Development, characterization and in vitro digestion of polysaccharide reinforced composite stimuli-responsive hydrogel encapsulating bioactive polyphenols from fruit peel waste

In this present investigation an indigenous hydrocolloid-based composite stimuli-responsive hydrogel carrier system was prepared for encapsulating bioactive polyphenols from discarded peels of Citrus reticulata which is an enormous organic waste of the fruit juice industry. Using the thermo-reversable gelation process, agar was combined with pectin or starch to create two formulations of hydrogel for encapsulating the polyphenols extracted from the peels. A maximum polyphenol encapsulation efficiency of 85.74% was achieved. The hydrogels containing polyphenols maintained their shelf life and successfully conserved more than 95% of the polyphenols at 35 °C without demonstrating significant degradation for a period exceeding 4 weeks. Various mechanical and physicochemical analyses were conducted on the produced hydrogels. Further, the release kinetics of polyphenols from gels through in vitro digestion were studied under a simulated gastrointestinal environment. The findings indicated that after 9 hours, ~77% of the encapsulated polyphenol had been released and the pattern of release was found to be stimuli-responsive and of controlled release type. In addition, the prepared hydrogel showed high hemocompatibility, bactericidal properties and ensured a significant level of antioxidant activity (>50%). As a result, this polyphenol encapsulating hydrogel formulation may be used to valorize the industry generated waste peels of C. reticulata.