A review of the microencapsulation techniques for the incorporation of probiotic bacteria in functional foods

Probiotic strains are claimed to confer health benefits to human organisms when consumed in adequate amounts. Thus, over the last decades there has been an increased interest in the production of functional foods containing probiotic bacteria. However, in order to display optimal probiotic functionality, these bacteria should survive through the gastrointestinal tract (GI) in high populations, reaching 10⁶-10⁷cfu (colony-forming unit)/g or mL at the end of product's shelf life. The food products that can be used as probiotic bacteria carriers exhibit limitations concerning the viability of the cells, associated with parameters such as the acidity of the food matrices or their processing and storage conditions. Moreover, the acid environment of the GI system may be crucial for their survival. Thus, techniques such as microencapsulation and enrichment with prebiotic substances are proposed for their protection. Aim of this review is to present the bacterial strains exhibiting probiotic properties, the microencapsulation techniques which are applied for their protection, as well as their advantages and disadvantages. Finally, the characteristics of the most important food products that have been used as possible matrices for microencapsulated probiotic cells are described.