Pickering emulsions based on food byproducts: A comprehensive study of soluble and insoluble contents

Hypothesis: Pickering emulsions can be produced using raw particles obtained from uncracked vegetal food byproducts as sole stabilizers. The complexity brought by these non-purified ingredients will be their strength since insoluble particles and soluble compounds shall display good complementary properties, at the interface and the continuous phase.

Experiments: Emulsions were monitored over a one-month storage as regards to oil droplet diameter as main indicator of stability. Then, two main studies were carried out: 1) on the whole powders (water binding capacity, dry matter and insoluble content, size and morphology); 2) on the soluble content (size, charge, pH, Brix degree, surface tension measurements).

Findings: All byproducts stabilized-emulsions were stable during storage. They display various oil droplet sizes with sugar beet < apple < oat. Direct observation of the oil-water interfaces showed adsorption of the solid particles, and some voids corresponding to soluble elements from the byproducts' powders. The latter displayed surface-active properties. The insoluble particles are driving the oil droplet size and protecting against coalescence while soluble compounds can also adsorb at the interface, lowering droplet size, and also act as thickening agents from the continuous phase (pectins). Vegetal byproducts are thus meta ingredients, able to stabilize clean-label emulsions.