Table 1.

The main factor extraction experimental design.

I. Single factor experimental design
Level Factors	S1 Reagent	S2 water-goji ratio (v/w)	S3 pH	S4 time (min)	S5 temperature (°C)
1	Hydrochloric acid	10:1	1.5	50	40
2	Nitric acid	15:1	2.0	60	50
3	Sulphuric acid	20:1	2.5	70	60
4	Citric acid	25:1	3.0	80	70
5	–	30:1	3.5	90	80
6	–	35:1	4.0	100	90
7	–	40:1	4.5	110	100
II. Experimental Design of BBD Response Surface
Level Factors	reagent	water-goji ratio (v/w)	A pH	B time (min)	C temperature (°C)
−1	–	–	1.5	70	70
0	–	–	2.0	80	80
1	–	–	2.5	90	90