**3. Results**

This study summarizes the occurrence of furfuryl alcohol and β-myrcene in various foods and beverages. Limited studies on β-myrcene (7) were observed compared to 19 studies for furfuryl alcohol. Meta-analysis was not possible due to the sparsity of studies for each type of food and beverage. The occurrence of furfuryl alcohol was recorded in many foods and beverages that had been subjected to thermal processing. The literature studies summarized in Table 1 were extended by inclusion of original results from our own analyses on furfuryl alcohol in 30 coffee, 15 bread, 20 wine, and 50 aged alcoholic spirit samples. From these, only coffee samples were positive (average furfuryl alcohol content of 251 mg/kg), while all other samples were below the detection limit of the method. A typical spectrum of a coffee sample is shown in Figure 1.

Out of the seven studies on β-myrcene, four were in hops and related products, while two were in beer, and the final reference reported about general use levels in various foods/beverages. Chewing gum, gelatin, beer, and hops were suggested as products with high concentration of β-myrcene. The studies are summarized in Table 2.


**Table 1.** Furfuryl alcohol content in various foods and beverages.

a The ambiguous unit ppm was interpreted as mg/L for liquids/beverages and as mg/kg for solid foods. b All samples evaluated (spirits types whiskey, rum, brandy as well as various wines and breads) were below the limit of detection (LOD; 3.2 mg/L). c Studies from the same research group with probably overlapping data. d Number of samples not provided. The data are suggested as being "usual concentrations" found in these food/beverage types.

**Figure 1.** NMR spectra of an authentic coffee sample (**blue line**) containing 408 mg/kg of furfuryl alcohol compared to the reference standard (**red line**).


**Table 2.** β-Myrcene content in various matrices.

a The ambiguous unit ppm was interpreted as mg/L for liquids/beverages and as mg/kg for solid food. b Number of samples not provided. The data are suggested as being "usual concentrations" found in these food/beverage types.
