RT Journal Article
SR Electronic
T1 Comparison of Enzymatic and ISE Methods for Ammonia Measurements in Untreated Red and White Juices and Wines
JF American Journal of Enology and Viticulture
JO Am J Enol Vitic.
FD American Society for Enology and Viticulture
SP 158
OP 162
DO 10.5344/ajev.2002.53.2.158
VO 53
IS 2
A1 Seth B. Turbow
A1 Graham H. Wehmeier
A1 David E. Block
YR 2002
UL http://www.ajevonline.org/content/53/2/158.abstract
AB The use of a standard, commercial enzymatic assay for determination of ammonia in juices and wines, with a focus on red juices and wines, has been investigated. Ammonia standards were prepared in model wine solutions, white juice and wine, and red juice and wine that ranged from 0 to 300 mg/L of added ammonia. Ammonia concentration in all standards was then determined by enzymatic assay and by ion-selective electrode for comparison. Repeatability and linearity of the enzymatic assay were excellent for both red juice and wine with only a simple filtration step as a pretreatment. Replicate measurements had a coefficient of variation of less than 2%, and the correlation coefficients (R) for both juice and wine were greater than 0.99. These results were similar to those found for the ion-selective electrode measurements.Acknowledgment: The authors wish to acknowledge the American Vineyard Foundation for funding this work through the grant, Evaluation of the Influence of Common Viticultural Practices on the Chemical and Sensory Characteristics of Wines.