ENHANCED RECOVERY OF BIOACTIVE COMPOUNDS FROM COCOA BEAN HUSK (Theobroma cacao) VIA PULSED ELECTRIC FIELD PRETREATMENT

Resumo: Pulsed electric field (PEF) enhances the extraction of bioactive compounds by promoting electroporation, which increases cell membrane permeability and facilitates intracellular release. However, extraction efficiency depends on plant matrix characteristics and processing conditions. This study assessed the impact of PEF on extracting bioactive and antioxidant compounds from cocoa bean shell (Theobroma cacao var. Forastero). Samples were subjected to three PEF intensities: CO6 (6 kV/cm), CO7 (7 kV/cm), and CO8 (8 kV/cm), with a pulse width of 25 µs, a frequency of 10 Hz, and 6000 pulses. Extraction was subsequently carried out using 80% ethanol (v/v) under stirring at 40 °C for 1 hour. The treatments significantly affected the color parameters (p≤0.05). Luminosity (L*) increased in CO6 (25.07±1.13, +26.3%) and CO7 (27.20±0.14, +37.0%), indicating a visual lightening effect, while CO8 showed a pronounced darkening (4.10±0.07, –79.3%) compared to the control (19.85±0.10). The a* coordinate was reduced in CO8 (25.10 ± 2.40), representing a 49.7% decrease compared to the control (49.90±0.00). For b*, CO7 showed the highest value (46.70±0.10), with a 35.7% increase, while CO8 had the lowest (8.90±2.70), a 74.1% reduction. The hue angle (h*) was highest in CO8 (74.50±1.40), increasing by 35.2%, and lowest in CO7 (48.80±0.70), with a decrease of 11.5%. Chroma (C*) increased in CO7 (72.20±0.85), with a 19.2% gain, and was lowest in CO8 (26.05±7.85), a 57.0% reduction compared to the control (60.60±0.00). The pH remained stable across treatments (5.71–5.72), indicating preservation of acidity. Regarding total phenolic compounds, CO8 had the highest content (166.30±0.00 mg GAE/g d.b., p ≤ 0.05), with an 11.2% increase, while CO6 and CO7 were lower. For total flavonoids, CO8 also stood out (67.20±0.73 mg RE/g d.b., p ≤ 0.05), with a 114% increase compared to the control (31.40±0.72 mg RE/g d.b., p ≤ 0.05). In terms of antioxidant activity, CO8 performed best in the ABTS assay (92.50±2.36 µM Trolox/g d.b., p ≤ 0.05), with a 796% increase, followed by CO6 (84.39±1.18 µM Trolox/g d.b.). In the DPPH assay, CO6 showed the best results (75.97±1.84 µM Trolox/g d.b., p ≤ 0.05), with a 253% increase, while CO8 (58.75±7.33, p ≤ 0.05) and CO7 (52.10±5.00, p ≤ 0.05) also outperformed the control (21.54±6.28, p ≤ 0.05). Therefore, the data indicate that PEF pre-treatment enhanced the extraction of bioactive compounds from the cocoa bean shell, with CO8 standing out for phenolics, flavonoids, and antioxidant activity (ABTS), and CO6 for antioxidant activity (DPPH).