Effects of blanching cultivation on the chemical composition and nutritional quality of Chinese chive.

Blanching is an agricultural practice where vegetables are cultivated in darkness to prevent photosynthesis, thereby modifying their colour, texture, and flavor. The technique is popularly employed in Chinese chive (CC). Blanched Chinese chive (BCC) is renowned for its pale-yellow appearance, delicate flavor, and culinary-medicinal values; nonetheless, how blanching alters the chemical composition largely remains intangible. In this study, the physiological, nutritional, and metabolic profiles of BCC and CC were investigated. In BCC, the contents of ascorbic acid, flavonoids, anthocyanins, etc. were decreased markedly, whereas the sugar content and pungency were increased significantly, indicating that blanching shaped the vegetable flavor. UPLC-ESI-MS/MS analysis revealed 366 differential metabolites between BCC and CC, and the metabolism of flavor precursors, S-alk(en)yl cysteine sulfoxides, were stimulated by blanching. Together, these findings give a strong clue that blanching increases the pungency flavor in CC, and is a useful technique for other selected vegetables.