Fragrance encapsulation in chitosan particles

 The method employed to prepare chitosan nanoparticles has been emulsion and ionic gelation, which is based on the micelle formation and the electrostatic interactions that take place between chitosan and sodium tripolyphosphate (TPP). DLS technique has been used to analyse the size, the Z potential and PDI values. Moreover, the size has been studied with SEM. Degradation of chitosan nanoparticles has also been characterised by TGA technique. Optimised nanoparticles without terpinolene have a diameter of 299.4 nm and up to 448.3 nm when terpinolene was encapsulated inside the nanoparticles.

Fragrances are chemical compounds used in a huge range of fields, for instance in personal care products and textiles. These chemicals must be lipophilic, volatile and small (molecular weight less than 300 Da) in order to be perceptible by humans. The fact that they are volatile, makes them able to escape from their fluid or even solid state into the air. 

Human beings have on the roof of the nasal cavity a mucous membrane (sensory tissue), called olfactory epithelium. Fragrance molecules get to this area in the air we breathe. Next, those molecules are dissolved in the mucous and then couple to smell receptors. The smell receptors are expressed on the plasma membrane of the sensory cells, which send nerve impulses to the brain. Finally, the brain learns to recognise different substances only by the odour.