Evaluation of glycerophospholipid content in vegetables processed with different cooking methods using high-performance liquid chromatography-evaporative light scattering detector

Glycerophospholipids, also known as phospholipids, are polar lipids with a structure composed of one polar phosphate group and two nonpolar fatty acids attached to glycerol. Phospholipids possess emulsifying capabilities, and choline-derived phospholipids specifically play a crucial nutritional role in the growth of newborns, brain development, and the formation of nervous tissue. In this study, we established an HPLC-ELSD analysis method for the quantitative analysis of phospholipids present in various vegetables processed with different cooking methods (raw, grilled, blanched, steamed, and stir-fried). For method validation, we measured the linearity of the calibration curve, detection limit, and quantification limit. The in-house quality control material, infant formula, was analyzed to verify the accuracy and precision of the analysis results. Phospholipids (PC, phosphatidylcholine; PE, phosphatidylethanolamine; PS, phosphatidylserine; PI, phosphatidylinositol; LPC, lysophosphatidylcholine; SM, sphingomyelin) from vegetable foods were extracted using the folch method. Among the vegetables, there was a relatively higher content of total phospholipids in eggplant (30.887-588.619 mg/100 g) and spinach (150.780-460.265 mg/100 g). Generally, the total phospholipid content tended to increase after cooking compared to the raw vegetables. Specifically, in the case of eggplant, the total phospholipid content increased from 30.887 mg/100g in the raw state to 496.432-588.619 mg/100g after cooking (grilled, boiled, and steamed) with PC and PE predominantly detected. This study provides information on the phospholipid content in food ingredients and investigates the changes in functional phospholipids based on cooking methods.