Extraction Optimization and Antioxidant Properties of African Eggplant (Solanum macrocarpon) Leaf Polyphenols

Table 3

Test of significance for regression coefficient of Box–Behnken design.

Source	Sum of squares	Df	Mean square	value	value
Yield
	44.96	1	44.96	54.00	0.0007
	10.57	1	10.57	12.70	0.0162
	25.97	1	25.97	31.20	0.0025
	17.83	1	17.83	21.42	0.0057
	0.80	1	0.80	0.97	0.3707
	19.40	1	19.40	23.30	0.0048
	3.97	1	3.97	4.77	0.0806
	0.19	1	0.19	0.23	0.6532
	0.40	1	0.49	0.59	0.4782
Total polyphenol content
	20328.34	1	20328.34	37.53	0.0017
	361.54	1	361.54	0.67	0.4511
	5.14	1	5.14		0.9262
	1076.82	1	1076.82	1.99	0.2176
	3.69	1	3.69		0.9375
	65190.86	1	65190.86	120.36	0.0001
	87603.73	1	87603.73	161.74	0.0001
	6457.52	1	12858.37	11.92	0.0046
	12858.37	1	12858.37	23.74	0.0046
Total antioxidant activity
	13.55	1	13.55	17.77	0.0084
	1.82	1	1.82	2.39	0.1826
	12.48	1	12.48	16.36	0.0099
	0.79	1	0.79	1.04	0.3548
	2.58	1	2.58	3.38	0.1254
	3.92	1	3.92	5.14	0.0727
	98.45	1	98.45	129.63	0.0001
	50.04	1	50.04	65.63	0.0005
	32.21	1	32.21	42.25	0.0013

Note. Values are significantly different at .