scholarly journals The reaction of phosphoglycolipids and other lipids with hydrofluoric acid

1974 ◽  
Vol 143 (2) ◽  
pp. 461-464 ◽  
Author(s):  
N. Shaw ◽  
A. Stead
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Free Fatty Acid ◽  
Structure Determination ◽  
Hydrofluoric Acid ◽  
Good Yield ◽  
Glycosidic Linkage ◽  
Cyclopropane Fatty Acids ◽  
Hydrolysis Of

1. The use of HF as a dephosphorylating reagent for phospholipids was examined. 2. Hydrolysis of phosphatidylethanolamine at 0°C for 24h with 60% HF gives a good yield of diglyceride. Under similar conditions phosphatidyldiglucosyl diglyceride gives diglyceride and diglucosyl diglyceride. 3. The glycolipid is also obtained from hydrolysis of glycerylphosphoryldiglucosyl diglyceride. No lyso derivative of the glycolipid could be detected and the glycosidic linkage was also stable. 4. Triglycerides, unsaturated and cyclopropane fatty acids were unaffected by the reagent. 5. 1,2-Diglycerides and 1,3-diglycerides were partially isomerized and also gave small amounts of free fatty acid and monoglyceride. 6. Monoglycerides underwent extensive rearrangement to form 1,2- and 1,3-diglycerides. 7. Lysophosphatidylethanolamine also gave 1,2- and 1,3-diglycerides as well as monoglycerides. 8. The application of this procedure to the structure determination of various phosphoglycolipids is discussed.

Validation of the Free Fatty Acid Test Kit for the Measurement of the Free Fatty Acid Content of Vegetable Oils, Fish Oils, Animal Fats (Tallows), Meat and Fish Meals, and Potato Chips and Grain-Based Snack Products: AOAC Performance Tested MethodSM 052004

2020 ◽  
Author(s):  
Virginia C Gordon I ◽  
Christopher C Rainey ◽  
Willainia C Studmire
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Free Fatty Acid ◽  
Fatty Acid Content ◽  
Animal Fats ◽  
Independent Laboratory ◽  
Test Kit ◽  
Acid Test ◽  
Snack Products

Abstract Background The Official American Oil Chemists’ Society (AOCS) Ca 5a-40 method for the determination of free fatty acids is based on titration of an ethanolic solution and requires a large volume of organic solvents, large sample aliquots, and up to 18 hours extraction time for some samples. The SafTest Free Fatty Acid Test Kit is a rapid method designed to measure the free fatty acid content of vegetable oils; fish oil; animal fats (tallows); meat meal and fish meal products; and crackers, chips, and other processed grain-based snack products using micro-analytical and membrane separation principles. Objective The study objective was to validate the SafTest Free Fatty Acid Test in one internal study, two contracted studies, and an independent laboratory study studies. Method Recovery, limit of quantitation, selectivity, robustness, stability, and consistency of the SafTest Free Fatty Acid Test were evaluated. Results Recoveries from control solutions ranged from 97 to 106%. Repeatability (RSDr) from method developer matrix studies ranged from 1.1 to 8.1%. Biases, expressed as a percentage recovery from AOCS Ca 5a-40, averaged 96.5% for olive oils, 94.0% for animal fats, and 103.9% for meat meals. Results observed in the independent laboratory study were similar. Conclusions The SafTest Free Fatty Acid Test can measure free fatty acid levels in oils, fats, meal, and snack matrices with accuracy and precision comparable to AOCS Ca 5a-40. Highlights The SafTest Free Fatty Acid Test Kit has the advantage of using reagent volumes, instrumental analysis, and easy-to-use, standardized procedures with rapid detection times for the determination of free fatty acids.

Rapid, sensitive fluorometric determination of serum triglyceride by measuring lipase-liberated fatty acids

1994 ◽  
Vol 40 (1) ◽  
pp. 14-17 ◽  
Author(s):  
J E Voysey ◽  
D C Wilton
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Serum Triglyceride ◽  
Time Interval ◽  
Serum Samples ◽  
Fluorescence Change ◽  
Displacement Assay ◽  
Catalyzed Reactions ◽  
Hydrolysis Of

Abstract A continuous fluorescence displacement assay was developed for the measurement of long-chain fatty acids and utilized in the study of triglyceride lipase-catalyzed reactions (Wilton, DC. Biochem J 1991;276:129-33). We now describe a method for the rapid measurement of triglyceride in serum with the fluorescence displacement assay. The method involves the hydrolysis of a diluted sample equivalent to 0.1 microL of original serum with excess lipase (EC 3.1.1.3) from Rhizopus arrhizus and measuring the fatty acid released after a set time interval, normally 1 min. Under the conditions of the timed assay, about 2 mol of fatty acid are released per mole of triglyceride. The released fatty acid is monitored by fluorescence change and is proportional to the concentration of triglyceride in the original serum sample. The effective range of serum triglyceride concentration that could be measured was 0.5-10 mmol/L (0.44-8.8 g/L), based on triolein standard. The assay is unique in that it measures lipase-liberated fatty acids rather than liberated glycerol and as such is not subject to many of the criticisms of the glycerol-based methods. Comparison of fasted serum samples established a high correlation between the fatty acid and glycerol methods.

scholarly journals THE IMMOBILIZATION OF LIPASE FROM MUCOR MIEHEI ON ZEOLITE MATRIX IN HYDROLYSIS OF PALM OIL PRODUCING FREE FATTY ACIDS WITH SOLVENT FREE SYSTEM

2018 ◽  
Vol 7 (2) ◽  
pp. 108-114
Author(s):  
Dwina Moentamaria ◽  
Achmad Chumaidi ◽  
Nanik Hendrawati ◽  
Girlian Girlian ◽  
Meilita Againa Mustika
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Free Fatty Acid ◽  
Free Fatty Acids ◽  
Palm Oil ◽  
Immobilized Lipase ◽  
Mucor Miehei ◽  
Oil Hydrolysis ◽  
Hydrolysis Of ◽  
Free Lipase

The enzymatic hydrolysis of palm oil can be conducted by using lipase produced from Mucor miehei to produce free fatty acid. This study aimed to compare the usage of lipase as free enzyme and as immobilized enzyme on zeolite matrix in the hydrolysis of palm oil as triglyceride producing free fatty acids which highly needed in various industrial sectors. Immobilization is an alternative hydrolysis reaction due to its usage on repetitive reaction, makes lipase reuseable, hence the whole process becomes efficient, and with moderate operational conditions. Solvent free reaction is applied, because the produced free fatty acids can be used directly in food, health, and natural flavorings industry. The palm oil used in the hydrolysis contains 0.815% initial free fatty acids as palmitate, in which water then added to it in weight ratio 1:3. Each effect of free lipase and immobilized lipase addition is 4%, 5%, 6%, 7%, 8%, and time reaction is 30, 60, 90, 120, 150 minutes are used as index to determine the amount of free fatty acids produced.  The results showed that Immobilized lipase has better ability than the free one in hydrolysis of triglyceride in palm oil producing free fatty acid with 8% lipase addition and time reaction of 120 minutes. Palm oil hydrolysis using free lipase produced the highest FFA of 1.9747% after the addition of 5% lipase concentrate, with time reaction of 60 minutes. Meanwhile, palm oil hydrolysis using immobilized lipase produced the highest FFA of 1.9747% after the addition of 8% lipase concentrate, with time reaction of 120 minutes.

CANADIAN WILTSHIRE BACON: XVII. RANCIDITY IN PORK FAT AFTER FROZEN STORAGE AND CONVERSION TO BACON

1941 ◽  
Vol 19d (3) ◽  
pp. 96-103 ◽  
Author(s):  
W. Harold White
Keyword(s):  
Fatty Acid ◽  
Free Fatty Acid ◽  
Fatty Acid Content ◽  
Frozen Storage ◽  
Antioxidant Effect ◽  
Aluminium Foil ◽  
Temperature Method ◽  
Pork Fat ◽  
Hydrolysis Of

Determination of the peroxide oxygen and free fatty acid content of the fat of pork, stored under various conditions and subsequently converted to bacon, showed that temperature, method of wrapping, and stage in the conversion to bacon were the most important factors governing the oxidation and hydrolysis of the fat. Of the conditions studied, storage at temperatures of −18° to −23 °C. with an aluminium foil wrapping, followed by thawing in brine or pickle were the most effective in retarding rancidity. The greatest increase in the peroxide oxygen content of the fat occurred during cure, whereas that of free fatty acid increased at a relatively uniform rate throughout the various conversion steps. Smoking had greater antioxidant effect on the fat than pale-drying. Since in all instances the content of free fatty acid was low, spoilage in pork or bacon fat is primarily due to oxidation.

In vivo study of the biosynthesis of long-chain fatty acids using deuterated water

1995 ◽  
Vol 269 (2) ◽  
pp. E247-E252 ◽  
Author(s):  
H. O. Ajie ◽  
M. J. Connor ◽  
W. N. Lee ◽  
S. Bassilian ◽  
E. A. Bergner ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
De Novo ◽  
Chain Elongation ◽  
Deuterated Water ◽  
De Novo Synthesis ◽  
Isotopomer Distribution ◽  
Long Chain ◽  
Mass Isotopomer

To determine the contributions of preexisting fatty acid, de novo synthesis, and chain elongation in long-chain fatty acid (LCFA) synthesis, the synthesis of LCFAs, palmitate (16:0), stearate (18:0), arachidate (20:0), behenate (22:0), and lignocerate (24:0), in the epidermis, liver, and spinal cord was determined using deuterated water and mass isotopomer distribution analysis in hairless mice and Sprague-Dawley rats. Animals were given 4% deuterated water for 5 days or 8 wk in their drinking water. Blood was withdrawn at the end of these times for the determination of deuterium enrichment, and the animals were killed to isolate the various tissues for lipid extraction for the determination of the mass isotopomer distributions. The mass isotopomer distributions in LCFA were incompatible with synthesis from a single pool of primer. The synthesis of palmitate, stearate, arachidate, behenate, and lignocerate followed the expected biochemical pathways for the synthesis of LCFAs. On average, three deuterium atoms were incorporated for every addition of an acetyl unit. The isotopomer distribution resulting from chain elongation and de novo synthesis can be described by the linear combination of two binomial distributions. The proportions of preexisting, chain elongation, and de novo-synthesized fatty acids as a percentage of the total fatty acids were determined using multiple linear regression analysis. Fractional synthesis was found to vary, depending on the tissue type and the fatty acid, from 47 to 87%. A substantial fraction (24-40%) of the newly synthesized molecules was derived from chain elongation of unlabeled (recycled) palmitate.

scholarly journals Evidence for the regulation of guinea-pig heart microsomal phosphatidylcholine-hydrolysing phospholipase A1 by guanosine 5′-[γ-thio]triphosphate

1992 ◽  
Vol 288 (3) ◽  
pp. 965-968 ◽  
Author(s):  
K Badiani ◽  
X Lu ◽  
G Arthur
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Guinea Pig ◽  
Molecular Species ◽  
Inhibitory Effect ◽  
Phospholipase A1 ◽  
Guinea Pig Heart ◽  
Substrate Specificities ◽  
Rate Of Hydrolysis ◽  
Hydrolysis Of

We have recently characterized lysophospholipase A2 activities in guinea-pig heart microsomes and postulated that these enzymes act sequentially with phospholipases A1 to release fatty acids selectively from phosphatidylcholine (PC) and phosphatidylethanolamine, thus providing an alternative route to the phospholipase A2 mode of release. In a further investigation of the postulated pathway, we have characterized the PC-hydrolysing phospholipase A1 in guinea-pig heart microsomes. Our results show that the enzyme may have a preference for substrates with C16:0 over C18:0 at the sn-1 position. In addition, although the enzyme cleaves the sn-1 fatty acid, the rate of hydrolysis of PC substrates with C16:0 at the sn-1 position was influenced by the nature of the fatty acid at the sn-2 position. The order of decreasing preference was C18:2 > C20:4 = C18:1 > C16:0. The hydrolyses of the molecular species were differentially affected by heating at 60 degrees C. An investigation into the effect of nucleotides on the activity of the enzyme showed that guanosine 5′-[gamma-thio]triphosphate (GTP[S]) inhibited the hydrolysis of PC by phospholipase A1 activity, whereas GTP, guanosine 5′-[beta-thio]diphosphate (GDP[S]), GDP, ATP and adenosine 5′-[gamma-thio]triphosphate (ATP[S]) did not affect the activity. The inhibitory effect of GTP[S] on phospholipase A1 activity was blocked by preincubation with GDP[S]. A differential effect of GTP[S] on the hydrolysis of different molecular species was also observed. Taken together, the results of this study suggest the presence of more than one phospholipase A1 in the microsomes with different substrate specificities, which act sequentially with lysophospholipase A2 to release linoleic or arachidonic acid selectively from PC under resting conditions. Upon stimulation and activation of the G-protein, the release of fatty acids would be inhibited.

Effect of insulin on free fatty acid uptake by hepatocytes in the duck

1984 ◽  
Vol 102 (3) ◽  
pp. 381-386 ◽  
Author(s):  
R. Gross ◽  
P. Mialhe
Keyword(s):  
Fatty Acids ◽  
Growth Hormone ◽  
Fatty Acid ◽  
Free Fatty Acid ◽  
Glucose Metabolism ◽  
Free Fatty Acids ◽  
Fatty Acid Uptake ◽  
Acid Uptake ◽  
Low Doses ◽  
Higher Doses

ABSTRACT To elucidate the hypolipacidaemic effect of insulin in ducks, its action on the uptake of free fatty acids (FFA) by duck hepatocytes was determined. At low doses (10 mu./l) insulin stimulated FFA uptake. This effect was not observed with higher doses of insulin (20, 30 and 50 mu./l). Growth hormone at physiological concentrations and corticosterone (14·4 nmol/l) decreased basal activity, probably by reducing glucose metabolism and consequently α-glycerophosphate (α-GP) supply. Insulin was able to reverse the inhibition induced by GH and corticosterone on both FFA uptake and α-GP production. These results therefore suggest that the hypolipacidaemic effect of insulin may be partly mediated by its action on hepatic FFA uptake. J. Endocr. (1984) 102, 381–386

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