Physicochemical, Microstructural, and Release Profile of Gallic Acid and Hesperetin Rich Phenolic Extract in Polysaccharide and Protein-Based Complex Coatings

The influence of simple and complex carrier agents on the physicochemical, flow, and in vitro release properties of the encapsulated phenolic-rich extract from lemon myrtle leaves was investigated in this study. Polysaccharide-based complex coating (maltodextrin: gum arabic) offers the highest encapsulation efficiency (EE) resulting in maximum retention of phenolic compounds and antioxidant properties as compared to other coatings. However, all of the coatings provided above 97% of EE and passable/poor flow properties. The lightness of encapsulated extract was increased upon the incorporation of a protein-based coating with maltodextrin. The pure and encapsulated extracts indicate amorphous nature with a little degree of crystallinity. A similar release profile was observed for most of the samples in food simulants, initially slowly release and gradually increase to maximum release at around 36 h and then slowly decrease the release rate/availability of phenolics. All of the samples release the highest quantity of phenolics in lipophilic/fatty food simulant. In vitro analysis illustrate that the percent release of phenolics from an encapsulated sample can depend on the selection of coating and release medium. Therefore, appropriate coating material selection and optimization should be performed to get the desired output from the encapsulation of phenolic-rich extract. Polysaccharide and protein-based complex coatings enriched with phenolics could be applicable for the development of functional food products and nutraceuticals.