Abstract
Syzygium cumini fruit is a rich source of excellent bioactive compounds, including polyphenols and flavonoids with high antioxidant potential and pharmacological properties. Yet, this plant’s improvement of the extraction yield of total polyphenol content (TPC) and antioxidant potential has never been inspected in depth. The objective of this study was to use a 23 factorial design with three repetitions of the central point to investigate the influence of combined parameters such as ultrasonication, solvent concentration, time, and temperature and to employ RSM to optimize the extraction of phenolic compounds from jambolão at three ripeness stages (unripe, mid-ripe and ripe) and maximize their antioxidant activity. The best conditions of the variables for increasing the yield, total phenolic and antioxidant capacity were obtained with 30 % ethanol for 68.4 min, at 39.2 °C for unripe jambolão, with 30 % ethanol for 30 min, at 47.2 °C for mid-ripe and with 90 % ethanol for 30 min, at 60 °C for ripe fruit. The yield, TPC, DPPH, ABTS and FRAP decreased during fruit ripeness. For such optimized conditions of ultrasound-assisted extraction, the highest yield and TPC were experimentally determined for the unripe stage at 9.01 % and 549.16 mg GAE/100g, respectively, with an antioxidant capacity of 45.19 mMol TE/100 g DPPH, 68.20 mMol TE/100 g ABTS and 72.30 mMol TE/100 g FRAP and agreed with the obtained model values. This study showed that it is possible to obtain bioactive-rich extracts from jambolão using experimental design to improve the extraction process.