Inhibition of Metal-Polyphenol Complex in Tea Fortified with Encapsulated Iron

Abstract

Fortifying tea with iron faces the formation of a blue complex between iron and polyphenols. These technical challenges were circumvented by encapsulating iron sulphate with walls of whey proteins and Eudraguard via spray drying. Three types of capsules were generated based on the quantity of enclosed iron, 5.1, 7.7, or 10.0 mg; the quantity of iron is proportional to the complex formation. The encapsulation process enhanced iron absorption by 73% compared to free iron. The iron-polyphenol complex formation in gallic acid and black tea solution was studied. The complex formation in two buffers, 2-(N-Morpholino)ethane sulfonic acid (MES), and [piperazine-N, N′-bis(2-ethanesulfonic acid)] (PIPES), in two pH, 5.5 and 6.6, and the situations of buffered and unbuffered gallic acid in 0.3 mM ferrous sulphate solution was analyzed. The most stable solutions were gained with gallic acid in MES at pH 5.5 and 6.6 and PIPES at 6.6.