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排序方式: 共有2935条查询结果,搜索用时 11 毫秒
51.
A Life Cycle Assessment (LCA) study of HidroBioDiésel (HBD) was carried out. This partly renewable diesel fuel is obtained from the co-processing of soybean vegetable oil with conventional fossil fuel in hydrotreating facilities of crude oil refineries. The environmental profile of HBD was assessed for the fossil energy use and climate change impact categories. The production systems of equivalent fuels -blends of Fatty Acid Methyl Ester (FAME, a biofuel obtained by means of transesterification of vegetable oil) and mineral diesel with sulphur content below 10 ppm were also assessed for comparison purposes. The environmental performance of HBD systems compares favourably to those of FAME and diesel blends for the selected impact categories. The estimated environmental benefits of HBD (assuming a 13% renewable blend) include reductions of up to 2% in fossil energy use and 9% in climate change impacts. 相似文献
52.
The chemical, amino acid and fatty acid compositions of Sterculia urens seeds are reported. The cotyledons were found to be rich in protein (30.88%) and lipids (39.2%). The major amino acids in defatted Sterculia urens cotyledon flour (DSCF) were determined as glutamic acid, arginine and aspartic acid. Cysteine, methionine, tyrosine and histidine were observed in minor quantities. The ratio of essential to non-essential amino acids was observed to be 0.45. Among the essential amino acids, isoleucine was found to be higher than the reported FAO/WHO requirements. The GC-FID and GC–MS analysis revealed that the major fatty acids of the total lipid were stearic acid (31.72%), linoleic acid (28.83%) and palmitic acid (26.79%). Eicosadienoic acid (4.98%) and eicosatrienoic acid (2.96%) were also found in the total lipid. 相似文献
53.
Foam flotation is an effective and energy efficient method of harvesting microalgae. This study has investigated the influence of growth phase and lipid content on harvesting efficiency. The highest biomass concentration factors were gained during active culture growth. Surprisingly, the quantities of lipid recovered from microalgae harvested by foam flotation using the surfactant cetyl trimethylammonium bromide (CTAB), were significantly higher than from cells harvested by centrifugation. Further, cells harvested by CTAB-aided foam flotation exhibited a lipid profile more suited to biodiesel conversion containing increased levels of saturated and monounsaturated fatty acids. The enhanced lipid recovery was partially explained by the interaction of the cells with the surfactant, CTAB, which adsorbed onto the algae and was carried over into the total lipid extraction process. However, further evidence also suggested that CTAB promoted in situ cell lysis by solubilising the phospholipid bilayer, thus increasing the amount of extractable lipid. This work demonstrates substantial added value of foam flotation as a microalgae harvesting method beyond energy efficient biomass recovery. 相似文献
54.
55.
E. Zamora-Rojas A. Garrido-VaroE. De Pedro-Sanz J.E. Guerrero-GinelD. Pérez-Marín 《Meat science》2013
A handheld micro-electro-mechanical system (MEMS) based spectrometer working in the near infrared region (NIR) (1600–2400 nm) was evaluated for in-situ and non-destructive prediction of main fatty acids in Iberian pig (IP) carcasses. 110 IP carcasses were measured. Performance of the instrument was compared with at-line high-resolution NIRS monochromators working in two analysis modes: melted fat samples (transflectance cups) and intact adipose tissues (interactance fiber optic). Standard Error of Prediction (SEP) values obtained on the MEMS-NIRS device were: 0.68% (stearic), 1.30% (oleic), 0.55% (linoleic) and 1% (palmitic), explaining a variability of 83%, 84%, 81% and 78%, respectively. As expected, this represented a loss of predictive capability in comparison to at-line models, even with the same spectral characteristics as on the handheld device. However, the estimated total errors were at the same level for gas chromatography and NIRS analysis. This indicates that the MEMS-NIRS in-situ analysis of each individual carcass provides a cost-effective and real-time quality control system with suitable accuracy. 相似文献
56.
In this study, pumpkin seeds, called as “Ürgüp Sivrisi” and grown in Cappadocia region, were used as plant materials because of high aroma contents. In the supercritical fluid extraction of pumpkin seed oil, the effect of main process parameters as the particle size (250-2360 μm), the volumetric flow rate of supercritical solvent (0.06-0.30 L/h), the operating pressure (20-50 MPa), the operating temperature (40-70 °C), the type of entrainer (ethanol and n-hexane) and those concentrations (0-10 vol.%) on the extraction yield, the oil solubility and the initial extraction rate were investigated. A cross-over effect for the extraction of pumpkin seed oil using supercritical CO2 was determined at the operating pressure of 20-30 MPa. The maximum extraction yield obtained with entrainer free was reached 0.50 g oil/g dry seed at 600-1180 μm, 0.12 L/h, 50 MPa and 70 °C for the operation time of 5 h. The maximum extraction yield obtained with ethanol as an entrainer in the experiments was reached 0.54 g oil/g dry seed at the conditions of 600-1180 μm, 0.12 L/h, 30 MPa, 40 °C and 8 vol.% for the operating time of 2 h. The oil compositions were determined by gas chromatography analysis and the results showed that the compositions of pumpkin seed oil which were obtained by means of organic solvent extraction and supercritical fluid extraction were similar. The average oil compositions determined as 9.3 (±0.43)% palmitic acid, 7.5 (±0.6)% stearic acid, 32.3 (±0.6)% oleic acid, 48.1 (±0.6)% linoleic acid and 0.7 (±0.3)% linolenic acid. The morphological changes in the seeds were determined by the scanning electron microscopy analysis. 相似文献
57.
58.
FAME Production and Fatty Acid Profiles from Moist Chlorella sp. and Nannochloropsis oculata Biomass
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Rui C. M. Alves Sobrinho Laércio Vauchinski Renata Rodrigues de Moura Ednei G. Primel Paulo C. V. Abreu Marcelo G. Montes D’Oca 《Journal of the American Oil Chemists' Society》2015,92(3):423-430
In the present study, we investigated the production of fatty acid methyl esters (FAME) from moist Chlorella sp. and Nannochloropsis oculata biomass using a hydrolysis–esterification process. Additionally, we evaluated for the first time the fatty acid profile before and after this process. Hydrolysis of the lipid fraction was performed on a moist biomass in the presence of differing amounts of an acid catalyst in both 50 and 100 % w/w water relative to the biomass. The esterification of the crude extracts of the free fatty acids (FFA) was then investigated. The experiments show that in the presence of 50 % w/w water relative to the biomass, the hydrolysis–esterification process results in higher FFA and FAME yields. The analysis of the fatty ester profiles did not reveal any degradation of the FFA from the microalgae biomass under the hydrolysis–esterification conditions. The results were compared with both extraction–transesterification and direct transesterification processes using dry biomass. The extraction–transesterification and hydrolysis–esterification processes resulted in similar FAME yields and similar profiles of the fatty esters from dry and moist biomass materials, respectively. 相似文献
59.
Unexploited Thapsia garganica,Orlaya maritima,and Retama raetam Seeds: Potential Sources of Unsaturated Fatty Acid and Natural Antioxidants
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Nizar Tlili Houda Mejri Houda Ben Lajnef Anouer Feriani Abdelhamid Khaldi Nizar Nasri 《Journal of the American Oil Chemists' Society》2015,92(8):1175-1181
Total lipid contents, fatty acid compositions, phenolic profiles and antioxidants activities of seeds from Thapsia garganica, Orlaya maritima, and Retama raetam were investigated. The oil values were more than 26 %, except seeds of R. raetam (ca. 3 %). Unsaturated fatty acids accounted for the majority of the fatty acids (more than 75 %). Oleic and linoleic acid were the predominant fatty acids. Total phenolic compounds (24–104 mg GAE g?1 DR), total flavonoids (4–102 mg QE g?1g DR), total tannins (28–85 mg GAE g?1 DR) and condensed tannins (0.62–131 mg CE g?1 DR) were also determined. The antioxidant activities using different assays were evaluated. The predominant detected classes were the phenolic acids (42–85 %) and the flavonoids (11–48 %). The major phenolic acids were caffeic, trans‐4‐hydroxy‐3‐methoxycinnamic, p‐coumaric, and gallic acid. The predominant flavonoids were quercetin, luteolin, naringin, apigenin, and kaempferol. This study brings attention to the medicinal importance of these species as a source of oil and antioxidant molecules. 相似文献
60.
Ángeles Guinda Mirela Rada Mohamed Benaissa Ibtissam Ourrach José Antonio Cayuela 《Journal of the American Oil Chemists' Society》2015,92(8):1143-1151
The suitability of using visible/near infrared spectroscopy (Vis/NIR), as a rapid and non‐destructive technique for monitoring the quality of argan seeds (Argania spinosa Skeels) was studied. The analyzed parameters were the fatty acid composition of argan seed oil, seed moisture content, seed oil content and oil stability index (OSI). The ratio between major unsaturated and saturated fatty acids (U/S) during the oxidation assay at constant temperature was studied. Values from infrared drying were used as a laboratory reference for the moisture. Argan seed oil content was determined by Soxhlet extraction. A fatty acid analysis was carried out by gas chromatography and the OSI was determined by the Rancimat test. Predictive models of argan seed moisture, ratio U/S and OSI showed good accuracy. Therefore, Vis/NIR measurements can be used for controlling several argan seed quality parameters. This procedure might be of interest to the argan oil industry, which is currently in the process of modernization and expansion. 相似文献