Phytochemical composition and variability in Quercus ilex acorn morphotypes as determined by NIRS and MS-based approaches.

Quercus acorns have been used as a staple food since archeological times; currently, there is a renewed interest in the direct use of the acorns as nuts or as a source of consumable flour. In this regard, the phytochemical composition and variability of various morphotypes of acorns from Quercus ilex have been determined by using two platforms, near infrared spectroscopy (NIRS) and mass spectrometry (MS)-based metabolomics. According to NIRS, starch was the most abundant compound (50-60%). UHPLC-QToF analysis was used for untargeted metabolomic analysis and 192 metabolites were annotated. Principal component analysis (PCA) discriminated the morphotypes; 50 compounds out of 192 identified had the highest load over the first two PCA components (explaining 67.2% variability) and can be potential markers of variability. The data presented here support the value of acorns as a source of nutritionally rich compounds thus justifying their use a good alternative to other nuts.