Kafirin microparticle encapsulation of catechin and sorghum condensed tannins

To exploit the porous nature of previously developed kafirin microparticles, encapsulation of the bioactive polyphenols, catechin and sorghum condensed tannins, was investigated. The antioxidant release profiles of the encapsulated substances were studied under simulated gastric conditions. Kafirin microparticles encapsulating catechin or sorghum condensed tannins were similar in size to control kafirin microparticles (5-6 µm). TEM showed that kafirin microparticles encapsulating catechin had a rough porous surface. Microparticles encapsulating sorghum condensed tannins were irregular in shape, some apparently joined together, with a mixture of rough and smooth surfaces. Over a period of 4 h, catechin and sorghum condensed tannin encapsulated kafirin microparticles showed virtually no protein digestion but released approximately 70 and 50%, respectively, of total antioxidant activity. Thus, the use of kafirin microparticles to encapsulate catechin and sorghum condensed tannins has potential as an effective method of controlled release of dietary antioxidants.