Levels Of Monoglycerides Research Articles

Glycerol and monoglycerides determination in biodiesel methyl ester from palm oil using gas chromatography

Monoglycerides and glycerol are by-products contaminants, after transesterification, in biodiesel that can lead to severe operational and engine problems such as wax precipitation, filter plugging and engine deposits. Therefore, strict regulations have been made, and accurate quality control is required. In this work, levels of monoglycerides and glycerol were determined using gas chromatography (GC) equipment with flame ionization detector (FID) refers to standard methods ASTM D6584 and EN 14105. However, the monoglycerides determination still needs firmness and validation to develop standard calibration series to fit the constituent fatty acid components of the feedstock used. This paper shows three fatty acids, i.e., monoolein, monopalmitin, and monostearin, as major components in palm-based biodiesel, which would be prepared as standard calibration and determined from commercial biodiesel samples in the determination of monoglyceride levels accurately and thoroughly. The result shows that standard solutions produce a curve with high linearity; it was above 0.998 (for free glycerol, monopalmitin, monoolein, and monostearin) and its accuracy values were >95%. However, the result for eight commercial biodiesel samples in Indonesia had a range of 0.23-0.54% w/w for total monoglycerides, 0.07 to 0.14 (% w/w) for total glycerol, and < 0.01% w/w for free glycerol, which was fulfilling to the ASTM D6751 and EN 14214 specification requirements.

Fatty Acids of the Liver and the Blood Plasma During the Hibernation of the Yakutian Ground Squirrel Spermophilus undulatus

Abstract—We investigated the effect of hibernation on the levels of fatty acids and monoglycerides in the liver tissue and in the blood plasma of the Yakut ground squirrel Spermophilus undulatus. In the liver tissue of dormant animals (the hibernation bout) the level of fatty acids (μg of fatty acids/mg of protein) increases by 5 times compared to the summer period. In ground squirrels that are active in the winter (a hibernation interbout), the level of fatty acids was halved compared to dormant ones. The level of monoglycerides in the liver of hibernating animals was halved compared to summer animals. The protein level (mg/g of tissue) in the liver did not change during hibernation. The level of fatty acids decreased by half in the blood plasma of animals during the hibernation and returned to summer level in active winter animals. The level of monoglycerides in the blood plasma did not change. The protein concentration in the blood plasma during hibernation is increased by 20% compared with the summer period. Changes in the level of fatty acids in the liver and blood plasma indicate the adaptive role of fatty acids in the hibernation of the ground squirrel S. undulatus. A high fat level is maintained in the liver of hibernating animals with a reduced level of fatty acid in the blood plasma during torpor. Fatty acids of the liver play a role in the return of the fatty acid plasma level to the summer level during the hibernation interbout. The analysis of our results demonstrated that the liver plays a role in the regulation of plasma lipids, acting as a depot for fatty acids with an adaptive decrease in their concentration in the blood plasma during the hibernation season. A high level of liver fatty acids can cause adaptive changes in the lipid composition of the intracellular organelles of the liver tissue during the hibernation of the ground squirrel S. undulatus.

Changes in lipid components during the development of the french bean seed (Phaseolus vulgaris)

AbstractChanges in lipid classes, fatty acid composition and distribution have been monitored during the germination, development and maturation of the French bean seed Phaseolus vulgaris. A lipase activity profile over time was also determined. Ungerminated seeds contained high levels of triglycerides and free fatty acids, but low levels of polar lipids, monoglycerides, and diglycerides. Five days after germination there was a decrease in the quantity of triglycerides and free fatty acids and a concomitant increase in the levels of monoglycerides, diglycerides, and polar lipids. As development and maturation progressed, triglycerides increased substantially at the expense of mono‐ and diglycerides. Ungerminated seeds contained high levels of C20‐C22 fatty acids which decreased after germination with a concomitant increase in C16‐C18 unsaturated fatty acids. A study of the fatty acid distribution among the different classes of lipids demonstrated that 55% of the unsaturated fatty acids in the ungerminated seeds were present in the triglycerides, whereas the remainder were distributed among the mono‐ and diglycerides as well the other lipid classes (free fatty acids, polar lipid, and sterols). Five days after germination, the majority of these unsaturated fatty acids were found in the glyceride form. Overall the lipid classes, fatty acid composition and distribution changes during development and maturation of the French bean seed indicated that it shares many of the characteristics of soya bean development.

INHIBITION OF ASPERGILLUS GROWTH AND EXTRACELLULAR AFLATOXIN ACCUMULATION BY SORBIC ACID AND DERIVATIVES OF FATTY ACIDS

A study was conducted to determine the effects of sorbic acid and several derivatives of fatty acids (amides, aminimides, and monoglycerides) upon toxigenic cultures of Aspergillus flavus and A. parasiticus. A synthetic medium was inoculated with spores, incubated for 48 h at 27°C, and then supplemented with sorbic acid and fatty acid derivatives. Cultures were then incubated for an additional 5 days. Aflatoxins were extracted, separated, and quantitated. Mycelial mats were dried, weighed, and analyzed for lipid and mineral content. Cerulenin (8 μg/ml) was the most effective fatty acid derivative examined, reducing mycelial growth by 37% and completely inhibiting extracellular accumulation of aflatoxins. Other derivatives, in decreasing order of effectiveness, included M‐20 (an aminimide), lauribic, and lauricidin. Mycelia grown in the presence of fatty acid derivatives contained less phosphorus, potassium, magnesium, phosphatidyl ethanolamine, phosphatidyl serine, cholesterol, and triglycerides, but more cardiolipin, phosphatidyl choline, free fatty acids, fatty acid esters, and diglycerides. Levels of monoglycerides and cholesterol esters remained essentially unchanged. Inhibition by sorbic acid was nonspecific, affecting both mycelial growth and extracellular aflatoxin accumulation to approximately the same extent. Utilization of fatty acid derivatives for determining mechanisms of aflatoxin accumulation and lipid biosynthesis appears promising.