robusta adulteration of arabica (1)

16-O-methylcafestol (16-OMC)  is used as a marker for non-Arabica coffees (Robusta coffee). UK researchers have analysed lipophilic extracts from 30 authentic roasted Arabica coffees by high-field and low-field proton NMR spectroscopy, and found a small marker peak, which has subsequently been identified as 16-OMC and 16-O-methylkahweol.  This is the first time these markers have been found in Arabica coffee, and previously thought to only exist in non-Arabica coffee. However, the level of 16-OMC in Arabica coffee is very low and much higher in Robusta coffee. Therefore, using low-field NMR, Robusta in Arabica could be detected at levels of the order of 1–2% w/w. A surveillance study of retail purchased “100% Arabica” coffees found that 6 out of 60 samples displayed the marker signal to a degree commensurate with adulteration at levels of 3–30% w/w. 

Read the full article at: Arabica coffee authenticity

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