小麦制粉产品稳定碳、氮同位素组成特征

摘要

[目的]小麦制粉产品稳定同位素指纹相对于全粒粉是否存在分馏效应,这些产品能否用于小麦的产地溯源,以及利用稳定同位素是否能实现对小麦制粉产品来源地的鉴别还不清楚.系统分析全麦粉及各制粉产品中碳、氮同位素在地域间、基因型间的差异,揭示小麦制粉产品碳、氮同位素的组成特征及相关性,为小麦及其制品产地溯源提供理论与技术支撑.[方法]2014年将3个不同基因型小麦品种(邯6172、衡5229和周麦16),种植于河北石家庄赵县、陕西杨凌区和河南省新乡辉县.每个地域3个小区,每小区面积10 m2,试验田按照当地小麦品种区域试验管理.2015年收获期于3个地域共采集27份小麦样品,小麦籽粒粉碎制得全麦粉;同时将小麦籽粒加工制粉,得到面粉、次粉和麸皮.利用元素分析-同位素比率质谱仪(EA-IRMS)测定全麦粉及制粉产品(麸皮、次粉和面粉)中的稳定碳、氮同位素.结合单因素方差分析及Duncan多重比较分析解析碳、氮同位素在不同地域、不同基因型以及不同制粉产品间的差异,结合皮尔逊相关分析及线性回归分析,解析不同种类样品碳、氮同位素的相关性.[结果]不同地域来源全麦粉及制粉产品中碳、氮同位素均有显著差异(P辉县>赵县,氮同位素在地域间变化趋势为辉县>赵县>杨凌;全麦粉、麸皮和面粉中碳同位素及各类产品中氮同位素在基因型间均无显著差异,次粉中碳同位素在邯6172和衡5229之间有显著差异;碳同位素在全麦粉和不同制粉产品间存在显著差异(PZhaoxian>Yangling. No significant difference was found between different genotypes in δ13C in whole wheat flour, bran and flour, and in δ15N in each category of wheat samples, significant differences were found in δ13C between wheat genotypes of Han 6172 and Heng 5229. Significant differences were also found in δ13C among different categories of wheat samples (P<0.05),δ13C was relatively enriched in flour and depleted in wheat shorts and bran, while no significant difference was found inδ15N among different categories of wheat samples. Significant correlations were found in δ13C and δ15N between different kinds of wheat samples (P<0.01).[Conclusion]There were significant differences in δ13C among different wheat milling fractions, but no significant differences in δ15N among different wheat milling fractions. Significant correlations were observed between different categories of wheat samples in δ13C and δ15N. Both δ13C and δ15N of whole wheat flour and milling fractions were characterized by geographical features, which could be used for identifying the geographical origin of wheat and its milling products.