A Comparative Analysis of Volatile Compounds Extracted From Finger Citron Using Steam Distillation and Cold‐Press Methods

Background Finger citron is a highly appreciated functional food. The volatile oil derived from finger citron is known to contain a range of bioactive compounds that enhance sleep quality, reduce alcohol‐induced liver damage, and improve liver lipid metabolism. However, there have been few comparative studies on the effects of different extraction methods on its volatile organic compounds (VOCs). Objective This study presents a comparative study of the volatile compounds and their antioxidant properties extracted from finger citron using two distinct methods (steam distillation and cold pressing). Materials and Methods In a controlled small laboratory environment, fresh finger citron is sliced before processing. Extract 0.5 kg of prepared finger citron volatile oil through steam distillation within approximately 5 h. Meanwhile, another 0.5 kg of finger citron was pressed and filtered using an oil press operated in cold pressing mode. Before collection, centrifuge the obtained volatile oil for 5 min and filter it. This study employed gas ghromatography–ion mobility spectrometry (GC–IMS) in combination with principal component analysis (PCA), fingerprints, and orthogonal partial least squares–discriminant analysis (OPLS–DA) to examine the differences in volatile profiles from oils extracted by steam distillation and cold pressing. Simultaneously, comparative analysis was conducted on the antioxidant activity using the DPPH free‐radical scavenging assay and the ABTS radical scavenging assay. Result By comparing the results with a reference compound library, this research initially identified 66 VOCs across the two methods, including 13 aldehydes, 13 alcohols, 10 esters, 7 terpenes, 6 ketones, 6 heterocycles, 4 sulfides, 4 hydrocarbons, 2 ethers, and 1 phenol. The findings indicated that the steam distillation technique yielded oil with a higher concentration of aromatic substances, such as (E)‐2‐hexen‐1‐ol, whereas the cold pressing method produced oil that was richer in pharmacologically active compounds, notably geraniol. Further, PCA analysis confirmed that the extraction methods resulted in distinctly different volatile profiles. Additionally, an OPLS–DA model was established, and 40 characteristic volatile components were identified based on variable importance projection (VIP) scores greater than 1. Discussion and Conclusions The results showed that the antioxidant activity of the volatile oil extracted by the cold‐pressing method was stronger than that of the volatile oil extracted by the steam distillation method. This study reveals the effects of two extraction methods, steam distillation and cold pressing, on the volatile components and antioxidant activity of finger citron, providing a scientific basis for optimizing the application of citrus essential oil in functional foods, natural flavors, and related industries using different extraction techniques.