 20016 were successfully encapsulated in microspheres; however the freeze drying process of the bacteria prior to encapsulation killed most of them. The microspheres were analyzed with a simulated in vitro intestinal digestion. The work done in this project was very early explorative phase and a lot of work is needed to optimize the production process, and the freeze drying of the microorganisms.