Faculty of Agriculture, University of South Bohemia, Studentská 13, České Budějovice 370 05, Czech Republic.
Laboratory of Metabolomics and Isotopic Analyses, Global Change Research Institute, CAS, Bělidla 986/4a, 603 00 Brno, Czech Republic.
Food Chem. 2018 Aug 30;258:314-320. doi: 10.1016/j.foodchem.2018.03.090. Epub 2018 Mar 21.
Tartary buckwheat achenes are rich in rutin. However, its utilisation as a food is low due to the bitter taste of the products because of the transformation of rutin to quercetin. The aim of this study was to determine the stability of rutin and selected flavonoids, which are influenced by the different sample preparations exposing the achenes to higher temperatures (60 °C, 100 °C, and 140 °C), and also to determine the specificity of the rutin degrading enzymes in Tartary buckwheat. The achenes were directly extracted with methanol pre-extracted with hexane, or lyophilised before extraction. The rutin and quercetin contents were determined by HPLC. The rutin-degrading enzymes in Tartary buckwheat achenes were not inactivated after a heat treatment up to 140 °C acting on them for three hours; neither to lyophilisation nor pre-extraction with hexane. The rutin-degrading enzymes probably caused the deglycosylation of kaempferol-3-O-rutinoside, kaempferol-3-O-β-d-glucoside and piceid. Rutin-degrading enzymes were inactivated with 100% methanol.
鞑靼荞麦的种皮富含芦丁。然而，由于产品的苦味，其作为食品的利用率很低，这是由于芦丁向槲皮素的转化。本研究的目的是确定芦丁和选定的类黄酮的稳定性，这些稳定性受到不同样品制备的影响，这些制备将种皮暴露于更高的温度（60°C、100°C 和 140°C）下，并确定鞑靼荞麦中芦丁降解酶的特异性。种皮先用正己烷进行预提取，然后用甲醇直接提取、冻干提取。采用 HPLC 法测定芦丁和槲皮素的含量。鞑靼荞麦种皮中的芦丁降解酶在 140°C 下热处理 3 小时后并未失活；也不会因冻干或用正己烷预提取而失活。芦丁降解酶可能导致圣草酚-3-O-芦丁苷、圣草酚-3-O-β-d-葡萄糖苷和落新妇苷的去糖基化。芦丁降解酶可被 100%甲醇失活。
