Alginate-based encapsulation of extracts from beta Vulgaris cv. beet greens: Stability and controlled release under simulated gastrointestinal conditions

We obtained extracts from beet greens using conventional and ultrasound treatments. The work focused on betacyanins, betaxanthins and polyphenols from the extracts following the two distinct extraction protocols. These were used as the bioactive compounds in alginate capsules in order to follow patterns of controlled delivery in simulated gastrointestinal fluids. FTIR was performed to show the nature of interactions between excipient and bioactives. Swelling behaviour and mechanical characterization of the polysaccharide network showed that it remains firm in the harsh gastric conditions but exhibits soft consistency in the simulated environment of the small intestine. There is a direct relationship between mechanical characteristics, hence swelling of the beads, and release rates of bioactives within the in-vitro environment. Peppas-Sahlin equation was applied successfully to demonstrate that the relaxation contribution dominates with increasing time of observation, an outcome that confirms the role of swelling of the alginate capsules in bioactive compound release.