Table 4
Reducing powers of 70% ethanol extracts of grape seed prepared with different drying methods

Samples¹⁾	Concentration(μg/mL)			Positive control²⁾(50μg/mL)
Samples¹⁾	50	100	500	AA	BHA	BHT
GSFD	0.142±0.005^a3)	0.370±0.008^ab	1.633±0.035^a	2.547±0.017^A	2.578±0.019^A	0.514±0.02^B
GSIR	0.056±0.009^c	0.353±0.013^b	2.1.097±0.038^c
GSHD	0.079±0.003^b	0.385±0.007^a	1.217±0.019^b
GSSD	0.076±0.008^b	0.366±0.007^b	1.054±0.008^c

¹⁾Abbreviations: GSFD, ethanol extract of grape seed with freeze drying; GSIR, ethanol extract of grape seed with infrared drying; GSHD, ethanol extract of grape seed with heat air drying; GSSD, ethanol extract of grape seed with sun drying.
²⁾AA, L-ascorbic acid; BHA, butylated hydroxyanisole; BHT, butylated hydroxytolune.
³⁾Values are means±SD of triplicate determinations. Different superscripts within a column (a-d) and row (A-B) indicate significant differences (p<0.05).