Carter James F, Yates Hans S A, Tinggi Ujang
Queensland Health Forensic and Scientific Services, P.O. Box 594, Archerfield, Queensland 4108, Australia.
J Agric Food Chem. 2015 Jun 24;63(24):5771-9. doi: 10.1021/acs.jafc.5b01526. Epub 2015 Jun 10.
This study presents the stable isotopic and elemental compositions of single-origin, roasted coffees available to retail consumers. The δ(13)C, δ(15)N, and δ(18)O compositions were in agreement with those previously reported for green coffee beans. The δ(15)N composition was seen to be related to organic cultivation, reflected in both δ(2)H and δ(18)O compositions. The δ(13)C composition of extracted caffeine differed little from that of the bulk coffee. Stepwise discriminant analysis with jackknife tests, using isotopic and elemental data, provided up to 77% correct classification of regions of production. Samples from Africa and India were readily classified. The wide range in both isotopic and elemental compositions of samples from other regions, specifically Central/South America, resulted in poor discrimination between or within these regions. Simpler X-Y and geo-spatial plots of the isotopic data provided effective visual means to distinguish between coffees from different regions.
本研究展示了零售消费者可获取的单一产地烘焙咖啡的稳定同位素和元素组成。δ(13)C、δ(15)N和δ(18)O组成与先前报道的生咖啡豆的组成一致。δ(15)N组成被认为与有机种植有关，这在δ(2)H和δ(18)O组成中均有体现。提取的咖啡因的δ(13)C组成与整粒咖啡的δ(13)C组成差异不大。使用同位素和元素数据进行刀切检验的逐步判别分析，对生产地区的正确分类率高达77%。来自非洲和印度的样品很容易被分类。来自其他地区，特别是中美洲/南美洲的样品，其同位素和元素组成范围广泛，导致这些地区之间或内部的区分效果不佳。同位素数据的更简单的X-Y图和地理空间图提供了有效的直观手段来区分来自不同地区的咖啡。
