Determination of the Phenolic Content of Some French-American Hybrid White Wines Using Ultraviolet Spectroscopy

Abstract

The ultraviolet spectra of several white French-American hybrid regional wines were used to determine their phenolic content. The calculation of the flavonoid and nonflavonoid content was based on the difference in the absorbance at 280 and 320 nm of the wine sample before and after fining with polyvinylpolypyrrolidone (PVPP). The ultraviolet spectra of 18 phenols were also obtained in order to determine the efficiency of PVPP as an adsorbing agent and the appropriateness of the proposed analytical wavelengths. After considering the wide variation in the efficiency with which PVPP adsorbs individual phenols, the selection of the analytical wavelengths misclassifying certain phenols, and the high proportion of wines found to contain the interfering additive sorbate, it can be concluded that the applicability of the method may be questionable.