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Observations on nitrile production during autolysis of kale and swedes, and their stability during incubation with rumen fluid
Author(s) -
Forss David A.,
Barry Thomas N.
Publication year - 1983
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.2740341007
Subject(s) - glucosinolate , incubation , autolysis (biology) , rumen , nitrile , chemistry , brassica , food science , biochemistry , zoology , agronomy , biology , fermentation , organic chemistry , enzyme
A method was modified for quantitatively measuring total nitriles produced from glucosinolate degradation during autolysis of kale and swede plant tissue. Nitrile production from New Zealand Medium Stem kale was less at pH 7.5 (0.28 mol mol −1 glucosinolate) than at pH 5.7 (0.57 mol mol −1 glucosinolate). Lower levels were produced from Maris Kestrel kale, due both to a lower glucosinolate content and to reduced conversion of glucosinolate to nitriles. The amount of nitrile obtained on conversion of glucosinolate tended to be reduced by growing New Zealand Medium Stem kale in soil of low SO 4 ‐S concentration, due to a reduction in plant glucosinolate content. Nitrile production from swede tissue was 0.3–0.5 mol mol −1 glucosinolate. Nitriles produced from swedes were rapidly degraded upon incubation with rumen fluid (4 h), whereas nitriles produced from kale remained stable for incubation periods up to 23 h. The high rate of conversion of glucosinolate to nitriles coupled with their stability in rumen fluid suggests that, in addition to goitrogenic properties, nitrile formation also deserves attention in the nutrition of ruminant animals fed kale diets. Of the four brassica diets tested, New Zealand Medium Stem kale is considered the most likely to cause nutritional problems (depressions in intake and reproduction) from nitrile production, and a method of testing this is suggested.