Figure 2
From: Niacin, alkaloids and (poly)phenolic compounds in the most widespread Italian capsule-brewed coffees
Capsule variability of caffeine (A), trigonelline (B), N-methylpyridinium (C) and total caffeoylquinic acids (D) of capsule espresso coffee samples. Capsules were representative of regular, lungo, and decaffeinated coffees belonging to the five considered brands. CQAs, caffeolylquinic acids; EC, espresso coffee; NMP, N-methylpyridinium.
