Gastrointestinal digestion and stability of submicron-sized emulsions stabilized using waxy maize starch crystals

Abstract

We prepared Pickering emulsions using tricaprylin (TC) and waxy maize starch nanocrystals (SNCs). The SNCs were obtained using an acid hydrolysis method and subsequently modified with octenyl succinic anhydride (OSA), to stabilize the water/TC interface. The particle size (PS) of fabricated OSA-SNCs was ∼42 nm, and contact angle of OSA-SNCs at the interface was determined as ∼90° using a gel trapping technique. Only 0.15 wt% OSA-SNCs in the continuous phase of the emulsion effectively saturated the surface of the TC droplets (5 wt%) to achieve a stable Pickering emulsions (PS, ∼0.5 μm). Theoretically, a TC droplet was covered with ∼450 OSA-SNCs at the saturation point. The excess amount (≥0.15 wt%) of OSA-SNCs used to prepare the Pickering emulsions did not affect the digestion of the emulsions during the in vitro study in simulated gastrointestinal fluids and the stability during the 15-days storage at various conditions (pH: 4, 7, and 11; temperature: 4, 25, and 37 °C). Based on the storage results, the Pickering emulsions stabilized with OSA-SNCs were good to be stored in neutral/basic conditions under refrigeration. This study may serve as a basis for further research that aims for development of foods, cosmetics, and drugs to incorporate lipophilic bioactives.