Table 2.

Effect of processing on the antioxidant content of some foods

S/N	Food	Type of processing	Effect of processing on antioxidant content (%) compared to non-processed food
1.	Apple	Peeling	(−) 33–66 %
2.	Carrots	Steaming	(+) 291 %
3.	Carrots	Boiling	(+) 121–159 %
4.	Cucumbers	Peeling	(−) 50 %
5.	Asparagus	Steaming	(+) 205 %
6.	Broccoli	Steaming	(+) 122–654 %
7.	Green cabbage	Steaming	(+) 448 %
8.	Red cabbage	Steaming	(+) 270 %
9.	Green pepper	Steaming	(+) 467 %
10.	Red pepper	Steaming	(+) 180 %
11.	Potatoes	Steaming	(+) 105–242 %
12.	Tomatoes	Steaming	(+) 112–164 %
13.	Spinach	Boiling	(+) 114–184 %
14.	Sweet potatoes	Steaming	(+) 413

Source Hadvorsen et al. (2006)