Antioxidant Activity of Pomegranate Juice and Its Relationship with Phenolic Composition and Processing

TLDR

The study assessed antioxidant activity of pomegranate juices using ABTS, DPPH, DMPD, and FRAP assays and compared the results to red wine and green tea. Commercial pomegranate juices exhibited antioxidant activity 18–20 TEAC, roughly three times higher than red wine and green tea (6–8 TEAC), and higher than experimental aril‑only juices (12–14 TEAC); HPLC analysis showed commercial juices contained abundant punicalagin (1500–1900 mg L⁻¹) and other phenolics, indicating that industrial processing extracts rind tannins that enhance antioxidant capacity. Keywords include pomegranate, punicalagin, tannins, anthocyanins, ellagic acid, and antioxidant assays ABTS, DPPH, DMPD, FRAP.

Abstract

The antioxidant activity of pomegranate juices was evaluated by four different methods (ABTS, DPPH, DMPD, and FRAP) and compared to those of red wine and a green tea infusion. Commercial pomegranate juices showed an antioxidant activity (18−20 TEAC) three times higher than those of red wine and green tea (6−8 TEAC). The activity was higher in commercial juices extracted from whole pomegranates than in experimental juices obtained from the arils only (12−14 TEAC). HPLC-DAD and HPLC-MS analyses of the juices revealed that commercial juices contained the pomegranate tannin punicalagin (1500−1900 mg/L) while only traces of this compound were detected in the experimental juice obtained from arils in the laboratory. This shows that pomegranate industrial processing extracts some of the hydrolyzable tannins present in the fruit rind. This could account for the higher antioxidant activity of commercial juices compared to the experimental ones. In addition, anthocyanins, ellagic acid derivatives, and hydrolyzable tannins were detected and quantified in the pomegranate juices. Keywords: Pomegranate; Punica granatum; Punicaceae; juice; phenolics; anthocyanins; ellagic acid; punicalagin; tannins; antioxidant activity; ABTS; DPPH; DMPD; FRAP