Effects of Oak Chip Treatments on Quality of Dry White Wines During Aging

The objective of the research was to evaluate the effect of different oak chip treatments on quality of Longyan dry white wine during aging. Phenolic substances, antioxidant activity and Cu²⁺ reduction force were measured. The results showed that wines treated with French oak chips (6 g/L) had significantly higher contents of total phenols (0.083 mg/mL) and flavonoids (0.063 mg/mL), also the highest total antioxidant capacity (47.853 U/mL) was observed. However the scavenging rate of DPPH free radicals and hydroxyl radical scavenging rate were the highest in samples aged with American oak chips (6 g/L) and Yanshan oak chips (2 g/L), respectively. As for 12 monomer phenols determined by high-performance liquid chromatography, French oak chips can contribute to the formation of monomer phenols, especially the generation of syringaldehyde (15.134 mg/L) and guaiacol (17.345 mg/L). Cu²⁺ reduction ability of wine sample increased with the increase of oak chips content. Correlation analysis revealed that the monomer phenols had a strong correlation with total antioxidant capacity, DPPH radical scavenging rate and hydroxyl radical scavenging rate. Understanding the influence of oak chips on wine properties could aid to lay a theoretical foundation for the effective use of oak chips in wine.