Optimization of process variables of probe ultrasonic‐assisted extraction of phenolic compounds from the peel of Punica granatum Var. Bhagwa and it's chemical and bioactivity characterization

This study was aimed to obtain maximum yield of phenolic compounds from Punica granatum peel (Bhagwa) by using ultrasonic‐assisted extraction process. Response surface methodology (RSM) was used to investigate the effect of process variables (amplitude and time) on extraction yield (EY), total phenolic content (TPC), total ellagitannin (TE) and antioxidant activity (AA) at a constant temperature of extraction (50 ± 1°C). Extraction of time (15.12 min) and amplitude (30%) were found to be optimum process conditions and gave maximum yield 42.45%, TPC 354.67 mg GAE/g, TE 348.0 mg TAE/g, and AA 94.78% DPPH scavenging. HPLC analysis of DPPE showed that it contained punicalagin (163.52 mg/g of DPPE) as major ellagitannin compound. SEM showed ultrasonication effectively disrupts the cell wall and improved the extraction efficiency. TGA profile revealed that extract was stable up to 220°C. Peel extract showed high antibacterial activity against both gram‐positive and gram‐negative bacteria. Practical applications Findings of the present investigation would be applied for the utilization of pomegranate (Punica granatum) processing waste or peels, converting it into health‐promoting phenolic bioactive compounds or nutraceuticals and its future application in the development of natural preservatives as well as functional food products.