Nanotechnology for encapsulation and release of natural bioactive compounds

Promotion of health and prevention of disease through improved nutrition demands the development of food-grade delivery systems, including active packaging and edible structures, to encapsulate, protect and deliver bioactive components. In particular, volatile substances with bioactive features are of great interest and their efficient encapsulation and controlled release represent a major challenge, considering their high fugacity and liability towards environmental factors. Conventionally, studies involve the dispersion of the active agent in carriers with limited surface areas (e.g. polymer films and layers), with considerable losses during production and storage. Furthermore, the release of active substances from these structures is mainly based on concentration-dependent passive diffusion. Nanotechnology offers a wide range of innovative approaches in order to troubleshoot the drawbacks associated to encapsulation and controlled release of bioactive compounds. Because of their submicron-scale and the consequent large surface-to-mass ratios, nano-structured materials offer a number of additional advantages, such as being more responsive to changes in the surrounding atmosphere, which allows for a more specific triggered release, yet protecting the active molecules from environmental factors. In this report, special attention will be addressed to recent developments on nanofibrous membranes, fabricated by means of electrospinning technique, as encapsulation and controlled release systems of volatile bioactive compounds. The production of these nano-structured materials is very simple, cheap and recently it has been demonstrated that they can overcome several of the problems related to volatiles encapsulation, therefore representing an interesting solution for example to the food-packaging industry.