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Cellulase inhibition by tannins in the testa of field beans ( Vicia faba )
Author(s) -
Griffiths D. Wynne,
Jones D. Iorwerth H.
Publication year - 1977
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.2740281106
Subject(s) - tannin , cellulase , vicia faba , solubility , condensed tannin , food science , botany , chemistry , proanthocyanidin , cellulose , biology , polyphenol , biochemistry , antioxidant , organic chemistry
The testa of field bean varieties with coloured flowers contained 4–8 % tannin (measured as total phenolics) compared with less than 0.6 % in the testa of white flowered varieties. The tannin present in whole beans was almost entirely contained in the testa. The presence of high levels of tannin reduced in vitro digestibility and solubility in cellulase solutions of the testa and addition of high tannin testa decreased the solubility of cotyledon protein in acid pepsin. Water extracts of the testa from coloured‐flower varieties inhibited the action of fungal cellulase and reduced the in vitro digestibility of white flowered testa and cellulose. A highly significant relationship ( r = −0.93***) was found between the tannin content and solubility in cellulase of testa for a range of 24 varieties. It is concluded that the effect of testa tannins on in vitro digestibility can be mainly attributed to their effect on cell wall digesting enzymes rather than an effect on protein solubility per se .