Characterization of Volatile and Semi-Volatile Compounds in Chinese Rice Wines by Headspace Solid Phase Microextraction Followed by Gas Chromatography-Mass Spectrometry

Abstract

The volatile and semi-volatile compounds of Chinese rice wines were extracted by headspace solid phase microextraction (HS-SPME) and analyzed by gas chromatography-mass spectrum (GC-MS). The original Chinese rice wine samples were diluted with deionized water to a final concentration of 6% (v/v) ethanol and then extracted by HS-SPME. The samples were pre-equilibrated at 50°C for 15 min and extracted with stirring at the same temperature for 45 min prior to injection into a GC-MS. A total of 97 volatile and semi-volatile compounds were identified from ten Chinese typical rice wine samples, including 13 alcohols, 8 acids, 28 esters, 4 aldehydes and ketones, 17 aromatic compounds, 3 lactones, 6 phenols, 3 sulphides, 9 furans and 6 nitrogen-containing compounds, of which, 39 compounds were firstly reported in Chinese rice wine. By stepwise linear discrimination analysis, the ten Chinese rice wine samples could be classified into three groups according to the production area, and in particular, the production technologies.

Changes in Volatile Compounds of Chinese Rice Wine Wheat Qu During Fermentation and Storage

“…Among all of the aromatic compounds examined, 1,2,3-trimethoxybenzene and 4-ethenyl-1,2-methoxybenzene were identified only in wheat Qu and not in wheat. Benzaldehyde, phenylacetaldehyde, benzyl alcohol, ethyl benzoate, acetophenone, 1,2-dimethoxybenzene, and 2-phenylethanol, which were detected in the wheat Qu throughout all fermentations and storage stages studied, were also detected in Chinese rice wine 18 . The compound 1,2,3-trimethoxybenzene, which is associated with smoke and musty odors, presented a higher concentration on the fourth day of fermentation.…”

“…A total of 58 volatile compounds were identified and measured in the wheat Qu samples including 11 alcohols, 6 acids, 3 esters, 7 ketones, 5 aldehydes, 9 aromatics, 1 lactone, 4 phenols, 2 sulphides, 3 furans, 4 nitrogen-containing compounds, and 3 terpenes. Most of these compounds have been previously detected in Chinese rice wine 18 .…”

“…Analysis of the volatile compounds was performed using HS-SPME coupled with a GC-MS according to the procedure described by Luo et al 18 with modifications. The volatile compounds of wheat Qu were extracted using a 50/30 µm divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) fiber (Supelco, Inc., Bellefonte, PA).…”

“…Data were collected in total ion mode for all mixed standards and samples. Semi-quantitative data of the volatile compounds were acquired according to the method described by Luo et al with the following formula 18 :…”

“…The compound 1,2,3-trimethoxybenzene, which is associated with smoke and musty odors, presented a higher concentration on the fourth day of fermentation. The compound 2-phenylethanol, which contributes to rosy and honey aromas and is important in wheat Qu, also had the highest concentration in the Chinese rice wine 18 .…”