Research Article

Optimization Conditions of Ultrasound-Assisted Extraction for Phenolic Compounds and Antioxidant Activity from Rubus alceifolius Poir Leaves

Table 1

Box–Behnken design of experimental conditions and observed responses for TPC and antioxidant capacity (ABTS radical scavenging activity) of R.A. Poir leaf extracted using ultrasonic-assisted extraction.

RunFactorsActual (mg GAE/g)Predicted (mg GAE/g)Prediction error (%)Actual (mg TE/g)Predicted (mg TE/g)Prediction error (%)
(W)a (°C)a (min)a

1300 (0)45 (0)30 (0)16.081.1821.162.39
2500 (+1)45 (0)55 (+1)7.15-0.148.970.22
3300 (0)45 (0)30 (0)16.570.0621.390.23
4300 (0)45 (0)30 (0)15.460.0620.592.87
5100 (-1)45 (0)55 (+1)12.540.3217.480.17
6300 (0)30 (-1)5 (-1)8.530.3513.190.30
7300 (0)60 (+1)55 (+1)6.54-0.926.982.58
8500 (+1)45 (0)5 (-1)12.451.7717.690.11
9500 (+1)60 (+1)30 (0)8.350.2410.180.69
10300 (0)45 (0)30 (0)16.55-0.0622.33-0.04
11100 (-1)30 (-1)30 (0)8.530.3513.080.23
12300 (0)30 (-1)55 (+1)11.983.6716.120.81
13300 (0)45 (0)30 (0)15.990.0621.460.05
14100 (-1)45 (0)5 (-1)6.46-0.626.51-0.77
15100 (-1)60 (+1)30 (0)8.310.1210.640.85
16500 (+1)30 (-1)30 (0)13.40-0.3718.370.16
17300 (0)60 (+1)5 (-1)8.64-0.1213.810.07

a, , and , respectively, denote the ultrasonic power (W), extraction temperature (°C), and extraction time (min). The values are .