Probiotic encapsulation by cross-linking method. (a) Preparation of cellulose-based encapsulation films by cross-linking CMC and HEC with CA. Adapted from Ref. [88], with permission of Elsevier Ltd., 2019. (b) The enhanced storage stability of probiotics after ACFP composite capsule encapsulation. Black: AG, Ca-alginate gel with L. plantarum. Red: ACG, Ca-alginate/cellulose gel with L. plantarum. Blue: ACFP, Ca-alginate/cellulose/cryoprotectant gel with L. plantarum. Adapted from Ref. [37], with permission of Elsevier Ltd., 2019. (c) Scheme illustrating the morphology of ACMS encapsulated probiotics and the pH-responsive mechanisms. Adapted from Ref. [80], with permission of American Chemical Society, 2018.