Effect of Solar Drying and Vinegar Pretreatment on the Antioxidant Properties and Bioactive Compounds of Sliced Ginger

Table 1

Antioxidant activity of ginger rhizome at an extract concentration of 100 μg/ml on dry basis (db) using different solar drying methods compared to ascorbic acid and butylated hydroxytoluene at concentration of 100 μg/ml.

Treatment	DPPH ethanol%	FRAP (mg equivalence of AA or BHT)		Total antioxidant (mg equivalence of AA or BHT)
		Ethanol	Aqueous	Ethanol	Aqueous
Fresh	104.45 ± 0.35^a	0.55 ± 0.01^a	0.23 ± 0.01^a	0.33 ± 0.01^a	0.22 ± 0.01^a
SSSD	95.30 ± 0.42^b	0.21 ± 0.01^c	0.12 ± 0.00^b	0.18 ± 0.00^c	0.08 ± 0.00^b
CSD	95.57 ± 0.35^b	0.35 ± 0.00^b		0.20 ± 0.01^b	0.07 ± 0.00^b
OSD	78.90 ± 0.60^c	0.22 ± 0.00^c	0.11 ± 0.00^b	0.17 ± 0.00^c	0.04 ± 0.00^c
Ascorbic acid	95.30 ± 0.42	0.92 ± 0.00	0.79 ± 0.02	0.49 ± 0.00	0.57 ± 0.00
BHT	85.51 ± 0.70	0.49 ± 0.00

Data is represented as mean ± standard deviation of three replicate readings. Means in a column with different superscripts are significantly different at . CSD: tent-like concrete solar-dried ginger rhizome. SSSD: stainless steel solar-dried ginger rhizome. OSD: open-sun-dried ginger rhizome. FRAP: Ferric Reducing Antioxidant Power Assay. DPPH: 2,2-diphenyl-1-picrylhydrazyl. AA: ascorbic acid. BHT: butylated hydroxytoluene.