Revealing the Structure Types of Glycosylated Quercetins and Their Derivatives From Rutin Under High‐Temperature Processing by LC‐ESI‐MS/MS

It has been well established that a high dietary intake of rutin is associated with a reduced risk of chronic diseases. Rutin-rich edible parts of natural plants are often prepared into various functional foods. However, a decrease in rutin content is generally observed in the end products, with high-temperature processing identified as one of the main causes. Therefore, the use of lower temperatures during food preparation is often suggested. Quercetin, the sugar-removed product of rutin, has previously been reported as the only degradation product of rutin. In this study, however, an additional 57 previously unreported structural types of glycosylated quercetins and their derivatives were identified as rutin degradation products after treatment at 180°C for 20 min using HPLC-ESI-MS/MS. About 24 ± 1.41% (mol) of rutin was transformed into these degradation products. Notably, the retained rutin in the heated sample exhibited an unexpectedly high apparent solubility of 7.0 ± 0.3 mg/mL, which is 46.7 times greater than rutin intrinsic solubility, suggesting improved bioavailability of poorly soluble rutin. It is speculated that the enhanced apparent solubility is due to the formation of polysaccharide-modified quercetin and its derivatives. This study provides valuable insights for comprehensively evaluating the effects of high-temperature processing on the preparation of functional foods containing rutin.