碩士 / 國立海洋大學 / 食品科學系 / 89 / The odor of chicken oil is the factor limiting its food use. The chicken adipose fat was dry-rendered at 140℃ for 30 min gave high yield (78.5 % ). The fatty acid profile of the oil so obtained consisted of 56.23 % monoenoic acids in which oleic acid was the major of MUFA; it contributed to 388.4 mg/g oil.
Treatment of this oil at 33℃ for 30 min with an extract of lipoxygenase from a green marine macroalgae, Ulva conglobata, resulted in an insignificant reduction in monoenoic acids, i.e. 0.19 % of total monoenoic acids, and 0.20 % of the oleic acid, but a significant of 33.0 % decrease in total polyenoic acids.
The chicken oil stored at 4℃ for eight weeks, did not result in changes of indices e.g. POV, A 234 nm and A 268 nm. At 45℃, the chicken oil increased in POV, A 234 nm and A 268 nm to 2.9, 1.2 and 2.0 fold, respectively. The adipose fat was more susceptible to oxidation than the chicken oil. The adipose fat stored at 4℃ for 30 days showed increases in POV, A 234 nm were 1.7 fold and A 268 nm was 1.84 fold of chicken oil.
A noticeable improvement in odor of chicken oil was observed by sensory evaluation. The differences in the volatile compounds and their odor notes are compared using a GC-sniffing technique. Increased LOX activity in treatment of chicken oil produced high concentration of the desirable unsaturated aldehydes, ketones and alcohols that resemble odors of apple, citrus, melon, fruit and algae. A reduced “chicken fat odor” was observed while oily odor note maintained after treatment with algal lipoxygenase for up to 2 hours.
The modified chicken oil consisted of more desirable volatile compounds: ethyl acetate, pentanal, 2-pentyl furan, E-2-heptenal, nonanal than the original chicken oil, provided fruity and tea-leave aroma and less undesirable volatile compounds of heptanal, 2,4-heptadienal, 2,4- nonadienal, dodecanal, tetradecanol, reduces chicken oil and oxidized odor note.
| Identifer | oai:union.ndltd.org:TW/089NTOU0253004 |
| Date | January 2001 |
| Creators | Nai Ting Ma, 馬乃婷 |
| Contributors | Bonnie Sun Pan, 孫寶年 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 71 |
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