Testing the effects of drying methods on willow flavonoids, tannins, and salicylates

Citation
R. Julkunen-tiitto et S. Sorsa, Testing the effects of drying methods on willow flavonoids, tannins, and salicylates, J CHEM ECOL, 27(4), 2001, pp. 779-789
Citations number
26
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Environment/Ecology
Journal title
JOURNAL OF CHEMICAL ECOLOGY
ISSN journal
0098-0331 → ACNP
Volume
27
Issue
4
Year of publication
2001
Pages
779 - 789
Database
ISI
SICI code
0098-0331(200104)27:4<779:TTEODM>2.0.ZU;2-0
Abstract
In this study, we compared the effects of several preservation methods on t he secondary phenolics of the mature leaves of purple willow (Salix purpure a L., Salicaceae) with results obtained with fresh leaf analyses. Conventio nal freeze-drying, in which the leaves were first frozen with liquid nitrog en and then placed in a freeze-dryer, produced substantial qualitative and quantitative changes in purple willow flavonoids and salicylates. Modified freeze-drying, in which leaves were put into a freeze-dryer without being p refrozen, gave concentrations that, for most secondary components, were com parable with those found in fresh leaves. Reducing the freeze-dryer chamber temperature hindered the decomposition of phenolics in prefrozen leaves an d in leaves dried without prefreezing. Heat drying induced substantial chan ges in the composition of all phenolics, except for apigenin-7-glucoside. V acuum drying at room temperature gave the highest concentrations for nearly all phenolics, while room-drying with desiccation gave results that were c omparable with those obtained by fresh leaf analyses.