Protective approaches and mechanisms of microencapsulation to the survival of probiotic bacteria during processing, storage and gastrointestinal digestion: A review

In recent years, there is a rising interest in the number of food products containing probiotic bacteria with favorable health benefit effects. However, the viability of probiotic bacteria is always questionable when they exposure to the harsh environment during processing, storage, and gastrointestinal digestion. To overcome these problems, microencapsulation of cells is currently receiving considerable attention and has obtained valuable effects. According to the drying temperature, the commonly used technologies can be divided into two patterns: high temperature drying (spray drying and fluid bed drying) and low temperature drying (ultrasonic vacuum spray drying, spray chilling, electrospinning, supercritical technique, freeze drying, extrusion, emulsion, enzyme gelation, and impinging aerosol technique). Furthermore, not only should the probiotic bacteria maintain high viability during processing but they also need to keep alive during storage and gastrointestinal digestion, where they additionally suffer from water, oxygen, heat as well as strong acid and bile conditions. This review focuses on demonstrating the effects of different microencapsulation techniques on the survival of bacteria during processing as well as protective approaches and mechanisms to the encapsulated probiotic bacteria during storage and gastrointestinal digestion that currently reported in the literature.