Bioactive Flavonoids, Antioxidant Behaviour, and Cytoprotective Effects of Dried Grapefruit Peels (Citrus paradisi Macf.)

Table 1

Total Polyphenol Index (TPI), DPPH, FRAP, and ABTS assays mean values and standard deviation (SD) of untreated, oven-dried, and freeze-dried grapefruit peel extracts.

	TPI	DPPH	FRAP	ABTS
	Mean ± SD	Mean ± SD	Mean ± SD	Mean ± SD
Fresh white grapefruit	49.14^a  ±  7.91	32.46^a  ±  0.80	60.30^a  ±  3.25	122.34^a  ±  6.22
Fresh pink grapefruit	27.95^b  ±  0.83	25.18^a  ±  8.52	44.82^b  ±  5.35	99.46^a  ±  12.09
White grapefruit dried at 45°C	52.95^a  ±  4.83	48.05^b  ±  3.75	71.57^a  ±  0.60	194.81^b  ±  3.80
Pink grapefruit dried at 45°C	42.29^a  ±  3.30	35.26^a  ±  3.62	65.86^a  ±  5.28	175.87^b  ±  5.64
White grapefruit dried at 60°C	63.35^c  ±  0.84	86.76^c  ±  8.40	105.86^c  ±  22.39	339.66^c  ±  33.61
Pink grapefruit dried at 60°C	49.36^ac  ±  3.57	50.07^b  ±  2.26	79.43^ac  ±  5.16	210.78^b  ±  2.19
Freeze-dried white grapefruit	84.60^d  ±  10.80	122.83^d  ±  15.95	181.80^d  ±  25.97	537.48^d  ±  36.10
Freeze-dried pink grapefruit	66.70  ±  1.54	110.98^d  ±  13.76	207.74^d  ±  14.65	455.38  ±  1.95

TPI are expressed as mg gallic acid equivalents per gram of dry weight.
DPPH, FRAP, and ABTS assays are expressed as mg trolox per gram of dry weight.
Different letters in the same column denote a significant difference according to the Student-Newman-Keuls test, at .