VARIATIONS OF FLAVOR SUBSTANCES IN DISTILLATION PROCESS OF CHINESE LUZHOU‐FLAVOR LIQUOR
To investigate the variations of flavor substances in distillation process of Chinese Luzhou‐flavor liquor, systematic experiments were carried out in an industrial‐scale experimental distiller. Distillate samples were collected continuously throughout the whole distillation process and analyzed by gas chromatography and sensory evaluation. The results show that the compositions and variations of flavor substances mainly depend on their physical and chemical properties. The flavor substances with low boiling point, such as ethanol, acetaldehyde, ethyl format and ethyl acetate, are vaporized quickly and therefore have high contents in the distillate obtained in the early stage of distillation. The flavor substances with high boiling points enter into distillate mainly by extraction and, hence, their variations depend on the dissolving properties. The alcohol‐soluble substances, such as ethyl hexanoate, ethyl butanoic and so on, are distilled out mainly in the early stage of distillation, and their extraction rates decrease as the distillation process proceeds, while the water‐soluble substances, such as organic acids, ethyl lactate and so on, are mainly present in the latter‐stage distillate and the extraction rates increase as the process proceeds. Variations of methanol and furfural were found irregular and the reasons for this irregularity were analyzed. Sensory quality of distillate declines as the distillation process proceeds.
Chinese liquor has been a traditional art continuing for thousands of years, but the distillation operation almost holds its way of ancient time and few studies about it have been conducted, so that the understanding of distillation process is largely limited to intuition. Variations of flavor substances during distillation process will certainly contribute to the understanding of distillation mechanism and the optimization of distillation operation. The remarkable differences of distillate qualities found in different distillation stages provide an experimental base for collecting liquors with different distillate qualities. The findings that the high quality distillate is produced in early distillation stage indicate the necessity to overcome the vapor‐overflow phenomenon, which occurs usually in the early stage of distillation and causes a lot of loss of high quality liquor. Theoretically, this work will provide the experimental base and testifying data for the modeling of multicomponents mass transfer in liquor distillation process through a packed bed.
Document Type: Research Article
Publication date: April 1, 2012