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Biology and biotechnology of modifie...

Hamam, Fayez.

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Biology and biotechnology of modified oils.

紀錄類型:	書目-語言資料,印刷品 : Monograph/item
正題名/作者:	Biology and biotechnology of modified oils./
作者:	Hamam, Fayez.
面頁冊數:	217 p.
附註:	Source: Dissertation Abstracts International, Volume: 68-09, Section: B, page: 5646.
Contained By:	Dissertation Abstracts International68-09B.
標題:	Agriculture, Food Science and Technology. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=NR31317
ISBN:	9780494313176

Biology and biotechnology of modified oils.
Hamam, Fayez.

Biology and biotechnology of modified oils. - 217 p.

Source: Dissertation Abstracts International, Volume: 68-09, Section: B, page: 5646.

Thesis (Ph.D.)--Memorial University of Newfoundland (Canada), 2007.

The objectives of this study were three fold and these are described in three parts. In the first part incorporation of long-chain n-3 fatty acids (FA) into three types of high-laurate canola oils was examined. Incorporation of the n-3 FA, namely eicosapentaenoic acid (EPA, C20: 5 n-3), docosapentaenoic acid (DPA, C22: 5 n-3), and docosahexaenoic acid (DHA, C22: 6 n-3) into three types of high-laurate canola oils, known as Laurical 15, 25, and 35 with 15, 25, and 35% oleic acid content, respectively, was carried out.

ISBN: 9780494313176Subjects--Topical Terms:

1017813
Agriculture, Food Science and Technology.

Biology and biotechnology of modified oils.
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100 1 $a Hamam, Fayez. $3 1272209
245 1 0 $a Biology and biotechnology of modified oils.
300 $a 217 p.
500 $a Source: Dissertation Abstracts International, Volume: 68-09, Section: B, page: 5646.
502 $a Thesis (Ph.D.)--Memorial University of Newfoundland (Canada), 2007.
520 $a The objectives of this study were three fold and these are described in three parts. In the first part incorporation of long-chain n-3 fatty acids (FA) into three types of high-laurate canola oils was examined. Incorporation of the n-3 FA, namely eicosapentaenoic acid (EPA, C20: 5 n-3), docosapentaenoic acid (DPA, C22: 5 n-3), and docosahexaenoic acid (DHA, C22: 6 n-3) into three types of high-laurate canola oils, known as Laurical 15, 25, and 35 with 15, 25, and 35% oleic acid content, respectively, was carried out.
520 $a Production of SL via acidolysis of Laurical 15 with EPA, DPA, and DHA was carried out using five lipases from Candida antarctica, Mucor miehei, Pseudomonas sp., Aspergillus niger, and Candida rugosa. Pseudomonas sp. lipase gave the best incorporation of EPA, DPA, or DHA into Laurical 15. Optimum reaction conditions for EPA incorporation into Laurical 15 were 4% enzyme load, and an oil to EPA mole ratio of 1:3 at 45°C over 36 h. For DPA incorporation into Laurical 15, the optimum conditions were 6% lipase amount, and an oil to DPA mole ratio of 1:2 at 35°C over 48 h. Similarly, incorporation of DHA into Laurical 15 was best achieved at a mole ratio of oil to DHA of 1:3, 10% lipase concentration, at 35°C over 48 h. Lauric acid remained mostly esterified to the sn-1,3 positions while EPA, DPA or DHA was also located mainly in the sn -1,3 positions of the modified oils. The modified oils were more prone to oxidation than their unmodified counterparts, as evidenced by the 2-thiobarbituric acid reactive substances (TBARS) test.
520 $a In the second part, the effect of chain length, number of double bonds, the location and geometry of double bonds, the reaction conditions, and reactivity of different lipases on the incorporation of selected long-chain FA (LCFA) into triacylglcerols, such as tristearin, triolein, trilinolein, and trilinolinin, was studied. Five lipases were screened for their effect on catalyzing the acidolysis of tristearin with selected LCFA. Candida antarctica lipase catalyzed a higher incorporation of oleic acid (OA), gamma-linolenic acid (GLA), EPA, and DHA into tristearin. Candida rugosa lipase catalyzed higher incorporation of linoleic acid (LA), alpha-linolenic acid (ALA), and conjugated linoleic acid (CLA) into tristearin. Thus, these two lipases might be considered as promising biocatalysts for acidolysis of tristearin with selected LCFA. EPA was better incorporated into tristearin than DHA using the enzymes tested. LA incorporation was better than CLA, and ALA was more reactive than GLA. In another set of experiments, a mixture of equimole amounts of C18 FA were used for acidolysis of tristearin with C18 FA at mole ratios of 1:1, 1:2, and 1:3. As the mole ratio of C18 FA increased from 1:1 to 1:3, incorporation of OA and LA increased except for the reaction catalyzed by A. niger and C. rugosa. In general, the highest incorporation of n-3 FA into tristearin was obtained at a mole ratio of tristearin to n-3 FA of 1:3.
520 $a Incorporation (%) of a mixture of C18 FA into trilinolein using the most effective lipase from Pseudomonas sp. was in the order of SA>OA>GLA>ALA>CLA. The order of incorporation of n-3 FA into trilinolein using lipases from C. antarctica and M miehei was ALA>EPA>DPA>DHA. Meanwhile, the degree of n-6 FA incorporation into trilinolein with Pseudomonas sp. lipase was in the order of GLA>AA>CLA.
520 $a In the third and final part, reasons behind compromised stability of the SL so produced were explored. For the first time, the removal of endogenous antioxidants from modified oil, at least partially, was demonstrated to occur through the formation of tocopheryl esters during the acidolysis reaction. Tocopherols in the oils were found to react with carboxylic acids present in the medium, thus leading to the formation of tocopheryl esters that do not render any stability to the resultant modified oils. Therefore, compromised stability of the structured lipids could, at least be partially, be explained on a molecular basis because of the formation tocopheryl esters that do not exhibit any in vitro antioxidant activity. (Abstract shortened by UMI.)
590 $a School code: 0306.
650 4 $a Agriculture, Food Science and Technology. $3 1017813
690 $a 0359
710 2 $a Memorial University of Newfoundland (Canada). $3 1017906
773 0 $t Dissertation Abstracts International $g 68-09B.
790 $a 0306
791 $a Ph.D.
792 $a 2007
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=NR31317