RT Journal Article
SR Electronic
T1 Enzymatic Assay for Malic Acid and Malo-Lactic Fermentations
JF American Journal of Enology and Viticulture
JO Am J Enol Vitic.
FD American Society for Enology and Viticulture
SP 212
OP 215
DO 10.5344/ajev.1980.31.3.212
VO 31
IS 3
A1 Leo P. McCloskey
YR 1980
UL http://www.ajevonline.org/content/31/3/212.abstract
AB A rapid enzymatic method for the determination of malic acid in grape juice and wine is presented which is designed for monitoring malo-lactic fermentations in the said liquids. The results allow for the calculation of malate levels and therefore of malo-lactic fermentation rates. This particular enzymic assay for malic acid uses malate dehydrogenase and glutamate oxaloacetate transaminase for accelerating the main enzymic assay reaction catalyzed by malate dehydrogenase. The assay reactions utilize the photometric determination of NADH at 340 nm. In five minutes the analyst can detect up to 2000 mg/L malate and in seven minutes up to 4000 mg/L. Essentially 100% of the malic acid is recovered with a standard deviation of better than 35 ppm.