Recovering phenolic compounds from Eugenia calycina Cambess employing high-intensity ultrasound treatments: A comparison among its leaves, fruit pulp, and seed as promising sources of bioactive compounds

Abstract This study aimed to evaluate the effects of the high-intensity ultrasound (HIUS) on the recovery of phenolic compounds from the leaves, fruit pulp, and seed of Eugenia calycina Cambess. The impact of using different modes of application of the same ultrasound-specific energy (kJ/g) was examined. Ultrasound energy performance was assessed employing two different HIUS treatments for each part plant. The same specific energy levels of 2 and 5 kJ/g were applied, varying nominal power and processing time. The HIUS treatments of low-power and long-time (LPLT) and high-power and short-time (HPST) were performed at 100 W, and 475 W. LPLT treatment was non-thermal processing, while HPST was a thermal treatment. The HPST treatment showed more efficiency in the recovery of the phenolic compounds to specific energies. The leaves were the plant part that exhibited the highest content of phenolic compounds and antioxidant activity. The LC-MS analysis also showed ellagic acid and myricitrin as the main phenolic compounds in all botanical parts evaluated. The SEM showed a physical change in plant structure because of HIUS. However, the FTIR spectra indicated that the chemical functional groups were not affected by the acoustic energy. Despite the HPST treatment increased the medium temperature, the stability of antioxidant compounds was preserved. The interaction of the high nominal power, short processing time, and moderate temperature employed in the HPST extraction procedure positively affected the extraction yield of phenolic compounds from the Eugenia calycina.