Functional properties and bioaccessibility of alginate based phycocyanin-honey hydrogels

Food gels have become attractive due to their biocompatibility, environment-friendly characteristics, and wide array of medical and food applications. One of the main design principles of a functional food matrix is the encapsulation, protection, and controlled release of nutraceuticals. The present study utilized two products having great interest recently, phycocyanin and honey, which were embedded in a gel-type delivery system composed of different concentrations of alginate (0.5, 1.0, 1.5, and 2.0g/100 mL) and gelatin (7g/100 mL). The phycocyanin-honey gel balls (PHB) were characterized in terms of physical, rheological, textural, morphological, and sensory properties, as well as in vitro digestion, bio-accessibility, and total phenolic content release kinetics. The increasing alginate concentration significantly increased (p<0.05) total phenolic content. Also, increasing alginate ratios caused sheet-like inner layers observed in scanning electron microscopy (SEM) images. In vitro digestibility of phenolic content derived from both honey and phycocyanin was significantly improved (p<0.05) and protected from the mouth and gastric medium by hydrogel structures of alginate and gelatin. PHB showed high release (>≈85g/100 mL) and bio-accessibility (>≈84g/100 mL) of phenolic content in the intestinal medium. Consequently, alginate could be successfully used at 1.5g/100 mL concentration with gelatin to enhance the functionality and bio-accessibility of functional ingredients without affecting sensory properties.