洛神花含有豐富的花青素、類黃酮、多酚類等生物活性成分，因而具備有抗發炎，維護肝臟健康的作用，甚至是養顏美容的功效。超臨界流體萃取技術(Supercritical fluid extraction, SFE)可以有效率的分離與純化食品藥材等天然植物中生物活性成分。本研究探討使用超臨界二氧化碳流體萃取法（Supercritical carbon dioxide, SC-CO2）及使用95℃熱水傳統方法與50 %乙醇萃取法,萃取洛神花中所含有的多酚(Polyphenols)，並比較三種萃取技術的優劣。實驗結果發現，乙醇及水溶液中多酚類萃取的能力比超臨界二氧化碳要來的高，其影響因素在於溫度還有極性的高低，而在超臨界二氧化碳萃取法中所提取出的雜質含量較少且種類簡單，故比較適合應用於多酚類的純化技術。利用添加乙醇於二氧化碳超臨界流體中當作共溶劑使用，使用此方法將可以萃取洛神花中所含有的高極性成分，藉此可以進一步探討二氧化碳超臨界流體萃取技術，與共溶劑乙醇流速和濃度萃取洛神花高極性成分之最適化條件。另外本研究還進一步測試不同溫度與壓力條件下二氧化碳超臨界流體萃取高極性成分之影響。實驗結果發現，洛神花中所含有的高極性成份萃取量隨著共溶劑的添加而增高，證明添加共溶劑乙醇，確實改變了二氧化碳超臨界流體的極性與溶解能力，因此提高了植物中所含有的高極性成分的萃取量。

Anthocyanins, flavonoids, polyphenols are rich in Roselle (Hibiscus sabdariffa L). New data and a meta-analysis of previous studies indicate that dietary Roselle can induce anti-inflammatory and maintain healthy liver function, and even can beautify the skin. Supercritical fluid extraction (SFE) has an efficient separation and purification of food ingredients, especially in the extraction of some active ingredients from natural plants. This study investigated the use of carbon dioxide supercritical carbon dioxide extraction parameters. SC-CO2 extraction, 95 ℃ water extraction, and 50% ethanol in water for extraction the polyphenols of roselle. Thus, we can compare the advantages and disadvantages between these three kinds of extraction methods. As the result shows, the composition of polyphenols in aqueous extractives and ethanol extractives are higher than supercritical carbon dioxide extractives, owing to their high potential factor, low temperature, and high polarity. Supercritical carbon dioxide is appropriate used to provide high purity and more selective extraction methodological development. Added the use of ethanol co-solvent in the supercritical
CO2 extraction of roselle high polar ingredients, to further explore the supercritical CO2 extraction technology, the total flow rate and concentration of extraction solvent ethanol Roselle optimal conditions for high-polar components, while this study further tests under different temperature and pressure conditions of supercritical CO2 extraction of polar components of high impact. Adding co-solvent was found after the
extraction of high polar component compared to no added co-solvent is also high,adding co-solvent proved to change the polarity of carbon dioxide is to increase the extraction of high polar components.