1. Plant Molecular Science Group, Bower Building, Division of Biochemistry and Molecular Biology, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, U.K., Department of Human Nutrition, University of Glasgow, Queen Elizabeth Building, Royal Infirmary, Glasgow G31 2ER, U.K., and Safeway plc, Beers, Wines, Spirits and Tobacco Unit, 6 Millington Road, Hayes, Middlesex UB3 4AY, U.K.