Impact of fermentation temperature on the quality and sensory characteristics of imo‐shochu. Issue 4 (18th October 2021)

• Record Type: Journal Article
• Authors: Liu, Genqiao; Serikawa, Juna; Okutsu, Kayu; Yoshizaki, Yumiko; Futagami, Taiki; Tamaki, Hisanori; Takamine, Kazunori
• Is Part Of: Journal of the Institute of Brewing. Volume 127:Issue 4(2021)
• Page Start: 417
• Page End: 423
• Publication Date: 2021-10-18
• Subjects: Fermentation temperature -- Saccharomyces cerevisiae -- higher alcohol -- acetate ester -- GC‐MS; Brewing -- Periodicals; 663.305
• DOI: 10.1002/jib.674
• Languages: English
• ISSNs: 0046-9750

Abstract

Abstract : This study determined the impact of temperature on fermentation and sensory characteristics of imo‐shochu, prepared at a laboratory scale by fermentation and distillation of moromi (a mixture of rice‐koji, sweet potato and water). In accordance with the typical temperature regime used by shochu makers, the maximum temperature of moromi during fermentation was controlled at 25, 32, or 38°C. After distillation, the characteristics of the imo‐shochu were determined by sensory evaluation and gas chromatography–mass spectrometry. In the moromi fermented at 25°C, the yeast population after fermentation was two‐fold larger, but CO2 productivity was 40% lower than when fermented at higher temperatures. Conversely, the concentration of acetic acid and amino acids were highest in the moromi fermented at 38°C. Shochu fermented at 25°C was rated as the fruitiest by sensory evaluation. It contained more esters (phenethyl acetate and ethyl caproate) and more higher alcohols and fatty acids. Shochu fermented at 38°C had the most acidic odour. This was consistent with the higher acetic acid levels in the moromi. Shochu fermented at 32°C had the sweetest and richest taste. Accordingly, fermentation temperature was found to be a critical factor for fermentative quality and flavour characteristics of imo‐shochu. © 2021 The Institute of Brewing & Distilling