TABLE 2.

Response surface design and free polyphenols content of the mung bean extracts.

Run	X1 (mmol/L)	X2 (W)	X3 (min)	FP content (mg GAE/g DW)
1	0 (10)	0 (360)	0 (30)	4.59 ± 0.04
2	0 (10)	0 (360)	0 (30)	4.44 ± 0.06
3	−1 (5)	0 (360)	1 (50)	4.25 ± 0.03
4	−1 (5)	0 (360)	−1 (10)	4.15 ± 0.02
5	0 (10)	1 (400)	−1 (10)	4.23 ± 0.04
6	1 (15)	0 (360)	−1 (10)	4.19 ± 0.01
7	0 (10)	0 (360)	0 (30)	4.43 ± 0.06
8	0 (10)	0 (360)	0 (30)	4.54 ± 0.03
9	1 (15)	−1 (320)	0 (30)	4.22 ± 0.05
10	0 (10)	−1 (320)	−1 (10)	3.97 ± 0.02
11	0 (10)	1 (400)	1 (50)	4.36 ± 0.01
12	0 (10)	0 (360)	0 (30)	4.39 ± 0.06
13	1 (15)	0 (360)	1 (50)	4.48 ± 0.03
14	−1 (5)	−1 (320)	0 (30)	3.84 ± 0.01
15	−1 (5)	1 (400)	0 (30)	4.31 ± 0.05
16	1 (15)	1 (400)	0 (30)	4.13 ± 0.04
17	0 (10)	−1 (320)	1 (50)	4.13 ± 0.05

Box-Behnken design was used to optimize the conditions for enrichment of mung bean with polyphenols (Table 2), and a regression model was established as follows: three independent variables, including GABA concentration (X₁), ultrasonic power (X₂), and ultrasonic time (X₃), on the free polyphenol contents, are represented.