Effect of cooking on tannin and phytate content in different bean (Phaseolus vulgaris) varieties grown in Tanzania
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Date
2017
Journal Title
Journal ISSN
Volume Title
Publisher
Academic Journals
Abstract
Phytates and tannins are present in varying proportions in legume based foods. Investigation on the
effect of cooking on tannins and phytates was carried out on thirty eight raw and cooked bean
(Phaseolus vulgaris) varieties. Tannins were assayed by vanillin-hydrochloric acid method, while
phytates were determined by a method developed by Haugh and Lantzsch. There was a very high
significant difference (P≤0.00001) in the tannin concentrations between the raw and cooked bean
samples. The mean tannin content for the raw and cooked samples was 1.168±0.81 and
0.563±0.503%CE, respectively. Reduction of tannins after cooking ranged from 20%CE in M’mafutala to
81%CE in GLP 2 with an average reduction of 56.3%CE. Equally, there was a very high significant
difference (P≤0.0001) in the phytate concentrations between the raw and cooked bean samples. The
mean phytate content for the raw and cooked samples were 0.0219±002 and 0.0122±003 μg/mL,
respectively. Cooking reduced the anti-nutritional factors significantly (p≤0.0001). The extent of antinutritional
factors reduction varied between bean varieties. Cooking is therefore important for mineral
absorption during digestion process in humans as it makes the minerals less bound and hence
physiologically available.
Description
African Journal of Biotechnology Vol. 16(20), pp. 1186-1191, 17 May, 2017
Keywords
Beans, Phytates, Tannins, Minerals, Raw, Cooking, Bioavailability