Changes in Isoflavone Profile from Soybean Seeds during Cheonggukjang Fermentation Based on High-Resolution UPLC-DAD-QToF/MS: New Succinylated and Phosphorylated Conjugates

• Published in: Molecules (Basel, Switzerland) Vol. 27; no. 13; p. 4120
• Main Authors: Lee, Suji, Kwon, Ryeong Ha, Kim, Ju Hyung, Na, Hyemin, Lee, So-Jeong, Choi, Yu-Mi, Yoon, Hyemyeong, Kim, So Young, Kim, Yong-Suk, Lee, Sang Hoon, Yoo, Seon Mi, Kim, Heon-Woong, Wee, Chi-Do
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 27-06-2022; MDPI
• Subjects: Aglycones; Bioavailability; Biotransformation; cheonggukjang; Conjugates; Cultivars; Decarboxylation; Fermentation; Fermented food; Flavonoids; Food; Glucosides; Glucosides - metabolism; Glycine max - metabolism; isoflavone; Isoflavones; Isoflavones - metabolism; Microorganisms; NMR; Nuclear magnetic resonance; phosphorylated conjugates; Seeds; Seeds - metabolism; soybean seed; Soybeans; succinyl-glucosides; isoflavone; soybean seed; succinyl-glucosides; fermentation; UPLC-DAD-QToF/MS; phosphorylated conjugates; cheonggukjang
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules27134120

In this study, thirty-eight isoflavone derivatives were comprehensively identified and quantified from the raw, steamed and fermented seeds of four selected soybean cultivars based on UPLC-DAD-QToF/MS results with reference to the previously reported LC-MS library and flavonoid database, and summarized by acylated group including glucosides (Glu), malonyl-glucosides (Mal-Glu), acetyl-glucosides (Ac-Glu), succinyl-glucosides (Suc-Glu) and phosphorylated conjugates (Phos) in addition to aglycones. Among them, Suc-Glu and Phos derivatives were newly generated due to fermentation by
AFY-2 (
). In particular, Phos were characterized for the first time in fermented soy products using
species. From a proposed roadmap on isoflavone-based biotransformation, predominant Mal-Glu (77.5-84.2%, raw) decreased rapidly by decarboxylation and deesterification into Ac-Glu and Glu (3.5-8.1% and 50.0-72.2%) during steaming, respectively. As fermentation continued, the increased Glu were mainly succinylated and phosphorylated as well as gradually hydrolyzed into their corresponding aglycones. Thus, Suc-Glu and Phos (17.3-22.4% and 1.5-5.4%, 36 h) determined depending on cultivar type and incubation time, and can be considered as important biomarkers generated during
fermentation. Additionally, the changes of isoflavone profile can be used as a fundamental report in applied microbial science as well as bioavailability research from fermented soy foods.