Table 4. Reducing power of 70% ethanol extracts of grape fruit stem with different drying methods

Samples¹⁾	Concentration (μg/mL)			Positive control²⁾ (50 μg/mL)
Samples¹⁾	50	100	500	AA	BHA	BHT
GFSF	0.316±0.008³⁾^a⁴⁾	0.636±0.008^a	1.933±0.023^a	2.547±0.017^A	2.578±0.019^A	0.514±0.02^B
GFSI	0.312±0.012^a	0.629±0.014^a	1.765±0.010^b
GFSH	0.248±0.005^b	0.621±0.008^a	1.455±0.026^c
GFSS	0.215±0.005^c	0.587±0.004^b	1.200±0.016^d

¹⁾Abbreviations: GFSF, ethanol extract of grape fruit stem with freeze drying; GFSI, ethanol extract of grape fruit stem with infrared drying; GFSH, ethanol extract of grape fruit stem with heat air drying; GFSS, ethanol extract of grape fruit stem with sun drying.
²⁾AA, L-ascorbic acid; BHA, butylated hydroxyanisole; BHT, butylated hydroxytolune.
³⁾Values are means±SD of triplicate determinations.
⁴⁾Different superscripts within a column (a-d) and row (A-B) indicate significant differences (p<0.05).