An enhanced pH-sensitive carrier based on alginate-Ca-EDTA in a set-type W1/O/W2 double emulsion model stabilized with WPI-EGCG covalent conjugates for probiotics colon-targeted release

In this study, we demonstrated the role of W-1/O/W-2 double emulsion with alginate-Ca-EDTA system on the gastrointestinal digestion viability of Lactobacillus Plantarum strain liquid. The W-1/O/W-2 double emulsion was prepared by WPI-EGCG covalent conjugate nanoparticles with compartmented multiple-emulsion nature. The effects of preparation parameters containing polyglycerol polyricinoleate content, oil fraction, and WPI-EGCG covalent conjugate particle concentration on the formation of W-1/O/W-2 double emulsions were systematically studied. Then, the rheological properties of alginate-Ca-EDTA system in the external aqueous phase of the W-1/O/W-2 double emulsions as the pH changes were investigated. The W-1/O/W-2 double emulsion maintained in the hydrogel state at pH below 4.0 because of Ca2+ coupled with G residues of alginate. In contrast, the W-1/O/W-2 double emulsion transformed to solution state at neutral pH condition, which caused the dissociation of Ca2+ from the Ca-alginate hydrogel and resulted in Ca-EDTA chelation. A pH-sensitive carrier based on an alginate-CaEDTA system in a set-type W-1/O/W-2 double emulsion model was exploited by regulating the release of Ca2+. Based on the pH-sensitive alginate-Ca-EDTA system and middle oil phase resistance, such a double emulsion supplied a colon-targeted release carrier for the Lactobacillus Plantarum strain liquid encapsulation into inner aqueous phase with the functional protection effect. The results offer a promising strategy for probiotics strain liquid encapsulation of double emulsion delivery systems in oral applications of foods (such as yogurt, fruit juice or cheese) and pharmaceuticals.