Enzymatic Browning in Sugar Beet Leaves (Beta vulgaris L.): Influence of Caffeic Acid Derivatives, Oxidative Coupling, and Coupled Oxidation.

ABSTRACT: Sugar beet (Beta vulgaris L.) leaves of 8 month (8_m) plants showed more enzymatic browning than those of 3 month (3_m). Total phenolic content increased from 4.6 to 9.4 mg/g FW in 3_m and 8_m, respectively, quantitated by reverse-phase-ultrahigh-performance liquid chromatography-ultraviolet-mass spectrometry (RP-UHPLC-UV-MS). The PPO activity was 6.7 times higher in extracts from 8_m than from 3_m leaves. Substrate content increased from 0.53 to 2.45 mg/g FW in 3_m and 8_m, respectively, of which caffeic acid glycosyl esters were most important, increasing 10-fold with age. Caffeic acid glycosides and vitexin derivatives were no substrates. In 3_m and 8_m, nonsubstrate-to-substrate ratios w

SUBMITTER: Vissers A 

PROVIDER: S-EPMC5481818 | biostudies-literature | 2017 Jun

REPOSITORIES: biostudies-literature