Preparation of powdered oil particles by spray drying of cellulose nanocrystals stabilized Pickering hempseed oil emulsions

Abstract

We are reporting the preparation of cellulose nanocrystal (CNC) particles stabilized Pickering hempseed oil-in-water emulsions and using them as feedstocks for the preparation of oil powders without using any other hydrophilic carrier agent. Oil powders were prepared in a spray drier by rapid evaporation of water. The effect of the ratio of HSO to CNCs was evaluated on the emulsion stability and droplet size of emulsified hempseed oil. A mass ratio of 18 g hempseed oil/g CNC or lower was found to be optimal for emulsion stability over 15 days and droplet size between 500 nm and 1–2 μm. The effective interfacial area coverage of oil droplets by CNCs was found to be fundamental for emulsion stability. For the first time, the spray drying of CNCs stabilized oil/water emulsion was used to produce stable encapsulated oil particles without any oil leakage. The microencapsulation efficiency was dependent on the hempseed oil/CNC mass ratio, which in turn influenced the effective coverage of oil droplets. The results suggested that about 10–14 layers of CNCs are required to effectively encapsulate hempseed oil droplets with minimal oil leakage. Less than eight theoretical layers of CNCs resulted in lower encapsulation efficiency with an increase of free-extractable oil. These results are of particular relevance in advanced formulations containing hempseed oil and other compounds that can be potentially stabilized and/or microencapsulated by CNCs.