Table 1.

Experimental design and observed responses for trans-resveratrol production in grape skin obtained by US abiotic treatment

Run	Factor 1 X1: Physical characteristics of the grape	Factor 2 X2: Incubation time (h)	Factor 3 X3: US Application method	Factor 4 X4:US Frequency (kHz)	Factor 5 X5:US Treatment time (min)	Ultrasonic intensity (UI) (W cm−2)	Y1 trans-resveratrol (mg/g)
1	Fresh	48	Steady	30	60	7.24	0.63 ± 0.02
2	Fresh	48	Periodic (P05)	30	60	3.65	1.91 ± 0.10
3	Fresh	72	Periodic (P01)	20	60	1.15	0.21 ± 0.01
4	Fresh	72	Periodic (P05)	30	10	0.75	0.21 ± 0.02
5	Frozen	24	Periodic (P05)	30	10	0.75	0.83 ± 0.05
6	Frozen	48	Steady	20	10	0.95	0.51 ± 0.03
7	Frozen	48	Periodic (P05)	20	10	0.54	0.60 ± 0.03
8	Frozen	72	Periodic (P01)	20	10	0.34	0.26 ± 0.02
9	Fresh	24	Periodic (P05)	30	10	0.75	2.73 ± 0.11
10	Fresh	48	Periodic (P01)	20	10	0.34	0.28 ± 0.00
11	Frozen	72	Periodic (P05)	30	60	3.65	0.56 ± 0.02
12	Frozen	48	Steady	30	60	7.24	0.63 ± 0.02
13	Frozen	48	Steady	30	10	1.45	0.65 ± 0.02
14	Frozen	24	Periodic (P01)	20	10	0.34	0.17 ± 0.00
15	Frozen	48	Periodic (P01)	20	60	1.15	1.33 ± 0.05
16	Frozen	24	Steady	20	10	0.95	0.19 ± 0.01
17	Fresh	48	Steady	30	10	1.45	1.30 ± 0.04
18	Frozen	48	Periodic (P05)	30	60	3.65	1.09 ± 0.01
19	Fresh	72	Periodic (P05)	30	60	3.65	0.29 ± 0.00
20	Fresh	48	Steady	20	10	0.95	0.51 ± 0.02
21	Fresh	72	Steady	20	10	0.95	0.24 ± 0.01
22	Frozen	72	Steady	20	60	4.48	0.37 ± 0.02
23	Fresh	24	Periodic (P01)	20	10	0.34	1.74 ± 0.04
24	Frozen	72	Periodic (P05)	30	10	0.75	0.85 ± 0.01
25	FRESH	72	Periodic (P05)	20	10	0.54	0.24 ± 0.00
26	Fresh	72	Periodic (P05)	30	60	3.65	0.29 ± 0.00
27	Fresh	24	Periodic (P01)	20	60	1.15	3.62 ± 0.10
28	Fresh	24	Periodic (P05)	30	60	3.65	2.92 ± 0.08
29	Frozen	24	Steady	30	60	7.24	0.35 ± 0.00
30	Fresh	24	Steady	20	60	4.48	0.33 ± 0.00
31	Frozen	72	Periodic (P05)	20	60	1.89	0.56 ± 0.01
32	Frozen	24	Periodic (P05)	30	60	3.65	0.22 ± 0.00

Analytical results are the average of triplicates (mean ± SD)