Effect Of Distillation Methods And Heat Preservation Of Pipe Between Two Kettles On Volatile Compounds In Cherry Brandy

The quality of brandy is mainly determined by volatile compound, and its content is influenced by distillation methods and equipments. In this study, we used double-kettle distiller to simulate the two classical distillation methods (continuous distillation and batch distillation) to distill cherry brandy. Besides, heat preservation was processed on the heating-pipe between the two kettles of distiller, then distilled cherry brandy with single continuous distillation. During the whole distillation process, we recorded the operations, time points and powers, and the raw brandy was sampled precisely. Then the volatile compounds in raw brandy samples were detected by SPME-GC-MS, together with the general assessment on the brandy aroma content by OAV. Meanwhile, the methanol content in raw brandy that was sampled after heat preservation was assessed was detected by GC. Then, the effect of heat preservation was assessed according to the consumption of energy, cooling water and time during the distillation process. The results were as follows:Distillation methods:a) The content of higher alcohols was greatly decreased in batch distilled brandy, especially,1-hexanol, isobutanol,1-propanol, benzyl alcohol, while hexanol was reduced by 51.0%.b) The content of ethyl ester which presented a pleasant aroma was increased in batch distilled brandy, including ethyl caproate, ethyl caprate, ethyl benzoate. However, the OAV value of isoamyl formate was reduced from 2.38 to below 0.1, after the batch distillation.c) The content of furfural and benzaldehyde which present a baked and almond aroma, was decreased after the batch distillation. And the total carboxide content in was only 54.7% compared with continuous distilled brandy.d) In the continuous distilled brandy, the total content of terpenes was increased 39.4% than the batch distillation, while the total OAV had no obvious difference. However, linalool and nerolidol were increased by 4.1% and 11.1% respectively, after the batch distillation.e) The continuous distilled brandy had better baked and almond aroma, but not pure. After the batch distillation, raw brandy aroma became more complex and pure, with stronger fruity and floral.Heat preservation:a) The higher alcohol (decanol methal, phenylethanol et al) with a pleasant aroma was increased in raw brandy after heat preservation. However, the total higher alcohol content had no significant changes.b) Heat preservation improved the total ester content in raw brandy. The content of ethyl caproate, ethyl caprate, and ethyl benzoate was increased 9.5%,3.5% and 44.6% respectively. The OAV of total esters increased 12.7%.c) The content of nerolidol was reduced to trace amount after heat preservation. On the contrary, the content of geraniol increased by 159.5%, and the OAV of terpenes increased by 16.7%.d) The total carboxide content was reduced by 27.9% after heat preservation, mainly in the decrease of furfural, benzaldehyde, and decanone.e) In conclusion, the raw brandy had better fruity, floral and sweet aroma after heat preservation, and the intensity and purity of aroma was also improved. Besides, heat preservation had no significant effect on the methanol content, which could meet the requirement of national standard for the limit of methanol. The cooling water and energy consumption was reduced by 10.9% and 11.0%, and 11.0% respectively after heat preservation.