Dynamic changes in polyphenol compounds, antioxidant activity, and PAL gene expression in different tissues of buckwheat during germination

ABSTRACT BACKGROUND There is a growing interest in buckwheat germination regarding the improvement of its health benefits. The aims of this study were to evaluate the effects of germination on polyphenol compounds, antioxidant activity, and phenylalanine ammonia‐lyase (PAL) gene expression in different tissues (cotyledon, hypocotyl, and radicle) of buckwheat sprouts during germination for 12 days, as well as to investigate their interactions. RESULTS Total polyphenol and total flavonoid contents, antioxidant activity, main polyphenol components, and PAL gene expression significantly increased during germination. On day 12, the rutin content in cotyledons was elevated to 88.6 g kg−1, which was 7.7‐times and 39.4‐times compared to those in buckwheat seeds and radicles, respectively. Meanwhile, chlorogenic acid in hypocotyls reached 7.84 g kg−1, which was 36.3‐fold higher than those in radicles. However, the PAL gene showed the highest expression in radicles. CONCLUSION Present results showed that polyphenol compounds mainly accumulated in cotyledons and hypocotyls. There was a negative correlation between polyphenol compounds and PAL gene expression. The discrepancy suggested that polyphenol compounds might experience transportation within buckwheat sprouts. The study could provide useful information for further application of buckwheat in functional foods, and revelation of the correlation between bioactive components and related gene expressions. © 2018 Society of Chemical Industry