Effects of the Addition of Fermented Sorghum or Distilled Fermented Sorghum on the Flavor and Quality of Sorghum Spirit

SHUNG-TANG LAI ¹, JIAN-SHING LEE ¹, TUNG-HSI YU ² AND CHI-YUE CHANG ¹ *

^1. Department of Bioindustry Technology, Da-Yeh University, No.168 University Rd., Dacun, Changhua, Taiwan, R.O.C.
^2. Department of Hospitality Management, Hungkuang University, Taiwan, R.O.C.

(Received: December 17, 2010; Accepted: June 9, 2011)

ABSTRACT

This study investigated the use of third time fermented sorghum and distilled fermented sorghum for the production of sorghum spirits made by solid fermentation and solid distillation. The results indicated that higher yield of alcohol was obtained in groups with 5%, 10% and 15% fermented sorghum addition, slightly higher than that of the control group. With regard to distilled fermented sorghum, the alcohol yields of groups with 5%, 10%, 15% and 20% distilled fermented sorghum addition were higher than that of the control group. The group with 20% distilled fermented sorghum produced the best results. There was no significant difference in acidity among all of the experimental groups. Groups with fermented sorghum or distilled fermented sorghum had higher levels of total esters than that of the control group, indicating that the addition of either fermented sorghum or distilled fermented sorghum contributes to the increase of fragrance-producing esters in sorghum spirits. Flavor tests showed that spirits produced by adding 5% fermented sorghum had a stronger fragrance and better taste than those of the control group. Spirits produced by adding 5 - 20% distilled fermented sorghum also had better taste and aroma than those of the control group spirits. These results indicated that addition of   5 - 20% distilled fermented sorghum to the newly cooked sorghum improved the quality of the produced sorghum spirits. The major fragrance-producing components found in the sorghum spirits were ethyl acetate and ethyl lactate. Other fragrance-producing components include acetaldehyde, iso-butyraldehyde, 2-butanol, n-propanol, iso-butanol, n-butanol, 2-methyl-1-butanol, 3-methyl-1-butanol, ethyl succinate and 2-phenyl ethanol. The addition of fermented sorghum to the newly cooked sorghum was successful in increasing both the higher alcohol (n-propanol, 2-butanol, iso-butanol, n-butanol, 2-methyl-1-butanol and 3-methyl-1-butanol) yield and fragrance. In addition, spirits prepared by adding 5% fermented sorghum had the best proportion of ethyl acetate and ethyl lactate; they also produced a mild fragrance. The overall taste performance of these spirits was better than those of spirits with 10%, 15% or 20% fermented sorghum, or of the control group spirits. Furthermore, the higher alcohol content and ethyl lactate did not vary significantly among the experimental groups with 5 - 20% fermented sorghum. Compared to the control group, groups with 5, 10, 15 and 20% distilled fermented sorghum addition had better values in higher alcohol content as well as the proportion of ethyl acetate and ethyl lactate.

Key words: sorghum spirits, fermented sorghum, distilled fermented sorghum, solid fermentation, solid distillation