Average Number Of Double Bonds Research Articles

Impact of St. John’s wort extract Ze 117 on stress induced changes in the lipidome of PBMC

BackgroundMembrane lipids have an important function in the brain as they not only provide a physical barrier segregating the inner and outer cellular environments, but are also involved in cell signaling. It has been shown that the lipid composition effects membrane fluidity which affects lateral mobility and activity of membrane-bound receptors.MethodsSince changes in cellular membrane properties are considered to play an important role in the development of depression, the effect of St. John’s wort extract Ze 117 on plasma membrane fluidity in peripheral blood mononuclear cells (PBMC) was investigated using fluorescence anisotropy measurements. Changes in fatty acid residues in phospholipids after treatment of cortisol-stressed [1 μM] PBMCs with Ze 117 [10–50 µg/ml] were analyzed by mass spectrometry.ResultsCortisol increased membrane fluidity significantly by 3%, co-treatment with Ze 117 [50 µg/ml] counteracted this by 4.6%. The increased membrane rigidity by Ze 117 in cortisol-stressed [1 μM] PBMC can be explained by a reduced average number of double bonds and shortened chain length of fatty acid residues in phospholipids, as shown by lipidomics experiments.ConclusionThe increase in membrane rigidity after Ze 117 treatment and therefore the ability to normalize membrane structure points to a new mechanism of antidepressant action of the extract.

Spectroscopic characterization and thermal behavior of baru nut and macaw palm vegetable oils and their epoxidized derivatives

The ability to produce new and renewable, epoxidized Brazilian vegetable oils from baru nut (Dipteryx alata Vogel) and macaw palm (Acrocomia aculeata) oil, using a fast and clean heterogeneous catalytic method, was investigated. The Wijs method and Proton Nuclear Magnetic Resonance (1H-NMR) analysis were utilized, and compared to one another, to calculate the iodine value (IV), average number of double bonds (DBaverage) and fatty acid content, and thus degree of epoxidation, for both vegetable oils. This analysis indicated that alkene conversions of >99% and 95.3% were obtained for baru nut oil and macaw palm oil, respectively; which is an excellent result when compared with some works in literature. The epoxidized Baru nut oil is a solid at room temperature, which was related to the percentage of mono-unsaturated fatty acids present in its structure. Epoxide samples were also analyzed via mid-Infrared Spectroscopy and 13C NMR analysis. Thermogravimetry-differential thermal analysis (TG-DTA) was used to determine the thermal stability of these epoxidized oils. Differential Scanning Calorimetry (DSC) also provided information about their crystallization, melting and solid-solid transition processes.

A study on the effects of compositional variations of biodiesel fuel on its physiochemical properties

The objective of the present work is to alter the composition of palm biodiesel and study its effects on fuel properties. As the fatty acid methyl ester composition of biodiesel has an influence on its properties, it can be varied to alter the properties as desired. Palm biodiesel was blended with various neat methyl esters on a 10%, 15% and 20% volume basis. Kinematic viscosity, heating value, density and surface tension of the 34 prepared biodiesel samples were determined and the trends followed were studied to establish the effects. The viscosity of biodiesel decreased with a decrease in methyl oleate concentration and the degree of unsaturation. An 80% palm +20% methyl octanoate blend exhibited the least viscosity. The heating value of the sample was found to be influenced by the changes in the methyl esters’ chain length, the average number of single bonds and the average number of double bonds. Apparently, 80% palm +20% methyl stearate has the highest heating value. Not great appreciable change in density was found, but the surface tension of the blends prepared was influenced by changes in the average number of carbon atoms. An 80% palm +20% methyl octanoate mix exhibited the least surface tension of the fuel blends. Based on the measured composition and property data, a multi-linear regression approach was used to develop correlations to predict the properties of biodiesel from its composition, which is validated using samples other than those used as inputs to develop the model. Further, ANN is used to predict the properties of biodiesel fuels based on their composition. The present investigation could further be extended to study the effects of compositional variations of biodiesel on other properties, which would help in arriving at an ideal biodiesel composition for automotive engine applications.

Prediction of Liquid Specific Heat Capacity of Food Lipids.

The specific heat capacity of food products is widely used in process design. Improvements of current models to predict specific heat capacity of food products will assist in the development of efficient processes and in the control of food quality and safety. Furthermore, the understanding of how changes in chemical structure of macromolecular components of foods effect thermophysical properties may begin to allude to models that are not just empirical, but represent portions of the differences in chemistry.

Analysis of 22 vegetable oils’ physico-chemical properties and fatty acid composition on a statistical basis, and correlation with the degree of unsaturation

Abstract The aim of the current work was to gather the largest possible sample of published data for vegetable oils properties, and conduct a statistical analysis in order to evaluate average values for all properties and for their fatty acid composition. A second objective was to investigate possible correlations between the properties and the degree of unsaturation. In order to achieve both tasks, the available literature on vegetable oils properties and their fatty acid composition was scanned from many well-established databases. In total, 695 papers were gathered that provided 550 different data series of oils properties and 536 of fatty acid composition, for 22 different oils. From the statistical analysis, collective results were derived for each property and quantified based on the specific oil. The effects of unsaturation were investigated too with separate best-fit linear curves provided for each interesting property with respect to the average number of double bonds. Unlike biodiesels, however, only a few (moderately) significant statistical correlations could be established between the vegetable oils properties and the degree of unsaturation, namely for cetane number, cloud and pour point and oxidation stability.

Effect of fatty acid composition on ignition behavior of straight vegetable oils measured in a constant volume combustion chamber apparatus

Straight vegetable oils attracted attention several times as alternative fuel for mobile machinery. Certain efforts have already been undertaken to enable the usage of the high viscous oils in compression ignition engines. While physical properties are well specified for different kind of oils, only few information is available on the ignition behavior of vegetable oils under modern engine like conditions. Therefore, the ignition behavior of nine different vegetable oils and two oil mixtures was investigated using the Advanced Fuel Ignition Delay Analyser (AFIDA). The AFIDA is a modern constant volume combustion chamber apparatus equipped with a high pressure injection system. Analysis was performed at combustion chamber temperatures ranging from 796K to 967K and at air density levels of 4.7kg/m3, 9.3kg/m3 and 17.7kg/m3. Ignition behavior was correlated to the structure indices average number of carbon atoms and average number of double bonds. Both were calculated using the fatty acid composition of the oils. Ignition delay decreased with rising temperature and air density. Coconut oil ignited first at every temperature except for the lowest air density level. Start of combustion was always last for linseed oil, followed by camelina and soybean oil. Ignition delay increased linearly with rising average number of double bonds and decreasing average number of carbon atoms. The effect of the average number of double bonds on ignition delay was more pronounced than that of carbon chain length. Fatty acids with two or more carbon-carbon double bonds led mostly to a stronger increase in ignition delay compared to those with only one double bond.

Emission behaviour of vegetable oil fuel compatible tractors fuelled with different pure vegetable oils

The emission behaviour of pure vegetable oils to be used as a fuel was researched using two vegetable oil fuel compatible tractors. The tractor engines were equipped with a common-rail and pump-line injection system. For the research eight different vegetable oils, one vegetable oil mixture and diesel fuel were used. Vegetable oils are basically triacylglycerides and can be characterised by the two structure indices average number of carbon atoms (AC) and average number of double bonds (ADB). The results show that both tractors can be operated with vegetable oils and diesel fuel at about the same level of efficiency. Specific test cycle emissions of nitrogen oxides (NOX) tend to be higher while specific carbon monoxide (CO), hydrocarbon (HC) and particle mass (PM) emissions tend to be lower with the vegetable oils compared to diesel fuel.The emission behaviour of the two tractors was influenced by the type of vegetable oil used.The differences were dependent on the operation mode. At average and high load operation points the emissions of CO, HC and PM were at the same level, whereas the NOX emissions were rising with increasing ADB of the vegetable oils. At low load and idle operation the emissions of CO, HC and PM were rising with increasing unsaturation respectively increasing ADB of the vegetable oils. The observed increase of NOX at average and high load could not be recognized anymore at low load and idle and is even reversed for one tractor. This indicates deteriorated combustion with increasing unsaturation of the vegetable oils at idle and low load.

Excluding the di-unsaturated alkenone in the UK37 index strengthens temperature correlation for the common lacustrine and brackish-water haptophytes

Alkenone unsaturation indices, represented by either UK37 or UK′37, are important tools for paleoclimate studies. The UK37 index is a reflection of the average number of double bonds from di-, tri-, tetra-unsaturated alkenones, but UK′37 excludes the C37:4 in the calculation. Extensive studies indicate UK′37 provides better regressions against in situ Sea Surface Temperatures (SST) than UK37 and is the most widely used SST proxy. However, recent studies have shown that including C37:4 alkenones for lacustrine or brackish water haptophytes such as Ruttnera (Chrysotila) lamellosa and Isochrysis galbana improves temperature correlations although there are still significant deviations at the extreme high and low temperatures. In this study, we use new culture-based calibration experiments alongside published culture data and in situ water column or surface sediment data, to demonstrate that a further improved temperature calibration for alkenones is, in fact, achieved when the di-unsaturated alkenone is excluded from the computation of the unsaturation index. We propose new indices, termed UK″ [UK″37=C37:3/(C37:3+C37:4) or UK″38=C38:3/(C38:3+C38:4)], for lacustrine, brackish and estuarine waters. Our observation suggests that di-unsaturated alkenones play a less important role than tri- and tetra-unsaturated alkenones in regulating cell functions to temperature variations in lacustrine and brackish waters. We suggest using UK″ indices for paleotemperature reconstructions in the lacustrine and estuarine settings.

Estimation of surface tension of fatty acid methyl ester and biodiesel at different temperatures

Surface tension (γ) is an important physical property of biodiesel for atomization and complete combustion in the diesel engine. In this study, the Martin’s rule of free energy additivity is extended to cover the free energy of interfacial interaction of a liquid. Finally, an equation (γ=60.211−0.4307z−0.1125T+0.00207zT+3.676m−0.00893mT) is derived for estimation of the surface tension of an individual fatty acid methyl ester (FAME), where T, z and m are absolute temperature, number of carbon atoms and number of double bond(s) of fatty acid, respectively. When the proposed equation was used for estimation of the surface tension of FAMEs, the deviation range was 0.03–5.54% and the average absolute deviation (AAD) was 1.32% at temperature between 20 and 100 °C.Also, the proposed equation can be used for estimation of the surface tension of a biodiesel. In this case, the average carbon numbers (zavg) and average number of double bonds (mavg) must be used in place of z and m, respectively. Thus, the prior knowledge of surface tension of individual FAME is not necessary. The estimated surface tensions of biodiesels at temperatures between 30 and 80 °C were in good agreement with the literature values. The deviation range was 0.10–5.70% and the AAD was 2.09%.

A statistical investigation of biodiesel physical and chemical properties, and their correlation with the degree of unsaturation

Abstract In the present work, a detailed statistical investigation is conducted in order to a) assess the average values of all properties (incl. fatty acid composition) of the most investigated biodiesels and b) quantify the effects of feedstock unsaturation on the physical and chemical properties of the derived methyl ester. To this aim, the available literature on biodiesel properties and fatty acid composition was gathered (more than 750 papers published in International Journals and Conferences), and the reported measurements are statistically analyzed with respect to the feedstock and its chemical composition and structure; in total, 26 different biodiesel feedstocks are studied, comprising of twenty-two edible and non-edible vegetable oils and four animal fats. From the analysis, collective results and statistical data are derived for each property that are then compared with the European and American specifications. The effects of unsaturation are investigated with separate best-fit linear curves provided for each interesting property with respect to the average number of double bonds. The various trends observed are discussed and explained based on fundamental aspects of fuel chemistry and on the consequences they have on real engine operation.

The impact of single and double hydrogen bonds on crystallization and melting regimes of Ajwa and Barni lipids

The present study was conducted to assess the impact of single and double hydrogen (H2) bonds of the prominent long chain triacylglycerols (TAGs) of Ajwa and Barni lipids. The impact of double H2 bond was in situ monitored in order to mitigate the problem of fat agglomeration and crystal aggregation. HPLC data demonstrated that the contents of 1,2-dioleoyl-3-linoleoyl-sn-glycerol (OOL) of Ajwa and Barni lipids were 13.78% and 16.24%, whereas, their relative contents for 2,3-dilinoleoyl-1-oleoyl-sn-glycerol (OLL) were 14.45% and 11.05%, respectively. The impact of double H2 bonds dropped the solid fat content (SFC) of Ajwa lipid from 1% at 20°C to 0.5% at body temperature (37°C), taking Barni lipid as reference. Their impact reduced the transition temperature 2 times and gained an enthalpy (ΔH) of 4.37J/g and 2.31J/g during crystallization and melting regimes, respectively. This study revealed that the increase in the average number of double bonds within the aliphatic structure of the long chain TAGs enhanced the chemical structure of Ajwa and Barni lipids to participate as functional food ingredients.

Graphical method to select vegetable oils as potential feedstock for biodiesel production

AbstractChemical compositions of 80 vegetable oils were collected from literature and the properties of the obtainable biodiesel (methyl esters) have been predicted by empirical relationships. The purpose has been to check the viability of predicting if a biodiesel could meet the EN 14214 standards knowing only the fatty acid profile (FAP) of the parent oil. Two parameters were used in this investigation: (i) average number of carbon atoms in the fatty acid chains, (ii) average number of double bonds (CC) per molecule. Two new empirical relationships have been proposed to predict the viscosity and the cetane number of biodiesel from the two parameters. The range of values of the two parameters leading to biodiesel meeting the EN 14214 standard for viscosity, cetane number, iodine value, and cold filter plugging point have been graphically obtained by overlapping the corresponding level surfaces.Practical applications: This work provides biodiesel producers with indications of the quality of biodiesel without the need for analytical testing of the product (indeed, of the product itself). Only the fatty acid profile of the starting vegetable oil is required. The quality of biodiesel can be estimated by using a chart developed in this work, allowing to estimate, e.g. if the biodiesel meets the European standards. The work can be useful to rapidly screen oil seed crops in studies of genetic engineering that require high throughput.

Ex Vivo Proton NMR Analysis and Characterization of Thymus Lipid Metabolites and their Variation with Age in C57BL/6 Mice

Application 1H NMR spectroscopy techniques to the ex vivo study of thymus of 0.5-24 month-old C57BL/6 mice allowed the identification, the quantification and the estimation of some structural parameters (length and unsaturation) of various lipids in the thymus and their changes with age. An initial decrease of lipid metabolites in the thymus from 0.5 to 1 month of age was followed by large raises on further ageing, with 14, 8, and 4 fold increases for the total lipid content, fatty acids and glycerides, respectively, which correlated positively with age and negatively with thymus involution. The estimated average number of methylene groups per lipid chain essentially doubled its value from approximately 4-5 for the youngest mice to around 8 for the elderly, while the values obtained for the average number of double bonds per chain decreased with age from about 1-0.9 at 0.5/1 months of age to 0.6-0.7 for 18/24 months-old mice. The combination of NMR and histological data allowed studying the age-associated changes of the contribution of adipose- derived lipids to the total lipid content of the thymus and the amount of adipose tissue infiltrating the thymus. Both parameters initially showed a decrease from 0.5 months of age to (the adipose-free thymus at) 1 month of age. Afterwards, a continuous increase was observed on ageing: at 2 months about 55% of the lipids in the thymus were adipose-derived, while at 24 months they amounted to as much as about 95% of the total lipid content; for the same age-period, the estimated minimum adipose lipid content in the thymus changed from about 0.26% to 4.5%. Keywords: Aging, adipose tissue, 1H NMR, spectroscopy, lipids, mice, thymus involution, fatty acids, glycerides, methylene, adipose- derived lipids, T cells, thymopoiesis, thymectomy, homeostasis, epithelial cells, connective tissue, stem cells, mesenquimal stem cells, chemokines, stroma cell, adipocyte, sodium tetradeuterated trimethylsilylpropionate, homogenization, resonance, apodization, WET scheme, spin-locking scheme, Normalized thymus signals, Relative thymus signals, metabolite, hematoxylin-eosin, Pearson correlation test, correlation coefficient, TOCSY spectra, acylglyceride, puberty, significant correlation, immunocompetency, atrophy, esterified, non-esterified, glucose, hypothalamicpituitary-adrenal (HPA), hypothalamic-pituitary-gonadal (HPG), palmitic acid, lipodystrophies

Ex Vivo Proton NMR Analysis and Characterization of Thymus Lipid Metabolites and their Variation with Age in C57BL/6 Mice

Application (1)H NMR spectroscopy techniques to the ex vivo study of thymus of 0.5-24 month-old C57BL/6 mice allowed the identification, the quantification and the estimation of some structural parameters (length and unsaturation) of various lipids in the thymus and their changes with age. An initial decrease of lipid metabolites in the thymus from 0.5 to 1 month of age was followed by large raises on further ageing, with 14, 8, and 4 fold increases for the total lipid content, fatty acids and glycerides, respectively, which correlated positively with age and negatively with thymus involution. The estimated average number of methylene groups per lipid chain essentially doubled its value from approximately 4-5 for the youngest mice to around 8 for the elderly, while the values obtained for the average number of double bonds per chain decreased with age from about 1-0.9 at 0.5/1 months of age to 0.6-0.7 for 18/24 months-old mice. The combination of NMR and histological data allowed studying the age-associated changes of the contribution of adipose- derived lipids to the total lipid content of the thymus and the amount of adipose tissue infiltrating the thymus. Both parameters initially showed a decrease from 0.5 months of age to (the adipose-free thymus at) 1 month of age. Afterwards, a continuous increase was observed on ageing: at 2 months about 55% of the lipids in the thymus were adipose-derived, while at 24 months they amounted to as much as about 95% of the total lipid content; for the same age-period, the estimated minimum adipose lipid content in the thymus changed from about 0.26% to 4.5%.

Genetic parameters for tissue and fatty acid composition of backfat, perirenal fat and longissimus muscle in Large White and Landrace pigs

Genetic parameters pertaining to the same chemical characteristics of three porcine tissues, that is backfat (BF), perirenal fat (PF) and longissimus muscle (LM), were estimated in centrally tested Large White and Landrace pigs. Animals were fed ad libitum. They were slaughtered at an average BW of 99.6 kg, and samples of BF (both inner and outer layers) and LM were removed at the 13th to 14th rib level of the carcass on the day after slaughter. The data set included 2483 animals recorded for average daily gain (ADG; 35 to 100 kg), estimated carcass lean percentage (LEAN) and lean tissue growth rate (LTGR). Among these animals, around 950 pigs were recorded for lipid content (L%) and water content (W%) of BF and LM and for fatty acid composition (FAC) of BF, whereas FAC of LM was measured on 297 pigs and L%, W%, and FAC of PF on around 210 pigs. Heritabilities (h2) and genetic correlations (ra) were estimated using REML-animal model methodology. Estimates of h2 for L%, W% and FAC of BF, PF and LM were of moderate-to-high magnitude: for example 0.47 ± 0.09 for L% of LM, 0.59 ± 0.11 for W% of BF, 0.45 ± 0.08 for the ratio of polyunsaturated to saturated fatty acids (P/S) of BF, 0.61 ± 0.15 and 0.29 ± 0.10 for the coefficient of unsaturation of lipids (UNSAT, average number of double bonds of unsaturated fatty acids) of PF and LM, respectively. Genetic correlations of L% with P/S or UNSAT were strongly negative (from −0.4 to −0.9) in BF and LM, but not in PF. The ‘between-tissue’ genetic correlations for homologous compositional traits were far from being unity (e.g. ra = 0.57 ± 0.05 ‘between’ BF and PF for UNSAT). Genetic relationships between ADG and tissue compositional traits were globally weak. By contrast, genetic correlations were moderate-to-high between carcass leanness and tissue compositional traits, especially those of fat depots: for example −0.66 ± 0.14 between LEAN and L% of BF, 0.50 ± 0.07 between LEAN and UNSAT of PF, −0.44 ± 0.08 between LEAN and L% of LM, and 0.27 ± 0.03 between LEAN and UNSAT of LM. On the basis of the parameter estimates found here, breeding for higher LTGR is expected to increase the ratio of water to lipids and the unsaturation degree of lipids in subcutaneous BF and, to a lesser extent, in PF. Tissue composition and FAC of LM would be less affected.

Anatomic and Molecular Correlates of Divergent Selection for Basal Metabolic Rate in Laboratory Mice

Proximal mechanisms describing the evolution of high levels of basal metabolic rate (BMR) in endotherms are one of the most intriguing problems of evolutionary physiology. Because BMR mostly reflects metabolic activity of internal organs, evolutionary increase in BMR could have been realized by an increase in relative organ size and/or mass-specific cellular metabolic rate. According to the "membrane pacemaker" theory of metabolism, the latter is mediated by an increase in the average number of double bonds (unsaturation index) in cell membrane fatty acids. To test this, we investigated the effect of divergent artificial selection for body-mass-corrected BMR on the mass of internal organs and the fatty acid composition of cell membranes in laboratory mice (Mus musculus). Mice from the high-BMR line had considerably larger liver, kidneys, heart, and intestines. In contrast, the unsaturation index of liver cell membranes was significantly higher in low-BMR mice, mainly because of the significantly higher content of highly polyunsaturated 22 : 6 docosahexanoic fatty acid. Thus, divergent selection for BMR did not affect fatty acyl composition of liver and kidney phospholipids in the direction predicted by the membrane pacemaker theory. We conclude that an intraspecific increase in BMR may rapidly evolve mainly as a result of the changes in size of internal organs, without simultaneous increase of the unsaturation index in cell membrane lipids.

FUNDING FOR DRINKING WATER IN CENTRAL AND NORTHERN LAO

The emission behaviour of pure vegetable oils to be used as a fuel was researched using two vegetable oil fuel compatible tractors. The tractor engines were equipped with a common-rail and pump-line injection system. For the research eight different vegetable oils, one vegetable oil mixture and diesel fuel were used. Vegetable oils are basically triacylglycerides and can be characterised by the two structure indices average number of carbon atoms (AC) and average number of double bonds (ADB). The results show that both tractors can be operated with vegetable oils and diesel fuel at about the same level of efficiency. Specific test cycle emissions of nitrogen oxides (NOX) tend to be higher while specific carbon monoxide (CO), hydrocarbon (HC) and particle mass (PM) emissions tend to be lower with the vegetable oils compared to diesel fuel.The emission behaviour of the two tractors was influenced by the type of vegetable oil used.The differences were dependent on the operation mode. At average and high load operation points the emissions of CO, HC and PM were at the same level, whereas the NOX emissions were rising with increasing ADB of the vegetable oils. At low load and idle operation the emissions of CO, HC and PM were rising with increasing unsaturation respectively increasing ADB of the vegetable oils. The observed increase of NOX at average and high load could not be recognized anymore at low load and idle and is even reversed for one tractor. This indicates deteriorated combustion with increasing unsaturation of the vegetable oils at idle and low load.

ADB HELPS FINANCE CHINA’S WATER DEVELOPMENT

The emission behaviour of pure vegetable oils to be used as a fuel was researched using two vegetable oil fuel compatible tractors. The tractor engines were equipped with a common-rail and pump-line injection system. For the research eight different vegetable oils, one vegetable oil mixture and diesel fuel were used. Vegetable oils are basically triacylglycerides and can be characterised by the two structure indices average number of carbon atoms (AC) and average number of double bonds (ADB). The results show that both tractors can be operated with vegetable oils and diesel fuel at about the same level of efficiency. Specific test cycle emissions of nitrogen oxides (NOX) tend to be higher while specific carbon monoxide (CO), hydrocarbon (HC) and particle mass (PM) emissions tend to be lower with the vegetable oils compared to diesel fuel.The emission behaviour of the two tractors was influenced by the type of vegetable oil used.The differences were dependent on the operation mode. At average and high load operation points the emissions of CO, HC and PM were at the same level, whereas the NOX emissions were rising with increasing ADB of the vegetable oils. At low load and idle operation the emissions of CO, HC and PM were rising with increasing unsaturation respectively increasing ADB of the vegetable oils. The observed increase of NOX at average and high load could not be recognized anymore at low load and idle and is even reversed for one tractor. This indicates deteriorated combustion with increasing unsaturation of the vegetable oils at idle and low load.

Determination of iodine value of palm and palmkernel oil by carbon-13 nuclear magnetic resonance spectroscopy

High resolution carbon-13 nuclear magnetic resonance ( 13 CNMR) can be used for characterization of palm oil and palmkernel oil in determining the iodine value (IV) of the oil. It is only necessary to obtain the quantitative 13 CNMR spectrum of the oil in dilute CDCl3 solution in the region of δ30.0-δ24.7 ppm, which pertains to the methylene carbons along the acyl chain from the β-carbonyl to the ω-4. From the peak areas in the spectrum the average number of double bonds per triacylglycerol molecule and the average molecular weight can be calculated and hence the IV. The IVs of 18 samples of palm and palmkernel oil have been determined by 13 CNMR and by the Official Method of the American Oil Chemists Society. There is good agreement between the two sets of IVs. Conditions for obtaining reliable IVs by this 13 CNMR method are given.

Synthesis of fast-swelling, superporous sucrose hydrogels

Sucrose was reacted with glycidyl acrylate to introduce double bonds. The extent of modification was quantitated using 13C NMR. The reaction time and the molar ratio were varied to adjust the degree of substitution. The average number of double bonds introduced in sucrose varied from 0.2 to 6.7. Since the reaction mixture contained sucrose modified with more than one double bond, its polymerization resulted in a crosslinked network of sucrose hydrogels (sucrogels). Superporous sucrogels were also prepared by adding a gas forming agent during polymerization. They swelled faster with higher swelling ratio and degraded faster in both acidic and basic conditions than sucrogels. The fast swelling superporous sucrogels can be used in various applications, including controlled drug delivery.