Determination of phenolic profile and antioxidant activity of pistachio hull using high-performance liquid chromatography–diode array detector–electro-spray ionization–mass spectrometry as affected by ultrasound and microwave

ABSTRACT

The phytochemicals content and radical scavenging activity of pistachio (Pistacia vera L.) hull extract obtained by different solvents (water, ethanol, and butanol) were measured and compared. Water was selected as superior solvent. Ultrasound-assisted aqueous extraction of the hull by power ultrasound (35 kHz) was more efficient in ascending the phytochemicals content than the sonochemical ultrasonication (130 kHz). High-performance liquid chromatography-mass spectrometry showed increased amounts of vanillic acid, p-coumaric acid, naringenin, and catechin in ultrasound-assisted extracts. Post-extraction sonication declined significantly the phenolics amount and antioxidant property of the aqueous extract. Microwave-assisted extraction increased the phenolics and flavonoids content at extract in a power-dependent trend.

KEYWORDS:

• Pistachio (Pistacia vera L.)
• Phenolic compounds
• Ultrasound-assisted extraction
• Microwave-assisted extraction
• HPLC-MS analysis