# The Impact of Sulfite Reduction Alternatives with Various Antioxidants on the Quality of Semi-Sweet Wines

## TL;DR

This study explores alternatives to sulfur dioxide in semi-sweet wines to improve quality while reducing chemical use.

## Contribution

A novel combination of antioxidants improves wine quality and reduces sulfur dioxide use by 33.3%.

## Key findings

- Vitamin C treatment increases free radical scavenging by 16.9% compared to controls.
- Combining GSH, Man, and reduced SO2 improves wine aroma, color, and taste.
- GSH and Man delay phenolic degradation and increase aromatic compounds.

## Abstract

This study is designed to identify strategies for substituting or reducing the use of sulfur dioxide (SO2) while improving the quality of semi-sweet wines. Using the ‘Petit Manseng’ semi-sweet wine as the research object, the effects of different concentrations and combinations of glutathione (GSH), mannan (Man), vitamin C (VC), chitosan oligosaccharide (COS), and SO2 were investigated. The results show that under VC treatment, the DPPH free radical scavenging rate of the wine is higher than that of other antioxidant treatments, with the V-1 treatment being 16.9% higher than the CK treatment. The wine treated with 30 mg/L of SO2 has the highest reducing power. After COS treatment, the wine color deepens, making it unsuitable for sweet white wines. GSH and Man can delay the increase in OD240 and the decrease in total phenolic. Man can increase the content of sweet amino acids such as serine. The treatments with man and GSH result in a greater variety of aromatic compounds and higher content of epigallocatechin. The combination treatment of GSH, Man, and SO2 resulted in semi-sweet wines with a bright color, rich aroma, and full-bodied, balanced taste, achieving the best quality indicators and the highest sensory evaluation. This wine exhibits a light yellow color, full body, and a complex, balanced aroma, which are improvements in quality compared to semi-sweet wines with 30 mg/L of SO2 added, and it reduces the use of SO2 by 33.3%. This study shows that adding 5 mg/L of GSH, 5 mg/L of Man, and 20 mg/L of SO2 can significantly improve the antioxidant properties and quality of semi-sweet wines.