Table 1.

Single and combined effect of freezing and frozen storage on the antioxidant activity of fruits.

												Effects
Vegetable	Freezing System	Freezing T (°C)	Storage T (°C)	Storage Time	Pre-Treatment	Post-Process	AOA Test					Freezing	Storage	Freezing and Frozen Storage	Data Expression	References
beet green	flo-freezer	nr	ns		blanching					ORAC		decrease			fw	[105]
broccoli	nr	−40	−20	6, 12, 18 months	blanching			DPPH					no effect		dw	[103]
	blast chamber	−40	−20	4, 8, 12 months	blanching	cooking		DPPH						decrease	fw	[113]
	IQF	−26	ns		blanching				FRAP			no effect			dw	[108]
	industrial freezing	nr			blanching					ORAC		decrease			dw	[106]
	blast freezer	−30			blanching			DPPH				no effect			dw	[107]
	blast freezer	−30			untreated			DPPH				decrease			dw	[107]
	nr	−22			blanching		ABTS					no effect			fw	[110]
	flo-freezer	nr	ns		blanching					ORAC		no effect			fw	[105]
brussels sprouts		−35	−18	2, 4, 6, 8 months	blanching	boiling		DPPH						DRP	fw	[116]
	nr	−22			blanching		ABTS					decrease			fw	[110]
cabbage	nr	−40	−20	6, 12, 18 months	blanching			DPPH					no effect		dw	[103]
capsicum varieties	home	−20	−20	4 months	untreated		ABTS	DPPH	FRAP		β-CB			decrease	fw	[120]
carrots	flo-freezer	nr	ns		blanching					ORAC		decrease			fw	[105]
	nr	−40	−20	6, 12, 18 months	blanching			DPPH					no effect		dw	[103]
	blast freezer	−30			blanching			DPPH				no effect			dw	[107]
	blast freezer	−30			untreated			DPPH				no effect			dw	[107]
	home freezer	−18	−18	6 months	untreated		ABTS							decrease	fw	[16]
cauliflower	chamber freezer	−22	−22	24 h + 1, 2, 3 months	blanching		ABTS					no effect	no effect		dw	[109]
	nr	−40	−20	6, 12, 20 months	blanching			DPPH					no effect		dw	[103]
cauliflower	freezer	−24	−24	3, 6, 12 months	blanching				FRAP	ORAC				DRM	fw	[117]
	nr	−22			blanching		ABTS					no effect			fw	[110]
	blast freezer	−40	−20	4, 8, 12 months	cooking			DPPH						decrease	fw	[121]
celery	flo-freezer	nr	ns		blanching					ORAC		decrease			fw	[105]
green asparagus	chamber freezer	−20	−20	4, 8, 12 months	blanching	boiling		DPPH				decrease	decrease		dw	[112]
	chamber freezer	−30	−30	4, 8, 12 months	cooking	heating		DPPH				decrease	decrease		dw	[112]
green beans	home freezer	−23	−27		blanching			DPPH						no effect	fw	[48]
	home freezer	−23	−27		blanching			DPPH						no effect	fw	[48]
	industrial freezing	nr			blanching					ORAC		no effect			dw	[106]
	blast freezer	−30			blanching			DPPH				no effect			dw	[107]
	blast freezer	−30			untreated			DPPH				no effect			dw	[107]
	home freezer	−18	−18	6 months	untreated		ABTS							increase	fw	[16]
kale	blast freezer	−20	−20	12 months	blanching		ABTS					no effect	no effect		fw	[98]
	blast freezer	−30	−30	12 months	blanching							no effect	no effect		fw	[98]
	nr	−22			blanching		ABTS					no effect			fw	[110]
onion	flo-freezer	nr	ns		blanching					ORAC		increase			fw	[105]
peas	fluidization tunnel	−18	−18	12 months	blanching		ABTS	DPPH			Fe2+			DRM	dw	[118]
	nr	−40	−20	6, 12, 18 moths	blanching			DPPH					decrease		dw	[103]
	nr	−30	−20	21 days	blanching				FRAP			decrease	no effect		fw	[102]
	home freezer	−18	−18	6 months	untreated		ABTS							increase	fw	[16]
potato	nr	−40	−20	6, 12, 18 months	blanching			DPPH					no effect		dw	[103]
spinach	flow-freezer	nr	ns		blanching					ORAC		decrease			fw	[105]
	nr	−40	−20	6, 12, 18 months	blanching			DPPH					no effect		dw	[103]
	industrial freezing	nr			blanching					ORAC		decrease			dw	[106]
	nr	−30	−20	21 days	blanching				FRAP			decrease	no effect		fw	[102]
string beans	fluidization tunnel	−18	−18	12 months	blanching		ABTS	DPPH			Fe2+			DRM	dw	[118]
swede	nr	−40	−20	6, 12, 18 months	blanching			DPPH					slight decrease		dw	[103]
tomato	home freezer	−18	−18	6 months	untreated		ABTS							no effect	fw	[16]
turnip greens	chamber freezer	−30	−30	up to 28 days	untreated			DPPH						decrease	dw	[119]
	chamber freezer	−30	−30	up to 28 days	blanching			DPPH						decrease	dw	[119]
yellow pepper	home freezer	−18	−18	6 months	untreated		ABTS							decrease	fw	[16]
zucchini	home freezer	−18	−18	6 months	untreated		ABTS							increase	fw	[16]

ORAC: Oxygen Radical Absorbance Capacity; FRAP: Ferric Reducing Antioxidant Power; ABTS: 2,2′-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) radical cation assay; DPPH: 2,2-diphenyl-1-picrylhydrazyl free radical assay; β-CB: β-carotene bleaching; Fe²⁺: Fe²⁺ chelating ability; IQF: Individual Quick Freezing; dw: dry weight; fw: fresh weight; nr: not reported; ns: no storage; DRM: discordant results between the method applied for the antioxidant activity (AOA) determination; DRP: different results depending on the blanching pre-treatment applied.