Table 2. Central composite design and results of the dependent variable for solubility of hempseed protein isolate

Run	Independent variable			Solubility (%)
	Hydrolysis time (min)	Enzyme concentration (mg/mL)	pH	Predicted	Experimental
1	150 (−1)	1 (−1)	7.5 (−1)	50.5314	49.85471
2	150 (−1)	1 (−1)	8.5 (1)	50.52178	50.78244
3	150 (−1)	2 (1)	7.5 (−1)	47.41141	47.51218
4	150 (−1)	2 (1)	8.5 (1)	49.60819	49.49521
5	210 (1)	1 (−1)	7.5 (−1)	50.54949	49.30966
6	210 (1)	1 (−1)	8.5 (1)	52.38373	52.3132
7	210 (1)	2 (1)	7.5 (−1)	48.82108	48.59067
8	210 (1)	2 (1)	8.5 (1)	52.86172	52.18564
9	180 (0)	1.5 (0)	8 (0)	52.19616	52.35959
10	180 (0)	1.5 (0)	8 (0)	52.19616	52.92782
11	180 (0)	1.5 (0)	8 (0)	52.19616	52.6495
12	120 (−2)	1.5 (0)	8 (0)	47.84955	47.73252
13	240 (2)	1.5 (0)	8 (0)	51.12117	51.89572
14	180 (0)	0.5 (−2)	8 (0)	51.4999	51.33908
15	180 (0)	2.5 (2)	8 (0)	48.85789	48.98496
16	180 (0)	0.5 (−2)	7 (−2)	48.9786	49.66916
17	180 (0)	1.5 (0)	9 (2)	51.49949	51.46664
Critical value		Solubility (%)
Time (min)	Enzyme concentration (mg/mL)	pH	Predicted	Actual
				EH1)	CON2)
215	1.75	8.7	53.20	53.23±0.05	3.73±0.17

EH, hempseed protein enzymatically hydrolyzed with optimal condition.
CON, untreated hempseed protein control.