Table 2. Total polyphenol, flavonoid, and proanthocyanidin contents of 70% ethanol extracts of grape fruit stem with different drying methods

(mg/g, dry basis)

Mesurement GFSF¹⁾ GFSI²⁾ GFSH³⁾ GFSS⁴⁾

Polyphenols (mg GAE⁵⁾/g) 270.09±5.71⁸⁾^a⁹⁾ 268.44±3.75^a 252.49±2.45^b 253.03±3.13^b

Flavonoids (mg RHE⁶⁾/g) 58.35±1.20^c 64.57±0.76^a 61.65±2.24^b 59.46±1.41^b^c

Proanthocyanidins (mg CE⁷⁾/g) 193.47±2.62^a 181.30±2.54^b 159.60±1.61^c 157.13±1.71^c

¹^-⁴⁾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.
⁵^-⁷⁾GAE, gallic acid equivalents; RHE, rutin hydrate equivalents; CE, catechin hydrate equivalents.
⁸⁾Values are means±SD of triplicate determinations.
⁹⁾Different superscripts within a row (a-d) indicate significant differences (p<0.05).

Mesurement	GFSF¹⁾	GFSI²⁾	GFSH³⁾	GFSS⁴⁾
Polyphenols (mg GAE⁵⁾/g)	270.09±5.71⁸⁾^a⁹⁾	268.44±3.75^a	252.49±2.45^b	253.03±3.13^b
Flavonoids (mg RHE⁶⁾/g)	58.35±1.20^c	64.57±0.76^a	61.65±2.24^b	59.46±1.41^b^c
Proanthocyanidins (mg CE⁷⁾/g)	193.47±2.62^a	181.30±2.54^b	159.60±1.61^c	157.13±1.71^c