Application of spray-drying and freeze-drying for microencapsulation of lactic acid bacteria: A review

Lactic acid bacteria (LAB) are well known for the production of fermented foods and their beneficial effects on consumers. However, they are very sensitive to environmental conditions, and their viability and functionality can be affected during different processing methods and storage. Therefore, encapsulation is essential to avoid injuries to bacterial cells and improve their survivability. Freeze-drying and spray-drying are two commonly used drying techniques for microencapsulation. Freeze-drying has been the conventional drying process for encapsulation and production of bacterial cultures in dried form, but it has some limits, such as low production yield and longer drying time. On the other hand, spray-drying technique has benefits such as fast, higher, and continuous productivity. Nowadays, due to increasing urbanization and consumer awareness, the beneficial LAB is dried in various food matrices apart from dairy food to produce functional food powders in ready-to-reconstitute form. These products have beneficial effects on live microbes as well as nutritional and functional properties of carrier media. This article provides a comprehensive overview of the application of freeze-drying and spray-drying methods for the encapsulation of LAB. It highlights the importance of the encapsulation of LAB and the production of functional probiotic food powders using different wall materials.