Conjugated linoleic acid loaded starch-based emulsion nanoparticles: In vivo gastrointestinal controlled release

Conjugated linoleic acid (CLA) exhibits poor water solubility and a high sensitivity to oxidation, resulting in a loss of bioactivity. More importantly, the best absorption site of CLA is small intestine. Thus, developing a carrier system for encapsulating CLA to enhance its solubility and stability, and retaining its bioactivity is required. This study used octenyl succinic anhydride (OSA) modified starch and xanthan gum (XG) as a complex carrier of CLA to protect it, reduce material loss in the stomach (a non-absorptive site for CLA), and improve its utilization in the intestinal tract. The OSA starch-XG complex carrier acted as the aqueous phase, while CLA acted as the oil dispersal phase. The rheological properties, particle size, and emulsion stability were studied, and the preferred emulsion solid content (5-20 g/100 g) and the range of OSA starch: XG ratios (60:1-100:1) in wall materials were identified. The effect of process parameters on encapsulation efficiency of nanoparticles for CLA was studied, in order to determine the optimal ratio of core material: wall material, solid emulsion content, and inlet air temperature to be 1:4, 10 g/100 g, and 170 degrees C, respectively. The encapsulation efficiencies were all above 97%, indicating that CLA was effectively entrapped within the internal nanoparticle structure. In addition, an in vivo animal experiment using confocal fluorescence microscopy indicated that CLA loaded emulsion nanoparticles were rarely released in the stomach of rats, and that most CLA loaded emulsion nanoparticles were released after entering the small intestine. The nanoparticles presented sustained release performance, and could be used as a nanocarrier in the food encapsulation of functional ingredients, as well as in the nutraceutical and pharmaceutical industries.