Co‐extrusion and extrusion microencapsulation: Effect on microencapsulation efficiency, survivability through gastrointestinal digestion and storage

Abstract Probiotic is a functional food ingredient that is commonly used in the manufacturing of fermented dairy products and vegetable‐based foods. The consumption of probiotics has been claimed to confer health benefits to the host. However, probiotic cells are sensitive to harsh environments such as extreme pH and enzymes in the gastrointestinal tract. Hence, the microencapsulation technique is often adopted to shield probiotics from the outer environment. This review introduces a more advanced extrusion technique called co‐extrusion, which has been used to microencapsulate probiotics over the last few years. Both co‐extrusion technique and extrusion technique in microencapsulating probiotics were discussed extensively in this article. Furthermore, the impact of encapsulating probiotics in contrast with unencapsulated cells was also presented. This review highlighted some of the factors that might cause low viable cell count during microencapsulation and large microbead size. Lastly, the survivability of encapsulated probiotics in gastrointestinal digestion and storage under different temperatures were evaluated and the importance of probiotic microencapsulation was also emphasized. Practical Applications The detailed information on extrusion and co‐extrusion techniques for probiotics microencapsulation is presented in this review. This information is useful for researchers and industrialists in understanding and applying both encapsulation techniques on probiotics for different purposes. Through this paper, the readers would also gain more insight into the factors affecting the viability and microbead size of the encapsulated probiotic to further optimize the extrusion and co‐extrusion encapsulation process. Furthermore, the ideal storage temperature and additional drying process for the encapsulated probiotic identified in this review would open opportunities for industrialists to produce functional probiotic products with a high viable cell count.