麦芽中的N-亚硝基二甲胺前体

N-nitrosodimethylamine precursors in malt.

作者信息

Wainwright T, Slack P T, Long D E

出版信息

IARC Sci Publ. 1982(41):71-80.

Abstract

NDMA is formed in malt because NOx reacts with certain amines in germinated barley when it is kilned. Hordenine is the major precursor of NDMA, although gramine and sarcosine can possibly contribute minor amounts. The hordenine is formed in the developing seedling. The amount of hordenine present in unkilned malts, made using a variety of malting techniques, is always much more than sufficient to account for NDMA formation. Malting techniques which inhibit hordenine breakdown during kilning decrease NDMA formation. Nitrosated intermediates formed from hordenine on treating with NOx at relatively low temperatures (ca 40 degrees C), can be separated by HPLC. They give NDMA on heating with additional NOx. The conditions under which the intermediates are formed and under which they are converted to NDMA correspond to the observed pattern of NDMA formation during kilning. The effects of sulfuring at different times can be explained by the effects on formation and breakdown of the intermediates.

摘要

N-亚硝基二甲胺（NDMA）在麦芽中形成，因为在烘焙发芽大麦时，氮氧化物（NOx）会与其中的某些胺发生反应。大麦碱是NDMA的主要前体，尽管禾草碱和肌氨酸可能也会少量促成其形成。大麦碱在发育中的幼苗中形成。使用多种制麦技术制得的未烘焙麦芽中，大麦碱的含量总是远超过足以解释NDMA形成所需的量。抑制烘焙过程中大麦碱分解的制麦技术会减少NDMA的形成。在相对低温（约40摄氏度）下用NOx处理大麦碱形成的亚硝化中间体，可以通过高效液相色谱法（HPLC）分离。它们在与额外的NOx一起加热时会生成NDMA。中间体形成的条件以及它们转化为NDMA的条件与烘焙过程中观察到的NDMA形成模式相符。不同时间进行硫磺处理的效果可以通过其对中间体形成和分解的影响来解释。