Tannin content of sorghum varieties and their role in iron bioavailability.

Abstract

The tannin content of 198 lines of sorghum grain samples from 2 locations was 10 to 2056 mg/100 g with less than 65 for about 50% and more than 400 for 5% of those. There were differences among varieties and locations and local varieties generally had more tannin than high-yielding and hybrid varieties. Availability of iron was studied with 12 normal and 13 anaemic men given sorghum flour containing tannin 20 or 136 mg/100 g. Results suggested that tannin was not important in determining availability of iron.ADDITIONAL ABSTRACT:Tannin content ranged from 10 to 2056 mg/100 g grain in 198 forms, including local and high-yielding varieties (HYVs) and hybrids, with HYVs having a significantly lower content than local varieties. About 50% of samples had <65 mg/100 g. Site effects were significant for 18 varieties grown at two sites. In studies with normal and anemic human subjects, iron availability for the latter was greater from low-tannin than from high-tannin varieties