| Summary: | 碩士 === 國立臺灣海洋大學 === 食品科學系 === 102 === Recently, Chlorella are attracting enormous attention, and the studies about biological activities have been discussed, including antioxidant, anti-diabetes, anti-hypertension, anti-cancer, anti-microbial, lipid metabolic regulation and hepatotective activities. Since phenolic acids have similar bioactivities, this study would analyze the phenolic acids contents of Chlorella sorokiniana, study the optimum conditions of extraction, and evaluate the effect of cell disruption methods.
Different factors that influence the phenolic acids extraction procedure such as solvent composition, organic solvent liquid-liquid extraction (LLE) process were optimized. In addition, three extraction systems: conventional orbital shake extraction (CSE), ultrasonic-assisted extraction at room (UAE-RT), and ultrasonic-assisted extraction at degrees Celsius (UAE-60℃) were studied. By comparing the extraction yields and phenlic acids contents, the most efficient method is UAE-60℃ with 70% aqueous methanol solution, ratio of sample to solvent is 1:20 (g/mL). Ultrasonic extract for 30 min, three times. After acidified the extracts, the aquesous solution of the extracts were partitioned with with hexane, ether/ethyl acetate (1/1, v/v) liquid-liquid extraction. After that, alkaline hydrolyzed aquesous layer for 4 hrs, acidified and LLE with hexane, ether/ethyl acetate again.
Analysis of Chlorella sorokiniana phenolic acids fractions has been carried out by high-performance liquid chromatography (HPLC). Diverse phenolic acids, namely chlorogenic acid, caffeic acid, p-comaric acid, and ferulic acid were detected in the analysed extract. The analysis conditions used Inertstil C4 column (5 um, 4.6 #westeur024# 250 mm), modified the ratio of mobile phase to methanol/water = 32/68 (v/v) with phosphoric acid 0.04% (v/v, pH 2.6), and injected 20 L, at room temperature, and detected with 280, 310, 320 nm. Retention times are 8.65 min (chlorogenic acid), 12.94 min (caffeic aci), 23.33 min (p-comaric acid) and 26.74 min (ferulic acid).
To investigate the relation between phenolic acids contents and cell disruption methods, Chlorella sorokiniana divided into three groups, unpulverized, physical pulverized and enzymatic hydrolyzed. The statistical results showed that different cell disruption treatments would affect phenolic acids contents. Enzymatic hydrolysis group contains highest phenolic acids contents: chlorogenic acid 1213.67 ± 8.38 (ug/g), caffeic acid 1118.95 ± 6.73 (ug/g), p-coumaric acid 86.79 ± 5.43 (ug/g) and ferulic acid 42.10 ± 0.90 (ug/g), that would be the optimum cell disruption method.
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