Microencapsulation of phenolic extracts in calcium alginate beads for nutraceutical applications

Bioactive ingredients are generally prone to degradation, both during storage and food processing, as many of them are physically, chemically and/or enzymatically instable leading to their degradation or transformation with the consequent loss of bioactivity. To overcome these limitations microencapsulation emerges as a reliable response to protect and stabilize bioactives (or extracts containing them), also offering the possibility of a controlled or targeted delivery [1]. The encapsulation materials, productive process, microcapsule’s morphology and ultimate application conditions are the most important factors to be taken into account when des igning a novel microencapsulated product, together with stability and functional properties issues. Moreover, to obtain a successful product, the achievement of high encapsulation yields, process and release profile reproducibility and overcome microcapsule’s aggregation, should be guaranteed. For food applications the used materials must be considered “generally recognized as safe” (GRAS ) and be, preferably, biodegradable. Both EU through the EFSA and the US through FDA have many strict rules about material usage for food applications. In this context, the most commonly used materials are natural or natural-derived polymers. Among them, carbohydrate polymers (e.g. starch and cellulose and their derivatives), plant exudates and extracts (e.g. gum, galactomannans, pectins and soybean polysaccharides), marine extracts (e.g. carrageenan and alginate), microbial and animal derived polysaccharides (e.g. xanthan, gellan, dextran and chitosan) and proteins were tested for these purposes. In what concerns microencapsulation processes, a set of techniques are available (e.g., coacervation, extrusion, emulsion based process, liposomes etc.). Nevertheless, spray -based processes are the most commonly used by academia and industry. They present the advantages of being flexible and economically competitive, allowing a continuous production [2]. In this work the use of microencapsulation to protect natural extracts will be demonstrated with a case study comprising the development of a nutraceutical formulation based on gelatine incorporating alginate microspheres enriched with bioactive phenolic extracts obtained from wild Fragaria vesca L.