Impact of processing and storage on the phenolic profiles and contents of pomegranate (Punica granatum L.) juices
ABSTRACT Juices were obtained on pilot-plant scale from untreated, steamed and peeled pomegranate fruits (Punica granatum L.), respectively, by applying increasing pressures and various juice treatments, i.e., enzymatic treatment, filtration,
clarification and pasteurization, to determine the influence of process technology on the phenolic profiles and contents of
the juices. Polyphenols were characterized and quantified by HPLC-DAD-ESI/MSn, and total phenolics and antioxidant capacity of the juices were determined by Folin–Ciocalteu, FRAP and TEAC assays, respectively.
The total amounts of anthocyanins and colorless phenolics in the juices significantly differed depending on the applied technology.
Highest phenolic recoveries were obtained from steamed fruits without further treatment. In contrast, lowest phenolic contents
were determined in the juices produced from peeled fruits, i.e., the isolated seeds with adherent arils. With increasing pressures,
polyphenol recoveries were enhanced, whereas juice treatments such as microfiltration and fining lowered phenolic contents
of the juices. Furthermore, the amounts of individual phenolics were determined by HPLC-DAD with ellagitannins dominating
the phenolic profiles. Juices solely produced from the edible parts of pomegranate exhibited lower amounts of ellagitannins
compared with the juices from entire fruits. In contrast, the former juices were characterized by the highest amounts of gallotannins,
hydroxybenzoic acids, hydroxycinnamic acids and dihydroflavonols. These results were consistent with the astringency of the
juices. Additionally, storage experiments were performed at 4°C and 20°C in the dark and 20°C under light exposure, revealing
significant pigment degradation and concomitant color loss, especially at elevated temperatures and upon illumination, whereas
the contents of non-anthocyanin phenolics and antioxidant capacity remained virtually unchanged throughout storage.
KeywordsPomegranate–Phenolic compounds–Juice processing–Storage–Antioxidant capacity
Article: Rapid and Comprehensive Evaluation of (Poly)phenolic Compounds in Pomegranate (Punica granatum L.) Juice by UHPLC-MS n[show abstract] [hide abstract]
ABSTRACT: The comprehensive identification of phenolic compounds in food and beverages is a crucial starting point for assessing their biological, nutritional, and technological properties. Pomegranate (Punica granatum L.) has been described as a rich source of (poly)phenolic components, with a broad array of different structures (phenolic acids, flavonoids, and hydrolyzable tannins) and a quick, high throughput, and accurate screening of its complete profile is still lacking. In the present work, a method for UHPLC separation and linear ion trap mass spectrometric (MS n) characterization of pomegranate juice phenolic fraction was optimized by comparing several different analytical conditions. The best solutions for phenolic acids, anthocyanins, flavonoids, and ellagitannins have been delineated and more than 70 compounds have been identified and fully characterized in less than one hour total analysis time. Twenty-one compounds were tentatively detected for the first time in pomegranate juice. The proposed fingerprinting approach could be easily translated to other plant derived food extracts and beverages containing a wide array of phytochemical compounds.Molecules 12/2012; 17(12):14821-14840. · 2.39 Impact Factor