Details

Autor(en) / Beteiligte

• Driscoll, Avery W.
• Howa, John D.
• Bitter, Nicholas Q.
• Ehleringer, James R.

Titel

A predictive spatial model for roasted coffee using oxygen isotopes of α‐cellulose

Ist Teil von

• Rapid communications in mass spectrometry, 2020-04, Vol.34 (7), p.e8626-n/a

Ort / Verlag

England: Wiley Subscription Services, Inc

Erscheinungsjahr

2020

Link zum Volltext

Quelle

Wiley Online Library Journals Frontfile Complete

Beschreibungen/Notizen

• Rationale Fraudulent region‐of‐origin labeling is a concern for high‐value, globally traded commodities such as coffee. The oxygen isotope ratio of cellulose is a useful geographic tracer, as it integrates climate and source water signals. A predictive spatial model (“isoscape”) of the δ18O values of coffee bean cellulose is generated to evaluate coffee region‐of‐origin claims. Methods The oxygen isotope ratio of α‐cellulose extracted from roasted coffee beans was measured via high‐temperature conversion elemental analyzer/isotope ratio mass spectrometry (TC‐EA/IRMS) and used to calculate the δ18O value of coffee bean water. The 18O enrichment of coffee bean water relative to the δ18O value of local precipitation was modeled as a function of local temperature and humidity. This function was incorporated into a mechanistic model of cellulose δ18O values to predict the δ18O values of coffee bean cellulose across coffee‐producing regions globally. Results The δ18O values of analyzed coffee bean cellulose ranged from approximately +22‰ to +42‰ (V‐SMOW). As expected, coffees grown in the same region tended to have similar isotope ratios, and the δ18O value of coffee bean cellulose was generally higher than the δ18O value of modeled stem cellulose for the region. Modeled δ18O values of coffee cellulose were within ±2.3‰ of the measured δ18O value of coffee cellulose. Conclusions The oxygen isotope ratio of coffee bean cellulose is a useful indicator of region‐of‐origin and varies predictably in response to climatic factors and precipitation isotope ratios. The isoscape of coffee bean cellulose δ18O values from this study provides a quantitative tool that can be applied to region‐of‐origin verification of roasted coffee at the point‐of‐sale.