DART-HRMS for the Rapid Assessment of Bioactive Compounds in Ultrasound-Processed Rapeseed Meal By-Product

In line with the recommended European policy for a zero-waste crop supply chain, a lab-pilot optimisation process to valorise the by-products of industrially produced rapeseed meal (RM) was performed. Three batches of RM were first processed into ethanol-wash solutes (EWS) and then optimised (OEWS) by an ultrasound-assisted (UA) treatment. After direct analysis in real time–high resolution mass spectrometry (DART-HRMS) analysis, data were processed applying a partial least square–discriminant analysis (PLS-DA), which retrieved the 15 most discriminative ions able to characterise the biochemical changes during the ethanol-washing and UA optimisation process. The metabolomic fingerprinting of EWS and OEWS generated an accurate and well-defined 3D spatial clusterisation based on a restricted pool of informative bioactive compounds. A significantly higher relative abundance of sinapic, azelaic, and vernolic acids and a lower incidence of the oleic and palmitic fatty acids were detected in OEWS. DART-HRMS generated a vast amount of biochemical information in one single run, also demonstrating that its association with an untargeted multivariate statistical approach would be a valuable tool for revealing specific functional biomarkers. This would eventually enhance the circular and effective use of rapeseed residuals coming from this plant’s oilseed industry.