Table 4. Composition of the mash after the second fermentation stage based on the steaming treatment of sweet potatoes during sweet potato soju production

Components		Microbial (white koji)		Enzymatic (amylase+β-glucosidase)
Components		Steamed	Non-steamed	Steamed	Non-steamed
pH		4.04±0.02^1)B	3.96±0.01^C	4.38±0.01^A	3.92±0.01^D
Total acid (citric acid%)		0.57±0.02^A2)	0.48±0.01^C	0.35±0.01^D	0.54±0.01^B
Total amino acid (glycine%)		0.12±0.01^A	0.08±0.01^B	0.06±0.01^C	0.07±0.01^B
Free amino nitrogen (mg/L)		59,937±73.29^A	42,224±35.58^B	23,207±34.24^D	318.12±20.71^C
Soluble solid (°Brix)		9.40±0.06^A	7.60±0.29^C	9.40±0.06^A	8.00±0.17^B
Reducing sugar (%)		3.18±0.05^B	2.73±0.23^BC	2.35±0.04^C	4.60±0.05^A
Alcohol (%)		13.76±0.07^B	10.74±0.07^D	16.10±0.02^A	13.20±0.07^C
Free sugar(mg/L)	Fructose	475.85±6.31^A	15.17±0.75^C	16.81±0.55^C	40.20±9.20^B
	Glucose	2,853.25±126.17^A	ND	ND	2,278.22±22.16^A
	Sucrose	ND³⁾	ND	ND	ND
	Maltose	88.38±3.94^A	95.52±12.08^B	104.33±14.37^B	219.71±50.29^A
	Isomaltose	2,837.42±89.52^A	2,116.72±174.75^B	2,261.21±236.01^B	2,105.64±7.53^B
	Sum	6,254.90±225.94	2,227.41±187.58	2,382.25±250.93	4,643.77±89.18
Enzyme activities (U/mL)	α-Amylase	1.86±0.30^C	7.82±0.44^B	1.57±0.08^C	11.79±0.02^A
Enzyme activities (U/mL)	SP	0.86±0.05^B	1.26±0.02^A	0.72±0.01^C	0.55±0.04^D

All values are mean±SD (n=3).
^A-DMeans with different superscripts in the same row are significantly different at p<0.05 by Duncan’s multiple range test.
ND, not detected.