M. Sjöö, J. Bedi, A. Ali
Keywords: encapsulation, skin care, food, emulsion
Summary:A novel technology based on using particles of biological origin for stabilizing emulsions, so called Pickering emulsions, was recently developed. This technology was further employed to encapsulate different types of active substances. Advance development and refinement of the technology has been performed in order to suit different encapsulation purposes in areas within personal care, food and pharmaceuticals. The technology is being commercialized by Speximo AB, a spin-off from Lund University in Sweden. Using particles of biological origin is of high relevance, especially for the personal care and food sectors where the awareness regarding sustainability issues is increasing. The particles used were starch granules with a hydrophobic surface modification. The unique advantage compared to other types of particles is the ability of the starch granules to swell when attached to the surface of an oil droplet. This would cause a total coverage of the oil droplet surface. If, on the other hand, comparing with hydrocolloids in the molecular form, the barrier layer formed using the particle based technology would generally be thicker. However, the barrier also had totally different properties in terms of density and porosity. The ability to efficiently adjust and control the barrier properties has been demonstrated by measuring lipase digestion of encapsulated oil. The present technology has been shown to encapsulate substances with a strong off-flavor for taste masking using omega-3 oil as an example of a food application and penicillium as a pharmaceutical example. More recently, another strong tasting model oil was efficiently masked using the present technology and a certain barrier treatment compared to a commonly used system. Encapsulation of flavors and fragrances are relevant also for personal care and cosmetic applications. Since the technology was based on Pickering emulsion formation, encapsulation was highly efficient when performed directly in the emulsion system, both in traditional oil-in-water systems and in double emulsions. In addition to more general storage properties, the stability of a cosmetic active was investigated in an encapsulated system based on the present technology. The method used for analysis followed guidelines for pharmaceutical tests and the projected stability was 2.8 times higher than for a reference sample. For many applications it is beneficial to dry the encapsulate into an oil filled powder. The ability to dry emulsions and subsequently reconstitute the powder with water has been demonstrated. Even for a dried and reconstituted double emulsion, an encapsulated marker was retained at over 97%. The cosmetic feel and on-skin behavior of particle based creams was experienced as very positive in sensory tests. The cosmetic properties are highly important for the ability of an end product containing an active substance to reach the market. The present technology has shown capacity of both encapsulation and on skin delivery with a concurrent cosmetic feel. Furthermore, Pickering emulsions have been seen to substantially increase transportation of active substances through skin. Consequently, the present technology may find use in a range of products for topical use.