Hédia Hannachi

Antioxidant Capacities of Phenolic Compounds and Tocopherols from Tunisian Pomegranate (Punica granatum) Fruits

This article aims to determine the phenolic, tocopherol contents, and antioxidant capacities from fruits (juices, peels, and seed oils) of 6 Tunisian pomegranate ecotypes. Total anthocyanins were determined by a differential pH method. Hydrolyzable tannins were determined with potassium iodate. The tocopherol (α-tocopherol, γ-tocopherol, and δ-tocopherol) contents were, respectively, 165.77, 107.38, and 27.29 mg/100 g from dry seed. Four phenolic compounds were identified and quantified in pomegranate peel and pulp using the high-performance liquid chromatography/ultraviolet method: 2 hydroxybenzoic acids (gallic and ellagic acids) and 2 hydroxycinnamic acids (caffeic and p-coumaric acids). Juice, peel, and seed oil antioxidants were confirmed by ferric reducing antioxidant power (FRAP) and oxygen radical absorbance capacity (ORAC) methods. The highest values were recorded in peels with 25.63 mmol trolox equivalent/100 g and 22.08 mmol TE/100 g for FRAP and ORAC assay, respectively. Results showed that the antioxidant potency of pomegranate extracts was correlated with their phenolic compound content. In particular, the highest correlation was reported in peels. High correlations were also found between peel hydroxybenzoic acids and FRAP ORAC antioxidant capacities. Identified tocopherols seem to contribute in major part to the antioxidant activity of seed oil. The results implied that bioactive compounds from the peel might be potential resources for the development of antioxidant function dietary food.

Oleaster (var. sylvestris) and subsp. cuspidata are suitable genetic resources for improvement of the olive (Olea europaea subsp. europaea var. europaea)

The olive belongs to Olea, a complex genus and to a species with six subspecies. Subsp. europaea includes both the cultivated olive and the oleaster, the wild ancestor of the olive. Little is known on the phenotype of fruits from subsp. cuspidata. We aimed to compare europaea and cuspidata trees for oil content and composition and to verify whether natural hybrids may exist between the two subspecies. Specimens were from Kenya and putative natural hybrids between cuspidata and europaea were from Stellenbosch (South Africa). Cultivar and oleaster trees were sampled in France (continental and Corsica), Italy (Continental and Sardinia) and Tunisia. We have examined the fruit (drupe) structure between subsp. cuspidata and europaea and extracted oil from the pulp, seed and total drupe. Comparison for oil content was made between the cultivated olive and the oleaster and some cuspidata trees from Kenya. A few of cuspidata individuals from Botanical gardens do not enable phenotyping for oil content and composition. Oil composition analyses were performed for the main fatty acids to compare the three taxa. We used microsatellite markers at 11 loci to compute genetic distances between cuspidata, oleaster and cultivar trees and to reveal eventual hybrids. The SSR polymorphisms were huge between the two subspecies and they revealed that putative hybrids were true hybrids sampled around olive orchards. The whole comparison of oil content shows that olive cultivars display higher oil content than the subsp. cuspidata and that the oleaster trees are intermediate, whereas for oil composition of the drupe, cuspidata from Kenya shows less oleic acid than europaea. However, the cuspidata trees show seed oil composition similarities with the other two taxa. The discussion deals with possible reasons to explain the differences and of the possible uses of these taxa for breeding both the olive and brown olive.

Screening of Natural Antioxidants from Selected Medicinal Plants

Medicinal plants contain high levels of natural antioxidants and exhibited strong antioxidant activity. In order to find new sources of natural antioxidants, a screening of natural antioxidants from some Tunisian medicinal plants commonly associated with treatment of some diseases were conducted. The total phenolic compounds, flavonoids, anthocyanins, and hydrolysables tannins were measured, and the antioxidant capacities were evaluated using DPPH and Trolox equivalent antioxidant capacity assays. Results prove that there are important quantities of these compounds in Tunisian medicinal plants. A positive linear correlation between Trolox equivalent antioxidant capacity and the phenolic compound contents suggested that these compounds were a major contributor of antioxidant activity of these plants. The results from this study will help us understand the antioxidant capacity profiles of these medicinal plants, and also investigate new sources of natural antioxidants.

The Use of ISSR and RAPD Markers for Genetic Diversity among South Tunisian Barley

Random amplified polymorphic DNA (RAPD) and intersimple sequence repeat (ISSR) were assayed to determine the genetic diversity of 80 barley specimens from South Tunisia. The ISSR primers showed variation in the percentage of polymorphism, band informativeness (Ib), and resolving power (Rp). The percentage of polymorphism is 66.67%, the average Ib ranged from 0.24 to 0.39, while Rp ranged from 0.74 to 1.16. In RAPD analysis, three primers yielded a total of 17 scorable bands, which are all polymorphic. The three polymorphic primers exhibited variation with regard to average band informativeness (AvIb) and resolving power (Rp). RAPD and ISSR marker systems were found to be useful for the genetic diversity among the barley specimens. The two dendrograms obtained through these markers show different clustering of 80 barely specimens, but we noted that some clusters were similar in some cases. A poor correlation (𝑟=0.12) was found between both sets of genetic similarity data, suggesting that both sets of markers revealed unrelated estimates of genetic relationships. Therefore, the ISSR and RAPD molecular markers show two genetic grouping of studied barely specimens.

Minor lipid components of some Acacia species: potential dietary health benefits of the unexploited seeds

BackgroundOilseed samples from four Acacia species ( A. cyclops, A. ligulata, A. salicina and A. cyanophylla) were analyzed in order to evaluate the potential nutritional value of their unexploited seeds.MethodsSamples were collected from different Tunisian geographic locations. Seed oils were extracted and carotenoids, tocopherols and sterols were analyzed using chromatographic methods.ResultsThe studied Acacia seeds seem to be quite rich in lipids (from 6% to 12%). All Acacia species contain mainly the xanthophylls zeaxanthin and lutein compounds: from ca. 38 mg.kg-1 of total lipids (A. cyclops) to ca. 113 mg.kg-1 of total lipids (A. cyanophylla). Total tocopherols varied from ca. 221 mg.kg-1 of total lipids (A. cyclops) to ca. 808 mg.kg-1 of total lipids (A. ligulata). Sterols are highly present and their contents ranged between ca. 7 g. kg-1 of total lipids (A. salicina) and 11 g. kg-1 of total lipids (A. cyclops).ConclusionThis study highlights that these unexploited seeds might have a potential nutritional value and encourages researchers to more explore and find developments for these plants for healthy purposes.

Effect of Different Drying Methods on the Physico-Chemical Properties of Tomato Variety 'Rio Grande'

The aim of this work is to study the physico-chemical properties of dried tomatoes, variety Rio grande using direct solar dryer (DSD), open-air sun drying (OASD) and microwave drying (MW) with three output powers density (1w/g; 2w/g; 3w/g) at different temperatures (57, 67°C). Radical scavenging activity of tomatoes extracts was investigated. Results indicated that drying tomatoes by microwave (3W/g; 67°C) is faster than open-air sun drying (OASD) and direct solar dryer (DSD). The studied parameters (moisture, pH, °Brix, total phenolics, total flavonoids, and carotenoids content) were significantly affected by different drying processes, with minimal effects on pH. The highest activity against the DPPH radical oxidation is investigated in methanolic extracts of tomatoes dried by direct solar dryer (DSD). Nevertheless, the highest ABTS value was observed in methanolic extracts of tomatoes dried by microwave (MW) with 3w/g at 57°C.

Flowering in the wild olive ( Olea europaea L.) tree (oleaster): Phenology, flower abnormalities and fruit set traits for breeding the olive

Although, the olive trees produce hermaphrodite flowers, abnormal flowers (flowers with absence or reduced stamens and flowers with absence of pistil) are frequently observed and may reduce fruit set. This study investigates the phenology evolution and the male and female abortion of the oleaster tree (or the wild olive tree) flowers (Olea europaea L. subsp. europaea var. sylvestris ) from natural ecosystems represented in two Tunisian Parks. The female abortion was evaluated by the percentage of flowers lacking pistil, and male abortion by differential staining for the cytoplasm of pollen grain. Flower abortion was examined and compared for eight oleaster trees in two different natural sites. At the beginning of flowering (the last two weeks of April), the flower numbers ranged from 15 to 26 flowers per inflorescence. However, one month after blossoming, the fruit set ranged from 1 to 3 drupes per inflorescence. Thus, a significant decrease of flowers per inflorescence was observed on all trees. The percentage of flowers without stamens and flowers without pistil per inflorescence ranged from 5.7 to 38.8% and from 4.9 to 88.1%, respectively depending on the oleaster tree. Moreover, abnormal flowers had effect on fruits number per inflorescence. Indeed, the r 2 linear regression values were 0.89 and 0.83, respectively. Therefore, due to the similar flower abnormalities occurring for the olive trees, the transfer of a low rate of abnormal flowers to cultivated olive may improve the crop.

Chemicals profiling and antioxidants activities of Acacia seeds

This study reported investigations on phytochemical screening and antioxidants activities of seeds from seven Acacia species. Storage proteins and mineral contents were determined. The seed extracts of Acacia species were evaluated for their total phenols, flavonoids, carotenoids contents and total antioxidant capacity assessed by 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) and 2,2diphenyl-1- picrylhydrazyl (DPPH) assays. Total protein content ranged from 99.49 ( Acacia cyclops ) to 142.77 ( Acacia cyanaphylla ) mg/g dry weight basis (DW) according to the Acacia species, having an average of 120.41 mg/g DW. The albumin constitutes the major fraction presenting 31.11%, followed by globulin (27.36%), prolamin (22.27%) and glutelin (19.27%). The Acacia seeds were rich in minerals. The total phenolic compounds (TPC) determinate ranged from 154.47 ( A. cyclops ) to 1217.99 ( Acacia horrida ) with an average of 632.40 mg gallic acid equivalents/100 g DW. The total flavonoid contents have an average of 11.21 mg rutin equivalents/100 g DW, and the carotenoids mean is 4.23 mg/kg. The Acacia seed extracts have an antioxidant activity reflected by the ABTS and DPPH tests. The Duncan’s test showed significant difference of proteinic, phenolics, flavonoid and carotenoid contents according to the Acacia species. Therefore, natural components from Acacia seeds could be incorporated as food ingredient, without causing detrimental effects to the foods palatability and the functional ingredients efficacy.

Genetic diversity of Vicia faba L. based on random amplified polymorphic DNA and simple sequence repeat markers

Abstract The genetic diversity of 13 Tunisian faba bean (Vicia faba L.) accessions, and the commercial variety “Aguadulce”, were studied using simple sequence repeats (SSRs) and random amplified polymorphic DNA (RAPD) markers. In comparison to RAPD markers, SSRs showed a higher level of polymorphism and greater information content, as assessed by the expected heterozygosity. One hundred and fourteen bands were amplified using six SSR primer combinations and 376 bands were observed using four RAPD primers. The percentages of polymorphic fragments were 100% and 60.63% for SSR and RAPD markers, respectively. The polymorphism information content, gene diversity and population differentiation test were 0.370, 0.490 and 0.746, respectively, for SSR markers and 0.319, 0.406 and 0.775 for RAPD markers. The correlation coefficients of similarity based on the Mantel test were statistically significant for the both marker systems used, but were higher for SSR data than for RAPD. Dendrogram topologies, conducted separately on polymorphic RAPD and SSR markers, showed minor differences in the grouping of accessions. The dendrogram based on combined RAPD and SSR data sets identified clustering of accessions according to their geographic diffusion. Collectively, these results will aid Tunisian faba bean germplasm management, conservation and breeding.

Fatty Acids, Sterols, Polyphenols, and Chlorophylls of Olive Oils Obtained from Tunisian Wild Olive Trees (Olea europaea L. Var. Sylvestris)

Olive (Olea europaea L.) includes cultivated olive trees (var. europaea) and wild olive trees or oleaster (var. sylvestris) as two botanical varieties. These olive varieties were widely spread in the Mediterranean Region. The aim of this study was to determine fatty acid compositions, sterols, polyphenols, and chlorophylls of oils obtained from 12 wild olive trees from Northern Tunisia. Two dominated oil cultivars in Tunisia (Chétoui and Chemlali) were also used to compare results. The fatty acid methyl ester and the sterol compositions were analyzed using gas-liquid chromatography and thin layer chromatography methods, respectively. The polyphenols and chlorophylls were determined using the calorimetrical method. Results indicated that oils extracted from wild olives displayed good balanced fatty acid compositions, sterols, polyphenols, and chlorophylls. Qualitatively, for wild and cultivated olive oils, the oil has an identical composition, whereas the quantitative variation showed that some wild trees seem to be interesting oil sources as two Tunisian dominated cultivars. The highest oleic acid and polyphenol contents were 71.55% and 537.6 mg/kg of oil found in wild olives (OIch2, OIch1). The β-sitosterol was the major sterolic fraction and ranged from 84.72 to 75.70% according to the wild olives. Consequently, wild olives would be a new future edible olive oil source, as well as commonly cultivated ones.