乾燥玫瑰花茶製程之改進

Abstract

本研究選用佳娜紅品種玫瑰花及雙喜品種玫瑰花為材料，進行以下實驗：（1）模擬傳統部分發酵茶之加工方式，探討最佳條件，並建立佳娜紅玫瑰部分發酵花茶較適加工製程。成品再與經由不同溫度之熱風乾燥佳娜紅玫瑰花瓣成品進行感官品評，以確立乾燥佳娜紅玫瑰花茶之較適製程；（2）利用薰花技術，先將佳娜紅玫瑰花瓣與雙喜玫瑰花瓣共置後，再分別進行乾燥加工，最後以不同比例進行調配，以確立最佳混合玫瑰花茶製程；（3）利用不同浸漬液及浸漬方式針對佳娜紅玫瑰花瓣進行加工，探討乾燥玫瑰花在不同條件之貯藏期間花青素之變化量。 結果顯示佳娜紅玫瑰部分發酵花茶較適製程為佳娜紅玫瑰花瓣以48 ℃熱風萎凋30分鐘及室內萎凋12小時，經250 ℃炒菁5分鐘，再以70 ℃乾燥6小時。惟以此製程製得之產品與以不同溫度之熱風乾燥法所得者相較，發現在整體喜好性皆無顯著差異（p<0.05），顯示部分發酵處理無法有效地提高茶湯風味。混合玫瑰花茶較適調配比例實驗結果則顯示，佳娜紅玫瑰花瓣與雙喜玫瑰花瓣以5：1比例混合者，具有較佳之顏色及香氣。 貯藏實驗結果顯示，pH值、溫度、光線及氧氣確實為影響花青素穩定性之因子。新鮮玫瑰花瓣利用1 M檸檬酸溶液真空浸漬後乾燥，於不同條件下貯藏3個月後，其花青素保留量仍顯著高於其他處理組，顯示此加工方式對於乾燥玫瑰花茶之花青素含量及外觀保持具有助益。

Both Grand Gala and Double Delight roses were used as the materials in this study. The aim of this study were (1) to mimic the traditional processing of partial fermented tea to establish the optimum process for partial fermented dried Grand Gala roses tea. The sensory evaluation was performed to compare the quality between partial fermented and hot-air dried Grand Gala roses to establish the optimum process of dried Grand Gala rose tea; (2) to mix together with dried Grand Gala and Double Delight roses at various ratio, dried individually, and then evaluated the blend ratio of dried roses to find out the optimum process of mixed rose tea; (3) to investigate the change of total anthocyanins content in dried Grand Gala rose petals during storage priors processed by various immersion solutions and pressures. Results show that the optimum processing of partial fermented Grand Gala rose tea is: rose pellets undergo hot-air withering at 48 ℃ for 30 minutes follows indoor withering at 27 ℃ for 12 hours, then panning at 250 ℃ for 5 minutes, finally, hot-air drying at 70 ℃ for 6 hours. However, the results of sensory evaluation showed there have no significant difference between rose infusions make from partial fermented and hot-air dried Grand Gala roses tea. In the making of mixed rose tea, sensory results show that dried Grand Gala rose and Double Delight rose petals mixed at 5:1 w/w ratio were obtain rose tea with good color and aroma. The results of storage test show that the stability of anthocyanins in rose petals is influenced by pH of solution, storage temperature, light and oxygen. The anthocyanin content of dried Grand Gala rose petals priors vacuum immersed with 1 M citric acid solution is significantly higher then other products over three months, indicate that this treatment is useful to maintain the content of anthocyanins and the appearance of dried rose tea.