| Summary: | 碩士 === 國立中興大學 === 化學工程學系所 === 104 === Lutein is an important component of health food for protecting the eyes. However, its applications in actual health supplements are rather limited as the substance is a fat soluble nutrient and has very low water solubility. This study aimed to develop a form of lutein ester with improved water solubility to enhance its applications in health supplements. Raw materials provided by the supplier first underwent ultrasonic stirring to extract lutein ester using hexane, acetone, and tetrahydrofuran (THF) at a solvent-to-solid ratio (SSR) of 80 with an extraction time of 60 minutes. Results found that the THF extract provided 25.3% of lutein. The THF extract was then subject to liquid-liquid extraction using a methanol / hexane (1:1, v/v) solvent to further raise lutein purity to 44.7%. However, the solubility of hexane-extract in water was still very close to zero. β-cyclodextrin (β-CD) was then added to the purified material in the supercritical carbon dioxide antisolvent (SAS) process to generate an encapsulated lutein ester with improved water solubility. The process was carried out under a fixed temperature of 55ºC, time of 10 min, and feed flow rate of 0.5 mL/min. Total yield (TY) of the encapsulated material, lutein ester concentration (Clut), encapsulation efficiency (EE), recovery (R), and dissolution rate (RD) were investigated under different emulsifiers (Tween 20 and Tween 80), emulsifier concentrations (15 % and 25 %), stirring times (0.5, 2, 4, and 6 hr), pressures (120 and 140 bar), and feed ratios of the extracted material and β-cyclodextrin (Wext/Wβ-CD) (0.5, 1, and 2). Results showed that the experimental conditions of 25 % of Tween 80 as emulsifier, 4-hr stirring time, 140 bar, and Wext/Wβ-CD of 0.5 gave better results of 77.9% EE, 43.6% R, 30.6% DR, 69.0% TY, and 94.1 mg/g Clut. A response surface methodology (RSM) experiment with central composite design (CCD) was then employed using the aforementioned conditions to identify the optimal SAS temperature (45, 55, and 65ºC) and emulsifier concentration (15, 25, and 35 %). Results of the RSM experiment predicted an optimal condition of 58oC for the temperature and emulsifier concentration of 33.6 %, which would provide the following: 68.8% EE, 43.3% R, 31.0% DR,71.7% TY, and 89.2 mg/g Clut. Using SAS for β-CD with emulsifier encapsulation of extracts rich in lutein ester would help improve dissolution rate in water about 31%. Water solubility was significantly increased for the encapsulated product, improving the applicability of lutein ester in health foods.
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