Aroma Evolution during Flower Opening in Rosa damascena Mill

Abstract

The changes of aroma ingredients during the process of flower opening from Bulgarian rose were monitored by head space method and solvent extraction.W e also analyzed contents of glycosidic alcoholic aroma together with activities of the hydrolytic enzymes throughout the flower development and the opening. At flower petal opening time, the total amount of aromas in the head space gas reached the highest level. The concentration of citronellol was abundant in the head space gas at this stage, whereas the concentration o f 2-phenylethanol became higher than that of citronellol 4 hr after the opening stage. In the volatile extracts, higher accumulation was observed in 2-phenylethanol than those of monoterpenoids at this stage, and the content of the former still increased after flower opening. Glycosidic citronellol, geraniol, and other m onoterpenes started their accumulation ju st before flower opening stage and then reached the maximum level. The amount of these glycosidic compounds were less than those in the volatile extracts. In contrast to the monoterpenes, 2-phenylethyl glycosides accumulated in a higher level than in the volatile extracts starting at least 12 hr before the opening stage. The amount of the glycosidic precursors of 2-phenylethanol detected in the rose petals before flower opening always was higher than the amount of 2-phenylethanol which was released later. The decline of glycosidic 2-phenylethanol at flower opening stage may be due to partial enzymatic hydrol­ysis. Thereafter a drastic decline was observed, indicating that rapid enzymatic hydrolysis occurred during these stages.

Effect of Temperature on the Floral Scent Emission and Endogenous Volatile Profile ofPetunia axillaris

“…The ground powder was extracted twice with pentane (5 ml each) in a microwave oven (700 W) for 20 s in the presence of ethyl decanoate (20 mg) as an internal standard, as described previously. 8) The extract was dehydrated with anhydrous sodium sulfate and concentrated at 40 C in a water bath. 7) GC-MS and GC analyses.…”

Emission Mechanism of Floral Scent inPetunia axillaris

“…A constant stream of air (approx. 500 ml/min) filtered through activated charcoal 10) was piped through the bag, and volatile compounds were collected by Tenax-TA (150 mg) traps. The relative humidity in the Tedlar Bag was approx.…”

Characteristics of Floral Scent Compounds in a New Fragrant Petunia Cultivar TX-794 ‘Evening Scentsation’

“…Emitted volatile compounds were collected by the dynamic headspace method (Oka et al, 1999). Tedlar Bags (1L volume, GL Science, Tokyo, Japan) were placed over individual petunia flowers including the pedicels.…”