Tannins and polyphenols in carob pods (<i>Ceratonia siliqua</i>)

Abstract

Abstract Separation of condensed tannins from sugars and low‐molecular weight polyphenols was achieved by cold‐water extraction of carob pod meal. The condensed tannins were isolated by subsequent hot‐water extraction of the meal and analysed by permanganate titration, alkaline hydrolysis and fusion, paper chromatography, reactions for the presence of leuco‐anthocyanins and catechins. They were not soluble in commonly used tannin solvents. Although the presence of leuco‐anthocyanins and flavanols was shown by general reactions, no monomeric substances of this group were detected in ripe carobs. Extracts from green carobs contained several catechins and leuco‐anthocyanins, that may be regarded as possible precursors of condensed tannins. Gallic acid was the main constituent of the low‐molecular weight fraction obtained from ripe carobs and which was soluble in organic solvents.