碩士 / 國立臺灣大學 / 農業化學研究所 / 87 / The subject of this study is to investigate an efficient method for preparing high EPA/DHA content products from squid visceral oil as well as a method to remove cholesterol efficiently. We also study the storage stability of these high EPA/DHA content products and their glyceride derivatives.
Firstly, we studied the suitable conditions for the hydrolysis of squid visceral oil to prepare the corresponded free fatty acids. It revealed that complete hydrolysis of the squid visceral oil could be carried out by saponification with NaOH at an amount of 1.2 times equivalent of the saponification value of the raw material in methanol, 95% ethanol or acetone. The acid value of hydrolysis product was around 178 mg KOH/ g oil. Besides, we also found that the same result could be obtained when saponification was carried out in 10 volumes of acetone at room temperature for 24 hours. We could obtain the high EPA/DHA product when it was neutralized with NaOH at an amount of 0.8 equivalent acid value in 5 volumes of acetone at room temperature for 1 hour. The content of EPA/DHA was 67.4% in the oil obtained from the supernatant. The precipitate was adjusted with hydrochloric acid and repeated the extractions twice as described above. The EPA/DHA content and recovery of the combined final materials was 57.2% and 90.9%, respectively.
In additions, when the precipitate of saponification in acetone was extracted by acetone twice, the EPA/DHA contents of the supernatant and the two extracts (30 minutes) were 53.3%, 65.1%, and 45.1%, respectively. The recoveries were 36.0%, 13.2%, and 3.1%, respectively. The total recovery of EPA/DHA was 52.3%. The EPA/DHA content of the supernatant and two extracts (24 hours) were 72.0%, 62.8%, and 58.3%, respectively. The recoveries were 45.0%, 9.1%, and 3.9%, respectively. The total recovery of EPA/DHA was 58.0%.
On the other hand, we found that the cholesterol in the hydrolysis products of squid visceral oil could be efficiently removed by flush silica gel column chromatography using n-hexane as the solvent. This method could remove 83.0% cholesterol from the hydrolysis products of squid visceral oil. And add cholesterol to raw squid visceral oil to cholesterol content was 1.0%, This method could dislodge 97.8% cholesterol from raw squid visceral oil.
In this study, we also enzymatically converted the high EPA/DHA hydrolysis products to the glyceride derivatives, and compared their storage stabilities. We found that both Products were very stable, and the EPA/DHA contents decreased only slightly from 67.4% to 65.6% at 60℃after 10 days. Besides, we found that the natural antioxidants including Vit. E, ascorbyl palmitate, tea antioxidant and rosemary could significantly improve the storage stability of these high EPA/DHA p
| Identifer | oai:union.ndltd.org:TW/087NTU00406036 |
| Date | January 1999 |
| Creators | Chen, Yu -Ling, 陳玉鈴 |
| Contributors | Lee, Min-Hsiung, 李敏雄 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 81 |
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