scholarly journals A New Colorimetric Method for the Determination of Free Fatty Acids in Milk Fat

1942 ◽  
Vol 25 (8) ◽  
pp. 659-661 ◽  
Author(s):  
Vladimir N. Krukovsky ◽  
Georges Knaysi
Keyword(s):  
Fatty Acids ◽  
Free Fatty Acids ◽  
Milk Fat ◽  
Colorimetric Method

scholarly journals Method for the Determination of the Free Fatty Acids of Milk Fat

1963 ◽  
Vol 46 (12) ◽  
pp. 1342-1347 ◽  
Author(s):  
D.D. Bills ◽  
L.L. Khatri ◽  
E.A. Day
Keyword(s):  
Fatty Acids ◽  
Free Fatty Acids ◽  
Milk Fat

A New Colorimetric Method for the Determination of Free Fatty Acids with Acyl-CoA Synthetase and Acyl-CoA Oxidase1

1981 ◽  
Vol 89 (6) ◽  
pp. 1799-1803 ◽  
Author(s):  
Kohei HOSAKA ◽  
Toshiro KIKUCHI ◽  
Noboru MITSUHIDA ◽  
Akihiko KAWAGUCHI
Keyword(s):  
Fatty Acids ◽  
Free Fatty Acids ◽  
Colorimetric Method

710. The determination of free fatty acids in milk

1958 ◽  
Vol 25 (2) ◽  
pp. 221-227 ◽  
Author(s):  
Dawn R. Perrin ◽  
D. D. Perrin
Keyword(s):  
Fatty Acids ◽  
Molecular Weight ◽  
Free Fatty Acids ◽  
Milk Fat ◽  
Small Samples ◽  
Titration Method ◽  
Fresh Milk ◽  
Lactic Acids ◽  
Accurate Indicator

An extraction-titration method is described for the determination of free fatty acids in small samples of fresh milk.Recoveries of fatty acids added to milk ranged from 63% for butyric acid to 97% for stearic acid. For a composite sample approximating milk fat in fatty acid composition the recovery was 83%.Interference from citric and lactic acids was not significant for reasonably fresh samples.The method gives a higher recovery of the lower molecular weight fatty acids than is possible by earlier methods.For titrating very dilute solutions of fatty acids α-naphtholphthalein was shown to be a more accurate indicator than phenolphthalein; it also provides a better defined endpoint.

scholarly journals Evaluation of development in indirect determination of milk fat free fatty acids in Czech Republic

2013 ◽  
Vol 61 (6) ◽  
pp. 1669-1679 ◽  
Author(s):  
Oto Hanuš ◽  
Eva Samková ◽  
Jan Říha ◽  
Marcela Vyletělová Klimešová ◽  
Petr Roubal
Keyword(s):  
Fatty Acids ◽  
Free Fatty Acids ◽  
Milk Fat ◽  
Raw Milk ◽  
Important Indicator ◽  
Indirect Determination ◽  
Milk Samples ◽  
Bulk Milk ◽  
Instrumental Values

Free fatty acids (FFAs) in fat are important indicator of raw milk quality. Result reliability of FFAs is important. Aim was to verify MIR–FT (mid infrared spectroscopy with Fourier’s transformations) method for its calibration to determine FFAs, time stability of MIR–FT FFA calibration and calibration levelling in laboratory networks. Reference (RE) milk samples (1 set = 8) were prepared according to CSN 57 0533 (FFAs in mmol.100g−1 of fat). MIR–FT instruments were: 1 LactoScope FTIR (DE); 2 Bentley FTS (BE); 2 MilkoScan FT 6000 (FO). 3 calibrations of MIR–FT (5) in 3 laboratories were performed. Bulk milk samples came from 4 herds and 2 breeds. These 4 samples were used for calibration in native and modified form. Modification increased FFAs by cca 100%. Calibration set had 8 samples. 1 between calibration interval was checked monthly by proficiency testing (PT). PT set had 10 samples. 5 samples were with native milk and 5 had modified fat content, lower and higher. Maximal value of difference variability for calibration quality validation is x (sd of difference MIR–FT and RE) plus 1.64 multiple of sd (on 95% level), 1.0613 mmol.100g−1. Mean validation correlation coefficient (r) between MIR–FT and RE results was 0.802 ± 0.082 (P < 0.001), from 0.666 to 0.945. Minimal value at calibration is x minus 1.64 multiple of sd (0.668). Correlations between MIR–FT results were higher by 8.4% (0.869 (P < 0.001) > 0.802). Example PT with 10 and 5 milk samples had similar results of r 0.887 and 0.953 (P < 0.001 and P < 0.05). There is possibility to construct a levelling programme for calibrated instruments. Some equation between PT reference and instrumental values could correct MIR–FT results for their better comparability.

Colorimetric Microdetermination of Free Fatty Acids

1973 ◽  
Vol 19 (4) ◽  
pp. 419-424 ◽  
Author(s):  
Felix G Soloni ◽  
Laura C Sardina
Keyword(s):  
Fatty Acids ◽  
Oxalic Acid ◽  
Free Fatty Acids ◽  
Filter Paper ◽  
Normal Values ◽  
Colorimetric Method ◽  
Reference Method ◽  
Chloroform Extract ◽  
Related Difference

Abstract A colorimetric method for determination of free fatty acids has been developed, based on the estimation of copper in a chloroform extract of their cupric salts with oxalic acid bis-(cyclohexylidenehydrazide). Contamination with inorganic copper during extraction is practically eliminated by using filter-paper pads. Specificity and interferences are discussed. Recoveries average 101.1%. Normal values are 10.0 ± 8.2 mg/dl (0.390 ± 0.320 mmol/liter), with no statistically significant sex-related difference. Correlation with the reference method of Dole and Meinertz [J. Biol. Chem. 235, 2595 (1960)] is 0.954. Ten samples can be measured in about 45 min.

Automated Colorimetric Determination of Free Fatty Acids in Biologic Fluids

1967 ◽  
Vol 13 (9) ◽  
pp. 744-751 ◽  
Author(s):  
C Dalton ◽  
C Kowalski
Keyword(s):  
Fatty Acids ◽  
Free Fatty Acids ◽  
Colorimetric Method ◽  
Extraction Procedure ◽  
Automated Analysis ◽  
Colorimetric Determination ◽  
Direct Extraction

Abstract For the routine determination of free fatty acids (FFA) the authors recommend a modification of the automated colorimetric method of Antonis (1) using the extraction procedure of ltaya and Ui (2). This direct extraction and automated analysis shows good correlation with Trout's (3) modification of Dole's (4) titrimetric procedure.

Enzymic determination of free fatty acids in serum.

1980 ◽  
Vol 26 (11) ◽  
pp. 1540-1543 ◽  
Author(s):  
H Okabe ◽  
Y Uji ◽  
K Nagashima ◽  
A Noma
Keyword(s):  
Fatty Acids ◽  
Free Fatty Acids ◽  
Colorimetric Method ◽  
Simultaneous Production ◽  
Production Of Hydrogen ◽  
Standard Solution ◽  
Acyl Coa Oxidase ◽  
Assay Precision ◽  
Mean Concentration

Abstract We describe the enzymic determination of free fatty acids in serum with use of acyl-CoA synthetase (EC l.2.1.3), acyl-CoA oxidase (no EC no. assigned) and peroxidase (EC 1.11.1.7). The free fatty acids are activated by acyl-CoA synthetase in the presence of ATP and coenzyme A. The acyl-CoA formed is oxidized by acyl-CoA oxidase to enoyl-CoA with simultaneous production of hydrogen peroxide, which is oxidatively coupled with 4-amino-antipyrine and 2,4-dibromphenol in the presence of peroxidase to yield a product that absorbs maximally at 505 nm. Standard curves prepared with various kinds of fatty acids are linear to at least 2.0 mmol/L and are practically congruent. Ascorbic acid or bilirubin interferes slightly. Results by the present method correlate well with those by the colorimetric method involving 2-(2-thiozolylazo)-p-cresol (r = 0.98). Replicate analyses of standard solution and of two kinds of control sera demonstrated the following between-assay precision: mean absorbance 0.224 (SD 0.002), CV 0.85%; mean concentration, 326 (SD 7.3) and 1076 (SD 22.7) mumol/L, CV 2.24 and 2.11%, respectively.

Sign in / Sign up

Export Citation Format

Share Document