Micron size and food grade pristine CaCO3particles were used to stabilize an oil in water Pickering emulsion. The particles also acted as nucleation sites for the subsequent crystallization of CaCO3with the addition of CaCl2and CO2gas as precursors. After the controllable crystallization process, a dense CaCO3shell with a few microns in thickness was formed. The CaCO3shell was proven to be calcite without the presence of crystallization modifiers. The crystallization speed and the shell integrity were controlled by manipulating the addition of CaCl2amount during the different crystallization stages, therefore the homogeneous nucleation in the bulk was almost inhibited and the heterogeneous nucleation at the oil-water interface on pristine CaCO3particles was the main contribution to the growth of the shell. The encapsulated limonene flavour in CaCO3capsules showed a prolonged release in neutral water at 85°C while a burst release at pH2 water as expected. The method is a simple and scalable process for creating inorganic core-shell capsules and can be used for producing food grade capsules for controlling flavour release or masking undesirable taste in mouth.Pickering emulsion templating was employed to prepare CaCO3core-shell capsules loaded with hydrophobic actives in large scale. The addition of CaCl2with controlled concentration and feeding rate into the reaction system played a key role to achieve robust CaCO3shell, in which the homogeneous nucleation in the bulk was almost inhibited and the heterogeneous nucleation at the oil-water interface on pristine CaCO3particles was the main contribution to the growth of the shell.imageLarge scale preparation of high quality CaCO3core/shell capsules was achieved. CaCO3particles was used as Pickering emulsion stabiliser and the nucleation sites. Homogeneous nucleation in the bulk was inhibited by control the addition of CaCl2. Without any additives, high pure CaCO3capsules showed prolonged flavor release..
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