Publication no. C-2003-0416-07R |  VIEW ARTICLE

Levels of Avenanthramides and Activity of Hydroxycinnamoyl-CoA:Hydroxyanthranilate N-Hydroxycinnamoyl Transferase (HHT) in Steeped or Germinated Oat Samples.

Susanne Bryngelsson (1), Atsushi Ishihara (2), and Lena H. Dimberg (1,3). (1) Department of Food Science, Swedish University of Agricultural Sciences (SLU), P.O. Box 7051, SE-750 07 Uppsala, Sweden. (2) Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan. (3) Corresponding author. Phone: +46 (0)18 6710 00. Fax: +46 (0)18 672995. E-mail: <Lena.Dimberg@lmv.slu.se> Cereal Chem. 80(3):356-360. Accepted January 11, 2003. Copyright 2003 American Association of Cereal Chemists, Inc.

Concentrations of avenanthramides and activity of the biosynthetic enzyme hydroxycinnamoyl-CoA:hydroxyanthranilate N-hydroxycinnamoyl transferase (HHT) were analyzed in dry or, steeped nonmilled or milled, non-heat-treated (raw) or heat-treated oat samples (Avena sativa L.). Increased avenanthramide concentrations were found when intact raw groats were steeped. The increase was time- and temperature-dependent and maximal after 10 hr of steeping at 20°C. Continuous germination in air, after steeping, only contributed to a further increase in avenanthramides when steeping times were shorter than 10 hr. Concentrations of avenanthramides and HHT activity were positively correlated during steeping of intact groats at 8 and 20°C. The increase in avenanthramides was suggested to be due to de novo synthesis and a whole grain structure seemed to be required as no increase was found when groats were milled before steeping. Avenanthramide levels also increased when heat-treated samples, lacking HHT activity, were steeped. This increase may be due to release of bound forms, possibly formed during the preceding heat treatment.