Behaviour of ethyl caproate during the production and distillation of ethyl caproate-rich riceshochu

Abstract

To increase the popularity of rice shochu, a process was developed to produce ethyl caproate-rich rice shochu by adding a cultured broth of a caproic acid-producing bacterial (CAPB) consortium to the fermentation. When the CAPB consortium containing fermented mash was subjected to vacuum distillation, the distillation efficiency of ethyl caproate was up to~300%, while the distillation efficiencies of the other flavour compounds and ethanol were <100%. The behaviour of ethyl caproate during the production and distillation of an ethyl caproate-rich rice shochu was investigated and the results showed that ethyl caproate was synthesized by Saccharomyces cerevisiae during the shochu production process, and that some of the ethyl caproate synthesized was secreted into the medium. Ethyl caproate in the medium evaporated easily and was transferred to the distillate when distilled. The increase in ethyl caproate after distillation was mainly derived from the release of the intracellular ethyl caproate, with negligible input from the chemical esterification of caproic acid and ethanol. During vacuum distillation, although few yeast cells were disrupted, secretion of the intracellular ethyl caproate was more efficient owing to the increase in temperature, allowing the distillation efficiency of ethyl caproate to be >100%.

Isolation and Identification of a High-Yield Ethyl Caproate-Producing Yeast From Daqu and Optimization of Its Fermentation

“…Although the unique taste of strong-flavor Baijiu is the result of the interaction of many flavor substances, ethyl caproate (EC) with its apple-like flavor is the characteristic flavor substance. This compound determines the quality and aroma profile of strong-flavor Baijiu (Chen et al, 2014(Chen et al, , 2016Tan et al, 2016;Song et al, 2020). There is a clear requirement for a certain content of EC (0.40-2.80 g/L for different grades of strong-flavor Baijiu) in the standard of strongflavor Baijiu (China Light Industry Press, and People's Republic of China Professional Standard, 2006).…”

Isolation and characterization of yeast for the production of rice wine with low fusel alcohol content

“…Each sample was centrifuged at 12,000 rpm and 4°C for 5 min (MX-301, Tomy Industry Co. Ltd, Tokyo, Japan). After filtering the supernatant through a 0.2 μm membrane filter (SYT0116, Jinteng, China), the concentrations of FAs and ethanol were measured using gas chromatography (model 353B, GL Sciences, Tokyo, Japan), as previously described for FAs [ 30 ] and ethanol [ 31 ].…”

“…The compounds in the rice wines, including acetaldehyde, n-propyl alcohol, ethyl acetate, isobutyl alcohol, acetal, isoamyl acetate, n-butyl alcohol, isoamyl alcohol, ethyl lactate, ethyl caproate, acetic acid, β-phenethyl acetate, β-phenethyl alcohol and ethanol, were assayed using gas chromatography (model 353B, GL Sciences, Tokyo, Japan), as previously described [ 30 ].…”

“…The influences of the temperature, pH, glucose concentration and ethanol concentration on the selected strain and reference strain (S. cerevisiae NRRL Y-567) were investigated by growth trials. The tested variables were the temperature (20,25,30,35,40,45, and 50˚C), initial pH (5, 5.5, 6, 6.5, 7, 7.5, and 8), initial glucose concentration (10%, 15%, 20%, 25%, 30%, 35%, and 40% (w/v)), and initial ethanol concentration (4%, 6%, 8%, 10%, 12%, 14%, and 16% (v/v)).…”

Optimization of fermentation conditions for production of ethyl caproate in Baijiu using a selected isolate of Saccharomyces cerevisiae

“…This approach was successful with sake, where the EC content was greatly increased by using a S. cerevisiae isolate selected for high yield, thus improving the quality of the final product (Arikawa et al, 2000;Ichikawa et al, 1991;Kuribayashi et al, 2012;Takahashi et al, 2017). In contrast to the work with sake, there has been little research to measure EC yields with S. cerevisiae obtained from various Baijiu production environments, and the reported EC yields for the S. cerevisiae strains tested are low (< 0.5 mg/L) (Tan et al, 2016;Chen et al, 2016). Therefore, to identify a high EC yielding S. cerevisiae strain, the present study analyzed the ability of isolates obtained from different Baijiu production environments to produce EC.…”