Expert Review Panel for Kombucha Tea
AOAC SPDS ERP REVIEW: MAIN FORM
Submission Date
2017-09-12 15:56:34
Name
SNEH BHANDARI
SNEH.BHANDARI@MXNS.COM
Organization
Merieux NutriSciences
Title of Method
Enzymatic method for measurement of Ethanol in Kombucha
AOAC Candidate Method Number (e.g. ALN-01)
KOM-06
Applicable SMPR
2016.001
Summary:
Enzymatic method for measurement of ethanol in Kombucha. The method is based on Megazyme’s Ethanol-assay kit (K-ETOH).
The quantification of ethanol requires two enzyme reactions; in the first reaction catalysed by alcohol dehydrogenase (ADH), ethanol is oxidised to acetaldehyde by nicotinamide-adenine dinucleotide (NAD+) (1) Ethanol + NAD+ ADH ------------ acetaldehyde + NADH + H+ However, since the equilibrium of reaction (1) lies in favour of ethanol and NAD+, a further reaction is required to “trap” the products. This is achieved by the quantitative oxidation of acetaldehyde to acetic acid in the presence of aldehyde dehydrogenase (Al-DH) and NAD+. (2) Acetaldehyde + NAD+ + H2O Al-DH----------------- acetic acid + NADH + H+ The amount of NADH formed in this reaction pathway is stoichiometric with twice the amount of ethanol. It is the NADH which is measured by the increase in absorbance at 340 nm.
1. Does the applicability of the method support the applicability of the SMPR? If not, please explain what is missing. 2. Does the analytical technique(s) used in the method meet the SMPR? If not, please specify how it differs from what is stated in the SMPR. 3. Are the definitions specified in the SMPR used and applied appropriately in the method? If no, please indicate how the terms are used.
Yes
Yes
Yes
Made with FlippingBook - Online magazine maker