Effect of Processing Treatment on Comjugated Linoleic Acid Content of Chicken Egg Yolk
| Autor: | En-Hau Lin, 林恩豪 |
|---|---|
| Rok vydání: | 2002 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 90 Conjugated linoleic acid (CLA) is a collective term for a mixture of geometric and positional isomers of octadecadienoic acid (18:2) in which the double bonds are conjugated rather than methylene-separated as they are in linoleic acid (18:2, cis-9, trans-12). CLA is an intermediate in the course of the conversion of linoleic acid (LA) to oleic acid by the rumen bacterium Butyirivibrio fibrisolvens. CLA is abundant in milk, dairy products, and the meat of ruminant animals. It is present primarily in the cis-9, trans-11 modification. The object of this study is to raise the amount of CLA of chicken egg products during processing. The results indicate that: (1) the concentrations of CLA in commercial egg products are significantly higher than fresh chicken egg (0.83 mg/g oil), and the distribution of cis-9, trans-11 and trans-10, cis-12-CLA are effected by process. (2) The concentrations of CLA increased 1.12 fold in chicken egg yolk by alkaline treatment at 10th day, but decrease 1.20 fold by alkaline treatment at 20th day. The concentrations of CLA slightly increased by 70℃ heating 20 mins, but decreased significantly by 85℃ heating 20 hrs after alkaline treatment at 10th day. (3) The concentrations of CLA decreased 1.17 fold by acidic treatment for 48 hrs. (4) The concentrations of CLA decreased 1.63 fold by salt treatment at 10th day, and significant decreased the ratio of cis-9, trans-11-CLA to total CLA after salt treatment for 20 days. (5) The concentrations of CLA and distribution of cis-9, trans-11-CLA would not significantly different during alcoholic treatment period. (6) The concentrations of CLA significantly increased with heating temperature (70, 80, 90℃). The concentrations of CLA would increase first and then decrease significantly during baking (85, 95, 105℃) period. Both of the two treatments would not cause difference significantly on the ratio of cis-9, trans-11-CLA to total CLA. (7) The concentrations of CLA extracted in 50℃ would be the highest among different extractive temperature (50, 260, 270, 280, 290℃), and CLA would be seriously destroyed in 280 and 290℃. Furthermore, the ratio of cis-9, trans-11-CLA to total CLA would decreased significantly with the increase of extractive temperature. (8) The results of effects of solid content and pasteurization temperature on CLA content of fermented whole liquid egg indicated that the CFU/mL of lactic acid bacteria would increase with the raise of solid content. The CFU/mL of lactic acid bacteria in fermented whole liquid egg media pasteurized in 70℃ would be the highest. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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