碩士 / 國立臺灣大學 / 食品科技研究所 / 89 / Polyunsaturated fatty acids (PUFA) are confirmed to have various beneficial physiological functions. The most abundant edible source is fish oil. Extraction and purification of the lipids by conventional methods, such as n-hexane extraction or vacuum distillation, presents some problems due to oxidation of the PUFA. The possibility of both operating at relatively low temperature and preventing oxidation has made SC-CO2 a very popular separation process.
The purpose of this study was both to get an edible refined fish oil and turn the waste to become a value-added product. The experimental material was wet-rendered mackerel oil (crude oil). It was separated from the waste water which was generated from canned and steam-cooked mackerel meat. Crude oil was treated with various conditions of SC-CO2. Both extracted and residual oils after various volume of SC-CO2 extraction were analyzed to determine the optimum condition. The oxidative stability of SC-CO2 refined oil was compared to both crude oil and chemically refined oil (alkali refining, degumming and bleaching).
The acid value (AV), phospholipid content, Lovibond color, hedonic grade (the higher the better) and peroxide value (POV) of crude oil was 0.39 (mg KOH/g oil), 7.42 (mg/g oil), 3.1Y, 1.5R, 2.52±0.87 and 2.0 (meq/kg oil), respectively, and of residual oil after 800 NL SC-CO2 extraction was 0.14 (mg KOH/g oil), 17.0 (mg/g oil), 4.4Y, 1.0R, 3.76±1.30 and 4.0 (meq/kg oil), respectively. The DHA content of 800NL CO2 residual oil was slightly higher than crude oil. The unsaponifiable matter of 800NL CO2 residual oil was greatly lower than crude oil. The AV raising rate of 800NL CO2 residual oil was much higher than crude oil and extracted oil during six month-storage at 4oC.
The 800NL CO2 greatly removed free fatty acids and malodor substances but left gum and color. Therefore, the extracted oil after 1200NL SC-CO2 extraction was used for the second step 300 NL SC-CO2 extraction. The residual was what we called SC-CO2 refined oil. Its AV, phospholipid content, Lovibond color and hedonic grade was 0.21 (mg KOH/g oil), 5.03 (mg/g oil), 1.1Y, 0.4R and 4.10±1.14, respectively. The oxidative stability of stored at 37oC of SC-CO2 refined oil was much better than chemically refined oil, and was almost equal to crude oil.
Results indicated that SC-CO2 refined oil was with good quality. This study may provide the basis for a potential refining process of fish oil.
| Identifer | oai:union.ndltd.org:TW/089NTU00252003 |
| Date | January 2001 |
| Creators | Chih-Sung Yang, 楊志頌 |
| Contributors | Lucy Sun Hwang, 孫璐西 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 96 |
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