เคมี
เอกสารมาตรฐาน
สหรัฐอเมริกา
AOCS
Cd 19-90
2-Thiobarbituric Acid Value, Direct Method
2017
3
665.0288 AOCS 7th ed. 2017-2019 rev. Ref.
DEFINITION The TBA value is defined as the increase of absorbance measured at 530 nm due to the reaction of the equivalent of 1 mg of test sample per 1 mL volume with 2-thiobarbituric acid. Secondary oxidation products of oils and fats react with 2-thiobarbituric acid forming condensation products the absorbance of which is measured at 530 nm, the wavelength of one of their absorption maxima. SCOPE This method permits the direct determination of the 2-thiobarbituric acid value (TBA value) in oils and fats without preliminary isolation of secondary oxidation products. This standard is applicable to animal and vegetable fats and oils, fatty acids and their esters, partial glycol esters, and similar materials.