| Abstract: |
V. SUMMARY AND CONCLUSIONHigh intake of total dietary fat is associated with increased risk for obesity, some types of caner and possibly gallbladder disease. Epidemiologic and clinical studies provide strong and consistent evidence for the relationship between saturated fat intake, high blood cholesterol, and increased risk for coronary heart disease.A reduction of energy intake through a reduction of dietary fat intake by modifying the diets, however, successful reduction of fat consumption has not been fully achieved. The food industry, in response to consumer demands, has recently focused attention on the development of non fat, reduced fat, fat mimetics, and low calorie foods. Some of these fat substitutes are carbohydrates polyesters such as sucrose polyesters.Transesterification of vegetable oils catalyzed by methanolic sodium hydroxide reprudcible and quantitative conversion of triglycerides to fatty acids methyl esters. This reactions required no heating, few minutes (2-5) and anhydrous conditions.Sucrose polyesters was synthesized by interesterification between sucrose and fatty acid methyl esters. The reaction conditions were reaction time (11.5 h), synthation temperature (144° ± 0.5°C), high vaccum and substrate molar ratio of (11.4 : 1) (FAME : sucrose). The finale product (SPE) was purified by washing, bleacing and finally using silica gel column chromatography. The pure SPE was subjected to structural confirmation using IR and H1-NMR and examination of it’s physical properties. The results can be summarized as follows:1. The yields of vegetable oils methyl esters are (85 , 80 and 70% of oils by weight) for palm, safflower (Giza 1) and peanut (Giza 5) oils, respectively.2. The IR spectrum data show asymmetrical stretching and stretching vibrations of the methyl and methylene groups of the fatty acids chains in the region of 3000, 2860 cm-1. However, an absorption band at 1740 cm-1 by ester carbonyls in the IR spectrum of palm, safflower (Giza 1) and peanut (Giza 5) SPE and was absent in the IR spectrum of sucrose. This indicates that the fatty acid chains present in SPE are esterified to sucrose.3. The IR spectrum data show an absorption band of hydroxyl group at 3335 cm-1 in the IR spectrum of sucrose which is absent in the IR spectrum of palm, safflower (Giza 1) and peanut (Giza 5) SPE. This indicates that all hydroxyl groups in sucrose were esterified.4. The H1- NMR spectra of sucrose and SPE of palm, safflower (Giza 1) and peanut (Giza 5) SPE show signals of methyl group on the omega end of fatty acid chains, methylene group of fatty acids chains and methine groups connected to double – bonded carbon protons were located at 0.799 – 0.826, 1.201 – 1.226 and 1.933 – 1.945 ppm, respectively.5. Signals from the protons of hydroxyl groups were observed at 4.2 – 4.7 ppm in the spectrum of sucrose but were not observed in the spectra of palm, safflower (Giza 1) and peanut (Giza 5) SPE. These results show that the fatty acids were esterified to sucrose molecules and the free hydroxyl groups were no longer present in SPE molecules.6. Both the IR and H1-NMR data indicate that palm, safflower (Giza 1) and peanut (Giza 5) SPE were successfully synthesized by interesterification.7. The refractive index (at 40°C) of palm, safflower (Giza 1) and peanut (Giza 5) SPE were 1.4673, 14721 and 1.470, respectively which were slightly higher than that of palm, safflower (Giza 1) and peanut (Giza 5) oils (1.4671, 1.4674 and 1.4635, respectively).8. The specific gravities (Sp. gr) at (20°C) of palm, safflower (G.za 1) and peanut (Giza 5) SPE were 0.948, 0.930 and 0.947, respectively which were slightly higher than that of palm, safflower (Giza 1) and peanut (Giza 5) oils (0.9452, 0.9228 and 0.916, respectively).9. The viscosities of SPE for palm, safflower (Giza 1) and peanut (Giza 5) were 489, 192 and 292.3, respectively and approimxately similar to the viscosities of palm, safflower (Giza 1) and peanut (Giza 5) oils which were 488, 140 and 291, respectively.
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