Table 1. Extraction conditions of all extraction methods, total phenolic content (TPC), total flavonoid content (TFC) and antioxidant activity of the extracts of artichoke leaves.
| Sample code |
Parameter | t/min | TPC as w(GAE)/(mg/g) | TFC as w(CE)/(mg/g) | TEAC as b(TE)/(mM/g) | DPPH inhibiton/% |
|---|---|---|---|---|---|---|
| MAE1 | P=800 W | 0.5 | (3.72±0.03)a | (8.3±0.3)a | (57.9±2.4)a | (85.2±1.7)a |
| MAE2 | P=440 W | 0.75 | (3.4±0.4)a | (6.50±0.01)b | (50.0±0.1)bc | (70.7±2.3)e |
| UAEp1 | Continuous process | 30 | (2.72±0.00)b | (6.6±0.5)b | (51.4±4.2)bc | (84.1±2.5)ab |
| UAEp2 | Continuous process | 15 | (2.4±0.5)bc | (6.1±0.1)bc | (42.2±6.5)d | (79.9±3.2)cd |
| UAEp3 | Pulsed process (50 % duty cycle) | 30 | (2.7±0.6)b | (6.5±0.7)b | (52.0±0.8)b | (81.2±0.5)bc |
| UAEp4 | Pulsed process (50 % duty cycle) | 15 | (2.48±0.04)bc | (5.6±0.3)cd | (46.2±1.8)cd | (77.4±1.7)d |
| UAEwb1 | P=240 W | 30 | (2.5±0.6)bc | (5.3±0.2)d | (42.8±0.8)d | (69.4±1.3)ef |
| UAEwb2 | P=240 W | 15 | (1.9±0.1)c | (3.2±0.4)g | (32.4±1.6)e | (66.4±1.4)fg |
| UAEwb3 | P=120 W | 30 | (2.3±0.3)bc | (4.3±0.5)e | (32.1±2.2)e | (69.9±1.5)ef |
| UAEwb4 | P=120 W | 15 | (1.9±0.5)c | (4.0±0.8)efg | (34.0±5.8)e | (63.6±2.6)g |
| M1 | - | 1440 | (2.0±0.1)c | (4.0±0.1)ef | (43.3±1.9)d | (69.4±1.7)ef |
| M2 | - | 720 | (1.89±0.02)c | (3.55±0.05)fg | (42.6±2.8)d | (60.0±1.7)h |
All results are expressed as the mean value±standard deviation, N=4. Mean values within each column followed by different letters in superscript are significantly different at p≤0.01. MAE=microwave-assisted extraction, UAEp=ultrasound-assisted extraction with probe, UAEwb=ultrasound-assisted extraction in a water bath, M=maceration, GAE=gallic acid equivalents, CE=catechin equivalents, TE=Trolox equivalents