Antioxidant assessment of a glutathione-rich extract obtained from electroporated cells of Saccharomyces cerevisiae in white grape must

Sulfur dioxide (SO 2 ) is widely used in winemaking for its antioxidant and antimicrobial properties, but its application is increasingly questioned due to health concerns and regulatory restrictions. Glutathione (GSH) has emerged as a promising alternative, effectively preventing oxidative browning and preserving key aroma compounds. This study presents an integrated approach to enhance GSH production and extraction from Saccharomyces cerevisiae , combining amino acid supplementation and Pulsed Electric Fields (PEF) technology. Optimal supplementation with glutamic acid, cysteine, and glycine at 30 h increased intracellular GSH accumulation by 53 % (yielding 443 ± 7.9 mg GSH /L of culture). PEF treatment (20 kV/cm, 150 μs, 153.3 kJ/kg) achieved >90 % membrane permeabilization, allowing the recovery of 66 % of intracellular GSH. The lyophilized extract contained 51.2 ± 1.32 mg GSH/g, with a GSH/GSSG ratio of 19.2, exceeding the OIV standard for inactivated yeast preparations. The PEF-GSH extract exhibited higher antioxidant capacity than a commercial inactivated yeast product in aqueous assays, nonetheless, both showed comparable efficacy in mitigating oxidative browning in grape must. The combination of GSH-derived extracts with SO 2 enabled a 50 % reduction in required sulfite concentration while maintaining must stability. Additionally, the PEF-GSH extract exhibited lower high-molecular-weight protein content, minimizing turbidity risk and enhancing its post-fermentation applicability. These findings support PEF-assisted extraction as an efficient strategy for producing GSH-rich extracts, offering a viable alternative to reduce SO 2 use in winemaking. • Amino acids supplementation + PEF extraction enabled a GSH-rich extract from yeast. • PEF-GSH extract showed comparable antioxidant power in must to commercial product. • PEF-GSH extract cut SO₂ dose by 50 % while preserving must oxidative stability.