Pectic arabinans in quinoa seeds (Chenopodium quinoa Willd.) are acylated with p-coumaric acid

A modified digestion method was used to hydrolyze large amounts of quinoa meal to study polysaccharide-bound phenolic acids. Besides the well-characterized oligosaccharide O-(2-O-trans-feruloyl-α-L-arabinofuranosyl)-(1→5)-L-arabinofuranose, O-(2-O-trans-coumaroyl-α-L-arabinofuranosyl)-(1→5)-L-arabinofuranose was isolated from the hydrolysate and identified by LC-MS, GC-MS, and NMR experiments. This study demonstrates for the first time that p-coumaric acid can be linked to pectic side chains of dicotyledonous plants.