Table 4. Contents of volatile compounds in the distilled spirits (25% alcohol) of solid fermented mashes made from different combinations of fermented agents and auxiliary material

Compounds	Concentration (mg/L)
Compounds	A. oryzae (yellow koji) + zeolite	A. luchuensis (white koji) + zeolite	Traditional nuruk (sanseong) + rice husks
Acetaldehyde	578.71±0.65^a	529.74±2.91^a	228.04±1.04^b
Ethyl acetate	41.99±1.73^c	145.98±1.63^b	326.27±4.96^a
Ethyl butyrate	152.76±0.40^a	162.65±0.95^a	124.93±2.63^b
Ethyl hexanoate	ND	ND	6.81±0.42^a
Ethyl lactate	ND	ND	136.75±3.35^a
Ethyl palmitate	ND	ND	ND
Ethyl nonanoate	ND	ND	ND
Acetic acid	19.34±0.40^c	24.12±0.40^b	99.38±3.10^a
Propionic acid	ND	ND	ND
Butyric acid	ND	ND	95.90±3.10^a
Isovaleric acid	ND	ND	5.37±0.19^a
Valeric acid	ND	ND	ND
Hexanoic acid	ND	43.20±0.13^a	44.26±3.49^a
α-Terpineol	ND	ND	10.85±0.03^a
Linalool	ND	ND	ND
Nerol	ND	ND	ND
Geraniol	ND	13.03±0.46^b	99.05±2.28^a
β-Damascenone	ND	ND	ND
1-Butanol	ND	ND	ND
1-Propanol	220.03±0.54^a	ND	164.52±4.62^b
3-Methyl-1-butanol	ND	ND	ND
Methyl mercaptan	ND	ND	426.78±1.36^a
Furfural	86.93±1.11^c	115.39±1.49^b	376.61±5.40^a
Total	1,099.76±4.83^b	1,034.11±7.97^b	2,145.52±32.87^a

Values in the column with different lowercase superscripts are significantly different at p⟨0.05.