Home About us Contact
|
Home About us Contact | ||
|
|
||
FA Content (fa + content)
Selected AbstractsFactors influencing the fatty acid determination in fats and oils using Fourier transform near-infrared spectroscopyEUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY, Issue 9 2007Hormoz Azizian Abstract Fourier transform near-infrared (FT-NIR) technology is matrix dependent and thus highly dependent on factors that influence the absorption spectra. Ignoring these factors during the development of FT-NIR models will affect the accuracy and reliability of the classification of fats and oils and the determination of their fatty acid (FA) composition. Four factors were studied: the temperature at which samples are scanned, differences in FA chain length and number of double bonds, and the presence of non-triacylglycerol components. The results showed that an increase in the recording temperature decreased the absorption peak intensity, but not the position. FT-NIR spectral differences were linked to variations in molecular vibrations resulting from the number of carbon atoms or double bonds in the FA. The FT-NIR method could clearly differentiate between chain lengths from 10:0 to 18:0 and numbers of double bonds from zero (18:0) to three (18:3). Contaminants in triacylglycerols altered the FT-NIR spectra, resulting in increased errors in the FA content. An increased concentration of ,-sitosterol in triolein decreased or increased the observed contents of cis9-18:1 and cis11-18:1, respectively. An FT-NIR model adjusted for the phytosterol content corrected this discrepancy. The revised FT-NIR model was successfully used to provide the accurate FA compositions of commercial sunflower oils. [source] Expression of a cDNA encoding palmitoyl-acyl carrier protein desaturase from cat's claw (Doxantha unguis-cati L.) in Arabidopsis thaliana and Brassica napus leads to accumulation of unusual unsaturated fatty acids and increased stearic acid content in the seed oilPLANT BREEDING, Issue 2 2007M. Bondaruk Abstract A cDNA encoding palmitoyl-acyl carrier protein (ACP)-desaturase from cat's claw (Doxantha unguis-cati L.) was expressed in Arabidopsis thaliana and Brassica napus L. with the goal of decreasing the saturated fatty acid (FA) content of the seed oil. In general, transformation of Arabidopsis resulted in a greater change in the FA composition of the seed oil than for B. napus. An increase in palmitoleic acid (16:1cis,9) was obtained in transgenic lines, suggesting that the 16:0-ACP-desaturase cDNA was expressed in the manner originally intended. Other effects on lipid metabolism, however, were observed in the seed of transgenic plants. In Arabidopsis, there was a large increase in the proportions of cis -vaccenic acid (18:1cis,11) and cis -13-eicosenoic acid (20:1cis,13), possibly generated through elongation of 16:1cis,9. Elongation of 18:1cis,11 to 20:1cis,13, however, was not observed in B. napus indicating that certain aspects of lipid metabolism in the model plant, Arabidopsis, may not apply to B. napus. As well, the appearance of 18:1cis,11 was accompanied by a decrease in the proportion of oleic acid (18:1cis,9). Although the introduced ACP-desaturase resulted in synthesis of some unsaturated FAs, the overall saturated FA content was maintained at similar levels to the control or was enhanced. Increased levels of saturation were mainly associated with an increase in stearic acid, which unlike 16:0, is considered non-atherogenic. The results suggest that a mechanism exists further downstream in oil biosynthesis to counteract the decrease in saturation brought about by the 16:0-ACP-desaturase action. [source] Interacting effects of dietary lipid level and temperature on growth, body composition and fatty acid profile of rohu, Labeo rohita (Hamilton)AQUACULTURE NUTRITION, Issue 6 2004K. Mishra Abstract Three isonitrogenous (320 g kg,1 crude protein, casein and gelatine) semi-purified diets with 80 (L8), 130 (L13) and 180 (L18) g kg,1 lipid (sunflower oil at increasing levels and cod liver oil fixed at 50 g kg,1) at three digestible energy levels (12 096, 13 986 and 15 876 kJ kg,1 dry weight) and were tested, in triplicate, on rohu fingerlings (3.2 ± 0.08 g) at two different temperatures (21 and 32 °C). Fish were fed to apparent satiation, twice daily, at 09.00 and 15.00 h, 7 days a week for 56 days. Maximum growth was obtained at a lipid level of 80 g kg,1 (L8) at 21 °C (439.37%) and 130 g kg,1 (L13) at 32 °C (481.8%). In general growth rate was higher at 32 °C than at 21 °C at all lipid levels. Tissue monounsaturated fatty acid (MUFA) contents decreased with increasing lipid level at 32 °C, but the reverse occurred at 21 °C. At 21 °C, Polyunsaturated fatty acid (PUFA) level increased significantly (P > 0.05) over initial values, but was affected insignificantly by dietary lipid level. At 32 °C, fish fed diet L13 had more n-3 fatty acid (FA) in liver and muscle than the other two dietary groups while at 21 °C, both liver and muscle FA profiles exhibited significant change (P > 0.05) in n-3 and n-6 FA content which corresponded to variation in percent addition of dietary lipid. However, n-3/n-6 ratio was higher for fish fed diet L13 at 32 °C and diet L8 at 21 °C and may be correlated with fish growth. [source] Fatty acid composition and analysis of freshwater caridean shrimp Macrobrachium nipponense (De Haan) during spermiogenesisAQUACULTURE RESEARCH, Issue 8 2010Da-Hui Wang Abstract We analysed fatty acids (FAs) composition and the potential functions of FAs in hepatopancreas and testis of freshwater caridean shrimp Macrobrachium nipponense during testis development. The hepatopancreas presented a high unsaturated FA content of about 40%, whereas the testis showed a high level of saturated fatty acids (SFAs) with a decreasing content of 97,86% of total FAs during maturation. Several specific FAs in testis showed significant changes throughout maturation. Among SFAs, C14:0 contributed with a relatively constant high proportion of about 22%, whereas C16:0 and C18:0 contents were also at high levels but showed significant increases during maturation. Representatives of highly unsaturated fatty acids (HUFAs), such as C18:1n-9, C18:2n-6, C20:5n-3 (EPA), C20:4n-6 (AA) and C22:6n-3 (DHA) showed significant increases despite their low proportion in the gonad. These results suggest that a high content of HUFAs in hepatopancreas may represent a reservoir for sperm production. The FA C14:0 may provide a particular function. The variations of the FA profile in testis at different developmental stages reveals that C18:1n-9, C18:2n-6, C20:5n-3, C20:4n-6 and C22:6n-3 may play important roles in spermiogenesis. [source] | |||||||||||||