Sequential inoculation with Issatchenkia orientalis and Saccharomyces cerevisiae for acid and aroma modulation in Rosa roxburghii wine

Cili ( Rosa roxburghii Tratt.), a fruit renowned for its high vitamin C and abundant polyphenolic contents, presents challenges in wine-making owing to its high malic acid content, which leads to undesirable acidity and a sometimes bitter taste. Although Issatchenkia orientalis has demonstrable potential for malic acid degradation and aroma enhancement, its sequential application with Saccharomyces cerevisiae in high-acid fruit wine fermentation has not been fully investigated. In this study, we examined the influence of sequential inoculation of I. orientalis (M130) and S. cerevisiae (RMS2) at ratios of 5:1 and 10:1 on the physicochemical properties, antioxidant activities, organic acid profiles, and aromatic composition of Cili wine. Fermentations were performed at 20 °C for 15 days, with fermentation kinetics tracked via CO 2 -related weight loss and yeast populations monitored. At the optimal 10:1 ratio, malic acid content was reduced from 21.62 to 11.62 g/L, total phenolics increased, and antioxidant activity enhanced, as indicated by radical scavenging and reducing power assays. Headspace extraction coupled with GC–MS revealed elevated levels of ethyl esters and higher alcohols, contributing to improved aromatic complexity and sensory quality. Multivariate analyses confirmed these enhancements, establishing sequential inoculation as a promising alternative to malolactic fermentation for improving high-acid fruit wines.