In vitro intestinal lipolysis of emulsions based on starch granule Pickering stabilization

The effect of barrier properties on in vitro intestinal lipolysis of three different types of emulsions based on oil-in-water starch granule Pickering stabilization has been investigated including non-heat treated, heat treated (gelatinized) and heat treated and stored (retrograded) emulsions. The stability of starch covered oil-water interfaces towards in vitro intestinal lipolysis was correlated to the rate of lipid hydrolysis using a pH-stat method. The results were compared with a sodium caseinate stabilized emulsion. The shape and size of the starch granules were characterized by scanning electron microscopy and light scattering. The physical properties of the emulsions were characterized by a light scattering particle size analyzer and light microscopy. In all cases, Pickering emulsions showed lower extents of lipolysis compared to the protein stabilized emulsion. In addition, heat treated starch Pickering emulsions were more susceptible to lipolysis compared to freshly prepared emulsions with no heat treatment. This was thought to be due to the gelatinized starch barrier being more susceptible to amylase present in the pancreatin. The results of this study demonstrate the interfacial layer properties can affect the rate and extent of lipolysis.