Making of rose liqueur

Roses belong to Rosa genera of the Rosaceae family. They are colorful, beautiful and fragrant. We usually call them queens in flowers. The main use of domestic rose is cut flower. However, due to the perishable and fragile characteristics of rose flowers, we need to develop a new product to maximize the profits. The purposes of this thesis are (1) qualitative and quantitative analysis of the anthocyanins of Grand Gala rose grown in Taiwan, also to identify flavor impact compounds of rose liqueur and the changes during soaking, (2) to understand the composition of rose liqueur and color change during soaking and storage, and to establish the process for rose liqueur manufacture, and (3) to investigate the effect of different phenolic compounds on quality during product storage.
The result shows that anthocyanin content of Grand Gala is 5-10 mg/g fwt, and the major species of anthocyanin is Cyanidin-3,5-diglucosides. The major volatile compounds of Double Delight liqueur are alcohols including benzeneethanol, 3-methyl-1-butanol, etc.
Rose petals of Grand Gala cultivar were washed, chopped or not, and then soaked at 1.5:10 w/v ratio in 30 % formulated ethanol solution at 25 oC. Nearly all anthocyanins in both of the samples with and without chopping treatment were extracted in one and two days, respectively. The sample with chopping treatment browned more seriously. Therefore, chopping was not applied in the subsequent experiments.
In soaking of the petals at various solid-liquid ratio (1:10, 1.5:10, and 2:10) in ethanol solutions at various concentrations at 25 oC, extraction of anthocyanins were nearly completed within 2 days in all the samples. A higher solid-liquid ratio favors the effectiveness of anthocyanin extraction, and the effect of ethanol concentration on anthocyanin extraction is not significant difference.
The rose liqueur was membrane filtrated and formulated to 16 % ethanol, 20 oBrix, and 1 % acidity for sensory evaluation. The appearance of our samples was superior to commercial products, whereas the aroma was inferior. Rose liqueur of Double Delight cultivar was prepared to blend with that of Grand Gala cultivar. The blended samples were found to be superior to commercial products in appearance and overall acceptance. At blending ratio 1:9 (Double Delight liqueur/Grand Gala liqueur, v:v), the sample has a higher antioxidative activity as well.
After 3 months storage, our result showed that (1) color a value of rose liqueur with sucrose treatment had a slower decreased than with fructose treatment, (2) the sample added with caffeic acid or ferulic acid or tea polyphenol showed no significant difference in the color, anthocyanins content, and antioxidant capacity during storage as compared to control, and (3) the total amount of volatile compounds of rose liqueur decreased gradually, however there was one ester volatile formed, hexadecanoic ethyl ester, during storage.