PHENOLIC BIOSYNTHESIS DURING GRAIN DEVELOPMENT IN WHEAT (TRITICUM-AESTIVUM L) .3. CHANGES IN HYDROXYCINNAMIC ACIDS DURING GRAIN DEVELOPMENT

Changes in bound and soluble hydroxycinnamic acids have been investigated during the development of wheat grain. Analysis by HPLC revealed that the level of trans-ferulic acid decreased in the soluble fraction but the bound fraction increased steadily during grain development. The concentration of the cis-isomer was from 0·5–4 % of the trans-isomer. Changes in soluble trans-p-coumaric and trans-sinapic acids followed a similar pattern whereas the level of bound trans-p-coumaric acid peaked near ripeness. These results suggest that there is considerable metabolic turnover of hydroxycinnamic acids during grain development; these changes could affect the properties of both the cell wall and the whole grain. Comparison of red and white cultivars revealed significant differences in the ferulic acid content per grain 20 days after ear emergence but little difference at maturity. © 1991, Academic Press Limited. All rights reserved.