Collaborative Study of a Method for Determination of MVIalic Acid in Grapes and Grape Products

1969 ◽  
Vol 52 (6) ◽  
pp. 1153-1154
Author(s):  
E Fernandez-Flores ◽  
Arthur R Johnson ◽  
Victor H Blomquist
Keyword(s):  
Malic Acid ◽  
Collaborative Study ◽  
Grape Juice ◽  
Potassium Acetate

Abstract The polarimetric method for the determination of l-malic acid in grape juice and grape products has been further modified by increasing the amount of potassium acetate used, adjusting the alcohol wash concentration, and utilizing a more efficient filtration for the removal of interfering tartrate salts. Collaborators reported acceptable results and no difficulties were reported. It is recommended that the method as modified be adopted as official first action for the determination of l-malic acid in grape juice and grape products.

scholarly journals Determination of D-Malic Acid in Apple Juice by Liquid Chromatography: Collaborative Study

1996 ◽  
Vol 79 (1) ◽  
pp. 50-54 ◽  
Author(s):  
Thomas A Eisele ◽  
K Adadevoh ◽  
G Anderson ◽  
A Brause ◽  
D Briesmeister ◽  
...  
Keyword(s):  
Malic Acid ◽  
Apple Juice ◽  
Copper Acetate ◽  
Collaborative Study ◽  
Reversed Phase ◽  
Uv Detector ◽  
Paired Samples ◽  
Study Results ◽  
Liquid Chromatographic

Abstract Eleven laboratories collaboratively studied a liquid chromatographic (LC) method for determination of D-malic acid in apple juice. The mobile phase consisted of 16 mM L-valine and 8 mM copper acetate adjusted to pH 5.5 with NaOH. The UV detector was set at 330 nm, and a single reversed-phase LC column was used. Seven paired samples containing various amounts of D-malic acid ranging from 0 to 188 mg/100 mL of 12 Brix pasteurized apple juice were tested by each collaborator. Repeatability and reproducibility coefficients of variation ranged from 1.0 to 3.5% and 7.7 to 11.7%, respectively, within the range of 26 to 188 mg D-malic acid/100 mL of 12 Brix apple juice. The collabora tive study results demonstrated that the method could quantitate the economic adulteration of ap ple juice with DL-malic acid at lower levels than those reported with previous methods. The LC method for determination of D-malic acid in apple juice has been adopted first action by AOAC INTERNATIONAL.

Liquid Chromatographic Method for Determination of Glycerol in Wine and Grape Juice: Collaborative Study

1992 ◽  
Vol 75 (3) ◽  
pp. 379-383 ◽  
Author(s):  
Arthur Caputi ◽  
Eric Christensen ◽  
Nancy Biedenweg ◽  
Susan Miller
Keyword(s):  
Chromatographic Method ◽  
Collaborative Study ◽  
Grape Juice ◽  
External Standard Method ◽  
Liquid Chromatographic Method ◽  
Relative Standard ◽  
External Standard ◽  
Standard Deviations ◽  
Liquid Chromatographic

Abstract An Ion-exchange liquid chromatographic method for the determination of glycerol in wine, white grape juice, and pink grape juice was collaboratively studied by 8 laboratories. Eight wine types and 12 juice samples were provided to each collaborator. Using a strong cation column, blind duplicates and standards were analyzed by an external standard method. Separate statistical evaluations were run on wine, white grape juice, and pink grape juice data. The averages of the relative standard deviations for repeatability, excluding outlying results, were 1.25% for the wine samples, 7.32% for the white grape juice samples, and 8.63% for the pink grape juice samples. The averages of the relative standard deviations for reproducibility, excluding outlying results, were 2.79% for the wine samples, 16.97% for the white grape juice samples, and 19.10% for the pink grape juice samples. The method has been adopted first action by AOAC International.

Determination of Tartaric Acid and the Sum of Malic and Citric Acids in Grape Juices by Potentiometric Titration

1988 ◽  
Vol 71 (5) ◽  
pp. 1028-1032
Author(s):  
Oswaldo E S Godinho ◽  
Nilson E Desouza ◽  
Luiz M Aleixo ◽  
Ari U Ivaska
Keyword(s):  
Citric Acid ◽  
Tartaric Acid ◽  
Potentiometric Titration ◽  
Malic Acid ◽  
Grape Juice ◽  
Algebraic Method ◽  
The Individual ◽  
Grape Juices ◽  
Linear Algebraic Method

Abstract Application of a linear algebraic method to the potentiometric titration of a mixture of tartaric and malic acids makes it possible to determine the individual concentrations of both acids in the same sample. These 2 acids have also been determined in grape juice free of citric acid after their separation from the juice matrix by precipitation as barium salts, followed by selective solubilization. It is also possible to determine tartaric acid and the sum of malic acid and citric acid in grape juice when the latter is present.

Interlaboratory Variability of Methods Used for Detection of Economic Adulteration in Apple Juice

1985 ◽  
Vol 68 (4) ◽  
pp. 672-676 ◽  
Author(s):  
John Zyren ◽  
Edgar R Elkins
Keyword(s):  
Malic Acid ◽  
Apple Juice ◽  
Collaborative Study ◽  
Great Promise ◽  
Interlaboratory Variability ◽  
Acid Ratio ◽  
Coefficients Of Variation ◽  
A Minor ◽  
Important Test

Abstract Thirteen laboratories participated in a study to determine the interlaboratory variability of 4 methods used to detect economic adulteration in apple juice. The methods included the determination of individual sugars, 5-(hydroxymethyl)-2-furaldehyde, chlorogenic acid, organic acids, and L-malic acid. The coefficients of variation found depended on the method and level of analyte, but were often 5% or less. At this point, the most important test for detecting economic adulteration is the total malic/L-malic acid ratio. Any ratio of 0.9 or less would indicate a nonauthentic sample. The 0.9 ratio represents an addition of 20% synthetic malic acid in the unknown juice sample. A 0.75 ratio would indicate 50% adulteration, while a 0.5 ratio would indicate a totally synthetic juice. Fumaric acid, a minor contaminant in synthetically produced malic acid, shows great promise as an indicator of economic adulteration. The results support the view that the methods are now ready for AOAC collaborative study.

Collaborative Study of the Determination of l-Malic Acid in Lemon Juice

1966 ◽  
Vol 49 (3) ◽  
pp. 621-623
Author(s):  
Henry Yokoyama
Keyword(s):  
Malic Acid ◽  
Acid Content ◽  
Collaborative Study ◽  
Lemon Juice ◽  
Collaborative Studies

Abstract Additional collaborative studies were conducted on the l-malic acid content of lemon juice. Results were accurate and precise; the method is recommended for adoption as official, first action.

scholarly journals New enzymatic method for estimating fumaric acid in wines

OENO One ◽  
2021 ◽  
Vol 55 (3) ◽  
pp. 273-281
Author(s):  
Daniel Fernández-Vázquez ◽  
Nicolas Rozès ◽  
Joan Miquel Canals ◽  
Albert Bordons ◽  
Cristina Reguant ◽  
...  
Keyword(s):  
Fumaric Acid ◽  
Malic Acid ◽  
Red Wine ◽  
Grape Juice ◽  
White Wine ◽  
Hplc Method ◽  
Enzymatic Method ◽  
Synthetic Solution ◽  
Very High

This work aims to develop a new enzymatic method for analysing fumaric acid in wines. Fumaric acid is a very effective lactic acid bacteria inhibitor that is widely used in the food industry as an additive (E297). Using it to inhibit malolactic fermentation has recently been authorized by the International Organisation of Vine and Wine (OIV). However, the official analytical method for fumaric acid involves the classical HPLC method for organic acids, which is overly complicated for use in wineries. This research proposes a very simple and efficient enzymatic method that allows the simultaneous determination of L-malic acid and fumaric acid. The method uses a commercial enzymatic kit for L-malic acid and adds a supplementary step in which the fumarase enzyme is added to transform fumaric acid into L-malic acid. The results obtained show that this method could be used in different media (synthetic solution, white wine, red wine and white grape juice). This article also proposes a modification of the enzymatic method to be applied when the L-malic acid concentration of the sample is very high.

Sign in / Sign up

Export Citation Format

Share Document