# Effects of Different Extraction Methods on Vanilla Aroma
###### Abstract  
To establish the analytic conditions for examining the aroma quality of vanilla pods, we compared different extraction methods and identified a suitable option. We utilized headspace solid-phase microextraction (HS-SPME), steam distillation (SD), simultaneous steam distillation (SDE) and alcoholic extraction combined with gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) to identify volatile components of vanilla pods. A total of 84 volatile compounds were identified in this experiment, of which SDE could identify the most volatile compounds, with a total of 51 species, followed by HS-SPME, with a total of 28 species. Ten volatile compounds were identified by extraction with a minimum of 35% alcohol. HS-SPME extraction provided the highest total aroma peak areas, and the peak areas of aldehydes, furans, alcohols, monoterenes and phenols compounds were several times higher than those of the other extraction methods. The results showed that the two technologies, SDE and HS-SPME, could be used together to facilitate analysis of vanilla pods aroma. vanilla; GC-MS; volatile components; HS-SPME; SDE +
Footnote †: journal: molecules  
0000-0001-9991-3300-3300][PERSON]. [PERSON] 00000-0002-0002-0002-0002-0003][PERSON] 0000-0002-0002-0003-0002-0003-0003-0003-0003  
Simultaneous steam distillation solvent extraction, a traditional extraction technique that is widely used to analyze volatile compounds [4], is a technique that combines solvent and steam distillation extraction, with better extraction efficiency than the former [6]. However, for many analyses, SDE is labor intensive, lacks sensitivity [7], requires large sample volumes, is time-consuming [8], and may raise concerns about solvent residues. In addition, under high-temperature extraction, some volatile compounds are easily hydrolyzed, thermally cracked or lost [7]. [PERSON] et al. [4] also found that SDE is less sensitive to trace components. Nevertheless, the reproducibility of SDE is high, so SDE is the preferred choice for the quantitative analysis of volatiles. Traditional methods of extracting volatile components are often time-consuming and prone to the loss or degradation of volatile components [9], in addition to low yields and the use of large amounts of solvents [1]. Therefore, modern scientists are devoted to finding extraction techniques that use low or even no solvent, thereby reducing the residual amount of harmful solvents in natural extracts [10]. SPME is a relatively new extraction technique [8] that is simpler than traditional methods [11], fast, solvent-free [7], environmentally friendly [3], does not thermally degrade or hydrolyze samples [4] and inexpensive [2]. Additional advantages without the need for time-consuming sample preparation are still needed [12], as well as strategies to reduce the harm caused by solvents to humans and the environment. Therefore, SPME has been applied in many fields, including agriculture, medicine [13], clinical testing, spice, food and environmental science [14]. This method has been demonstrated to rapidly extract volatile organic compounds (VOCs), and it is often used in GC and high-performance liquid chromatography (HPLC) to analyze the composition of complex volatile compounds in plants [9; 11]. However, SPME also has disadvantages, which can lead to inaccurate quantification due to the adsorption competition of different volatile components. In addition, it has poor sensitivity and therefore cannot detect trace components [3]. Steam distillation extraction has been used to extract volatile compounds from medicinal plants [8] and is a traditional extraction technique used to separate essential oils from plants [15]. The principle is to use boiling water or steam to separate lower boiling volatile compounds from plant raw materials [16]. These water vapors and volatile oils are condensed through the condensing device and are called hydrosol and essential oil, respectively.