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Factors affecting n‐nitrosodimethylamine development in germinated barley
Author(s) -
Haley James,
Palmer Godfrey H.
Publication year - 1985
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.2740360608
Subject(s) - chemistry , endosperm , methionine , germination , food science , embryo , biochemistry , biology , botany , amino acid , microbiology and biotechnology
Study of germinated (malting) barley showed that there was no direct correlation between hordenine levels and the development of N‐nitrosodimethylamine (NDMA) during kilning. Results also indicated that the repression of NDMA formation by sulphur dioxide was more likely to be linked to a chemical reaction with the nitrosating species and changes in oxygen activity rather than to a simple pH effect. Tyrosinase reduced hordenine levels in vitro. After nitrosation, the tyrosinase‐hordenine digest produced more NDMA than equivalent digests of inactivated tyrosinase and hordenine. This effect of tyrosinase was enhanced by catechol and reduced by sodium metabisulphite. Preliminary studies indicated that both embryo and endosperm food reserves are utilised for hordenine production by the embryo. Further investigations with excised barley embryos suggested that while L‐tyrosine treatment increased hordenine production, L‐methionine treatment increased the potential of the embryos to form NDMA.