Measuring Flavonoid Enzyme Activities in Tissues of Fruit Species

• Published in: Journal of agricultural and food chemistry Vol. 57; no. 11; pp. 4983 - 4987
• Main Authors: Halbwirth, Heidi, Waldner, Ines, Miosic, Silvija, Ibanez, Mireia, Costa, Guglielmo, Stich, Karl
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 10.06.2009
• Subjects: Biological and medical sciences; Flavonoids - metabolism; Food Chemistry/Biochemistry; Food industries; Fruit - chemistry; Fruit - enzymology; Fruit - metabolism; Fruit and vegetable industries; Fundamental and applied biological sciences. Psychology; Plant Proteins - analysis; Plant Proteins - genetics; Plant Proteins - metabolism; Substrate Specificity; gooseberry (Ribes uva-crispa); raspberry (Rubus x ideaus); enzyme preparation; Blackberry (Rubus fruticosa); elder (Sambucus x nigra); polyphenol (tannin) rich tissue; flavonoid biosynthesis; cherry (Prunus avium); plum (Prunus domestica); sour cherry (Prunus cerasus); kiwi fruit (Actinidia deliciosa); Fruit; Enzyme; Flavonoid; Tissue; Polyphenol; Species
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf900121z

Flavonoids are important secondary metabolites, which are ubiquitously present in plant-derived food. Since flavonoids may show beneficial effects on human health, there is increasing interest in the availability of plants with a tailor-made flavonoid spectrum. Determination of flavonoid enzyme activities and investigations into their substrate specificity are an important precondition for both classical and molecular approaches. We tested two different protocols for enzyme preparation from eight fruit species. In many cases, a protocol adapted for polyphenol-rich tissues was superior. Using a suitable protocol for investigations of kiwi fruits, we show that flavanone 3-hydroxylase is absent in the green-fleshed cultivar Hayward. As flavonoid enzyme activities could be detected in harvested kiwi fruits over a storage period of five months, postharvest modification of the flavonoid spectrum has to be expected.