American Journal of Enology and Viticulture · 2004 · 134 citations · 0 references
AgricultureEnologyFood ScienceWine AnalysisWine ChemistryWine Quality ControlPhenolic Compound AnalysisPhenolic Compounds In WinePhenolic Profile AnalysisTannin AnalysisWine Composition AnalysisWine Quality AssessmentAntioxidant Activity AssaysAntioxidant PropertiesPhenolic Composition AnalysisPhenolic Content AnalysisPhenolic QuantificationTotal Phenolic ContentVoltammetryWine Phenolic Composition
The substances measured by pigmented tannin assays require clarification. The study compared conventional phenolic assays (Folin‑Ciocalteu, RP‑HPLC, NP‑HPLC, DAC) with newer methods (tannin/polymeric pigment assay, cyclic voltammetry, antioxidant assay) to assess wine phenolic content. Total phenol, monomeric phenol, anthocyanin, and polymeric pigment assays were highly correlated (r > 0.90), and antioxidant activity correlated strongly with total phenol content, indicating consistency across conventional and newer methods.
A variety of phenolic assays were used to evaluate the phenolic content of Californian red and white wines. Conventional methods (Folin-Ciocalteu, RP-HPLC, NP-HPLC, and dimethylaminocinnamaldehyde [DAC] assays) and relatively new methods (tannin and polymeric pigment assay, cyclic voltammetry, and antioxidant assay) were compared. The total phenol contents measured using the Folin-Ciocalteu, RP-HPLC, and cyclic voltammetry methods were strongly correlated (<i>p</i> < 0.001, r > 0.90). Considering assays measuring the monomeric phenols, the flavan-3-ol content measured using the DAC, RP-HPLC, and NP-HPLC methods were correlated (<i>p</i> < 0.001). Anthocyanin content (RP-HPLC) and colored monomer content (NP-HPLC) were also correlated (r = 0.99, <i>p</i> < 0.001). Tannin and polymeric pigment assays were correlated (r > 0.9, <i>p</i> < 0.001) to the high molecular-weight polymer (HMWP) and total polymer content using the NP-HPLC method, but not to the LMWP. The small polymeric pigment (SPP) and large polymeric pigment (LPP) measured using the tannin and polymeric pigment assay were both correlated (r = 0.79, <i>p</i> < 0.001) to the high molecular-weight colored polymers (HMWCP) (NP-HPLC), but neither with the LMWCP. As the sum of SPP and LPP correlated even better with HMWCP (r = 0.89, <i>p</i> < 0.001), it seems that both these are included in the HMWCP measure. The antioxidant activity of wines correlated (<i>p</i> < 0.001) with the total phenol content (using all assays, r > 0.90). The identity of the substances quantified in the pigmented tannin assays need clarification.