Table 1 Color difference values of black ginger powder

Color value	Steaming and drying step
	0	1	2	3	4	5	6	7	8	9
	L*a	85.65±0.33	75.09±0.26	68.66±0.20	68.85±0.16	59.17±0.59	59.19±0.13	57.50±0.20	57.47±0.19	57.30±0.62	56.91±0.25
a*b	-1.51±0.03	3.69±0.08	6.00±0.08	6.03±0.04	6.93±0.04	7.07±0.02	7.12±0.02	7.21±0.03	7.34±0.08	7.21±0.04
b*c	26.99±0.20	23.96±0.16	22.35±0.21	22.42±0.12	18.33±0.12	18.00±0.08	17.25±0.08	17.15±0.05	17.48±0.13	16.69±0.06
△Ed	29.49±0.05	33.04±0.25	36.98±0.28	36.87±0.20	43.05±0.59	42.92±0.13	44.14±0.20	44.15±0.20	44.44±0.63	44.49±0.25

Values are the average of three replicates per treatment ± SD.
Value of lightness (white + 100 ↔ 0 black).
Value of redness (red +100 ↔ -80 green).
Value of yellowness (yellow +70 ↔ -80 blue).
Overall color difference ( ΔL 2 +Δa 2 +Δ b 2 )