Study on the dynamic changes of hydroxycinnamic acid derivatives during wort saccharification process
Hydroxycinnamic acids(HCA),represented by ferulic acid,are important antioxidant substances and flavor precursors in beer.In order to explore the dynamic changes of HCA compounds during the wort saccharification process,this study evaluated the content and antioxidant capacity of polyphenols in wort at different stages of saccharification by means of Folin-Ciocalteu method,DPPH free radi-cal and ABTS cation free radical scavenging assays.The results showed that the trend of polyphenol content in wort during saccharification process was consistent with its antioxidant capacity,which both gradually increased and then stabilized.By employing ultra-high perform-ance liquid chromatography-quadrupole-time-of-flight mass spectrometry(UPLC-Q-TOF MS)combined with global natural products social(GNPS)molecular networking,the changes of composition and content at different stages of wort saccharification were further analyzed.GNPS molecular networking facilitated the accurate identification of 87 compounds including HCAs,such as ferulic acid(1),caffeic acid(2),p-coumaric acid(3),sinapinic acid(4),as well as other 27 HCA derivatives.The analysis also revealed diverse dynamic changes of different HCA derivatives during wort saccharification,most of which show an initial increase followed by a decrease.Compound 34(C7H5NO2)exhibited a continuous increase throughout the saccharification process and may be served as a marker for decomposition of HCAs during saccharification.These findings provide valuable guidance for optimizing the saccharification process to produce high-quality beers.