engleski

Comparative analysis of different alginate-based immobilization systems for encapsulation of polyphenolic antioxidants from red raspberry leaves (Rubus idaeus L.) by electrostatic extrusion

Traditionally used in folk medicine for its health benefits, leaves of red raspberry (Rubus idaeus L.) present a rich source of bioactive compunds and contributes to an increase of the overall intake of bioactive compounds in the daily diet, so an effective supplementation form containing red raspberry leaves bioactives should be established. Up to date spray drying has been mainly used as a technique for the entrappment of polyphenolic compounds from various plant substrates. Since spray-drying requires complex equipment and high energy inputs, a need arises for development of an effective immobilization system applying a simple technique, such as electrostatic extrusion. The aim of this study was to encapsulate polyphenolic compounds from red raspberry leaves extract in different alginate-based matrices using electrostatic extrusion. For that purpose plain alginate, as well as caseine and chitosan reinforced alginate microbeads were evaluated in terms of encapsulation efficiency and release profiles of polyphenols in water. The release kinetics was determined by following total phenol content and antioxidant capacity during time period of 24h, where antioxidant capacity was measured by ABTS radical scavenging assay. The obtained results revealed the same difussion controlled release patterns for all samples. The majority of polyphenolic compounds are released during 10-15 min, while the encapsulation efficiency varied between 80.5 % for alginate and 84.4 % for chitosan-alginate microbeads. In addition to alginate-based microbeads described above, Ca-alginate microbeads containing dextrose as a filler substance were prepared by absorption of raspberry leaves extract compounds in blank Ca-alginate microbeads. In this case, somewhat lower encapsulation efficiency (77%) was determined, while diffussion rate of polyphenolic compounds was nearly the same. The results suggest the potential of alginate-based microbeads prepared by electrostatic extrusion to be used for delivery of bioactive compounds, and contribute to the development of novel functional food products, as well as antioxidant-containing supplements for pharmaceutical and cosmetic aplications.

alginate; chitosan; electrostatic extrusion; encapsulation; polyphenols

nije evidentirano