Assessment of Minerals, Bioactive Compounds, and Antioxidant Activity of Ten Moroccan Pomegranate Cultivars

The attractiveness of pomegranate (Punica granatum L.) is increasing worldwide among producers and consumers. Depending on its characteristics, the pomegranate may be intended for fresh consumption, for industrial processing, or for medical purposes. This study aims to assess the variability in terms of mineral content and biochemical properties of ten selected pomegranate cultivars grown in the center of Morocco to better know their fruit potential. Mineral composition, organic acids, total polyphenols, anthocyanins content, individual phenolic compounds, and antioxidant activity were determined in pomegranate juices. Results showed significant differences between cultivars. The sour cultivar “Lhamdha” is rich in organic acids, gallagyl esters, and ellagitannins and showed high antioxidant activity. It could therefore be used as a source for nutraceutical substances. The cultivar “Sefri” of Lalla Takerkoust showed important content of mineral elements, especially iodine (I), calcium (Ca), magnesium (Mg), iron (Fe), and silver (Ag). The cultivars “Sefri” of Ouled Abdellah, “Sefri” of Beni Meskine, “Lahmer,” and “Marrakchia” are suitable for production of fresh pomegranate juice with high potential of health benefits. In fact, they are rich in anthocyanins, polyphenols, and oxalic and ascorbic acids and they presented high antioxidant activity. While the cultivars “Sefri” of Sour Laaz, “Sefri” of Tmassine, “Sefri” of Sidi Abdellah, and “Bzeq Tir” could be intended for fresh fruit consumption. Cluster analysis has revealed the divergence of cultivars with the same appellation “Sefri” confirming the problem of homonymy or synonymy in the pomegranate cultivars appellation. This study clearly demonstrates the nutritional and functional potential of the studied cultivars and the importance of their valorisation, especially for food and pharmaceutical industries

Assessment of the antioxidant and antibacterial activities of different olive processing wastewaters

<div><p>Olive processing wastewaters (OPW), namely olive mill wastewater (OMW) and table-olive wastewaters (TOW) were evaluated for their antibacterial activity against five Gram-positive and two Gram-negative bacteria using the standard disc diffusion and thin layer chromatography (TLC)-bioautography assays. Disc diffusion screening and bioautography of OMW were compared to the phenolic extracts of table-olive brines. Positive activity against <i>S</i>. <i>aureus</i> was demonstrated. The optimization of chromatographic separation revealed that hexane/acetone in the ratio of 4:6 was the most effective for phenolic compounds separation. A HPLC-MS analysis was performed showing that only two compounds, hydroxytyrosol and tyrosol, were the predominant phenolic compounds in all OPW. The phenolic extract of OMW generated by a semi-modern process showed the highest free radical-scavenging activity (DPPH assay) compared to the other phenolic extracts. It is apparent from the present study that OPW are a rich source of antioxidants suitable for use in food, cosmetic or pharmaceutical applications.</p></div

Effect of concentration of OMW and TOW phenolic extracts on their antibacterial activity against <i>S</i>. <i>aureus</i> using the disc diffusion assay.

<p>Effect of concentration of OMW and TOW phenolic extracts on their antibacterial activity against <i>S</i>. <i>aureus</i> using the disc diffusion assay.</p

Physicochemical characterization of olive mill wastewater and table-olive brine samples.

<p>Physicochemical characterization of olive mill wastewater and table-olive brine samples.</p

HPLC chromatograms of OMW phenolic extracts.

<p>1. Hydroxytyrosol, 2. 3,4-dihydroxyphenylacetic acid, 3. Tyrosol. 4. Protocatechuic acid derivative, 5. Caffeic acid. 6. <i>p</i>-coumaric acid. 7. Ferulic acid derivative, 8. Ferulic acid, 9. Luteolin derivative, 10. Oleuropein. Peaks 1, 3, 6, 8 and 10 were identified by use of standards. The remaining peaks were tentatively identified by comparison with literature data. (OMW1: olive mill wastewater from semi-modern process, OMW2: olive mill wastewater from modern process, GTOW: green table-olive brine, PTOW: purple table-olive brine and BTOW: black table-olive brine).</p

Total phenolic content, phenolic constituents and antioxidant activity (IC₅₀) of different olive processing wastewaters samples.

<p>The values in the brackets are the proportions to the total phenolic content, TPC.</p