Effect of Low-Pressure Radio Frequency (RF) Plasma Exposure Time on the Profile of Turmeric (Curcuma longa L.): GC-MS Based Chemometric Evaluation

This study investigated the effects of low-pressure radio frequency plasma (LPRFP) treatment applied at different durations (90 s, 3, 5, 9, and 15 min) on the volatile component profile of powdered turmeric using GC–MS combined with chemometric analysis. A total of 49 volatile compounds were identified, among which artemisia ketone was the most dominant and stable component, accounting for an average of 39.12%. Ten major constituents, including ar-curcumene, α-zingiberene, β-sesquiphellandrene, β-bisabolene, β-caryophyllene, ar-turmerol, himachalene, farnesene, humulene, and turmerol isomers, collectively represented more than 80% of the total volatile profile and exhibited significant variations. Short plasma exposures (90 s and 3 min) preserved the relative proportions of the dominant sesquiterpenes, maintaining chemical stability close to the control samples. In contrast, prolonged treatments (9 and 15 min) caused a marked reduction in the concentrations and peak areas of these compounds, attributed to non-thermal oxidative degradation. Monoterpenes were identified as the most plasma-sensitive group, whereas oxygenated compounds increased significantly with extended treatment, indicating plasma-induced oxidative transformation. Statistical analyses confirmed that plasma duration significantly influenced volatile composition (p < 0.05). A treatment time of 5 min was determined to be optimal for enhancing volatile release while maintaining the structural integrity of key components. Content analysis revealed a clear differentiation among samples depending on the plasma exposure time. Overall, LPRFP emerges as a promising non-thermal technique for modulating turmeric’s volatile profile in a controlled manner, offering potential applications in quality standardization and functional enhancement within the aromatic and phytopharmaceutical industries.