Comparison of microwave, ultrasound and ultrasound-microwave assisted solvent extraction methods on phenolic profile and antioxidant activity of extracts from jackfruit (Artocarpus heterophyllus Lam.) pulp

Abstract

This study aimed to investigate the impact of different solvents (water, 60% methanol, 60% ethanol and 60% acetone) and methods (conventional solvent extraction, ultrasound-assisted extraction, microwave-assisted extraction and ultrasound-microwave assisted extraction) on the phenolic profile and antioxidant activity of jackfruit (Artocarpus heterophyllus Lam.) pulp. The Folin-Ciocalteu assay was used to determine the total phenolic content (TPC), and antioxidant activity was measured by DPPH and ABTS assays. The phenolic profiles in different extracts were identified using the UPLC-ESI-Q-TOF-MS/MS technique. The results showed that significant differences (p < 0.05) in TPC were found among different extraction methods, the microwave-assisted extraction with 60% ethanol had the highest TPC (2.40 mg GAE/g) compared with the extracts obtained from other methods. Meanwhile, the highest DPPH radical and ABTS radical cation was found in the 60% ethanol-MAE extracts. Correlation analysis further showed a significant positive correlation between TPC and antioxidant activity (R2 > 0.8, p < 0.001). Seventy-eight phenolic compounds were identified by UPLC-ESI-Q-TOF-MS/MS analysis. The most abundant phenolic compounds in jackfruit pulp were identified in negative mode, with 60% ethanol-MAE being the most effective. The quantity of phenolic compounds extracted varied with different extraction methods indicated that the extraction methods had effects on the phytochemical characteristics.