Comparative Degumming of Rapeseed Oil: Phospholipid Recovery, Bioactive Lipid Concentrations, and Molecular Remodeling

Rapeseed oil is an important edible oil with a favorable fatty acid composition and contains endogenous phospholipids (PLs) and lipid-soluble minor components that are relevant to refining, oxidative stability, and product quality. In this study, water degumming (WDG), citric acid degumming (ADG), and ethanol degumming (EDG) were systematically evaluated for their effects on oil quality, phospholipid recovery, and bioactive lipid concentrations. A modified Folch extraction was included solely as a laboratory solvent-extraction benchmark for the compositional characterization of phospholipid-rich fractions. WDG and ADG showed the highest phosphorus removal efficiency, reducing phosphorus to undetectable levels, whereas EDG also achieved substantial dephosphorization. ADG produced the highest PL yield (83.22%), while WDG gave the highest oil recovery (98.42%) and PL purity (95.49%). Although the bulk FA composition of the oil remained largely unchanged after treatment, the recovered PL fractions showed clear differences in FA distribution and PL subclass composition. EDG yielded the highest phosphatidylcholine (PC) and lysophosphatidylcholine (LPC) contents, indicating selective enrichment of choline-containing PLs. The concentrations of carotenoids, tocopherols, and phytosterols were also process-dependent. Untargeted metabolomic and lipidomic analyses further showed that EDG induced distinct compositional remodeling relative to crude rapeseed oil. Overall, WDG was preferable for oil retention, ADG for maximum PL recovery, and EDG provided a distinct balance between oil recovery, PL recovery, and enrichment of PC- and LPC-containing fractions.