A bioassay based on an olfactory conditioning method simulating the foraging situation in laboratory conditions was coupled with chemical analysis of volatile sunflower blends. Behavioural data obtained from for-agers'responses to volatile fraction point out that honeybees need to use only a limited fraction acting as a "simplified aromatic pattern" of the plant, among hundreds of compounds constituting the whole aroma. This active fraction included 27 polar compounds among which 14 were identified. Extension of such data to crop pollination and plant improvement is discussed.
The phenolic compounds of the ethyl acetate extractable fraction of bilberry juice-Vaccinium myrfillus-were separated and collected by semi-preparative HPLC. Three flavonoids [quercetin-3-rhamnoside (quercitrin), quercetin-3-galactoside (hypersoide), quercetin-3-glucoside (isoquercitrin)], six phenolic acids [caffeic, chlorogenic, paracoumaric, ferulic, syringic, hydroxybenzoic derivative] previously reported, and other phenolic acids [gallic, protocatechic, p-hydroxybenzoic, m-hydroxybenzoic, vanillic, m-coumaric, o-coumaric] were detected by analytical RP-HPLC, TLC procedures, acid and alkaline hydrolyses and spectral characteristics examination. Some of these compounds have not yet been reported for bilbenies. The absence of flavan-3-01s and their weakly condensed derivatives, which have already been identified in this fruit, would be attributed to the maturity stages of bilberries and to the strong reactivity of monomeric and dimeric flavan-3-01s.
Rapid and direct methods for the determination of the coloring pigments were applied to fresh and fermented bilberry juices--Vuccinium myrtilfius-as well as to their fractionation products isolated by preparative column chromatography. These methods were: bisulfite decolorization, chromatic indices and analytical column chromatography for the appreciation of the different pigment states. Results obtained from these experiments gave an estimation and comparison of the states and the forms of the coloring pigments and underlined the effects of the physicochemical treatments such as condensation or degradation of pigments during fermentation, preservation and experimental procedures.
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