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Antioxidant properties and stability of betalains in beet and prickly pear juices and in dairy foam

ropriétés antioxydantes et stabilité des bétalaïnes dans les jus de betterave et de figue de barbarie et dans la mousse laitière









1Université Carthage, Ecole Supérieure des Industries Alimentaires de Tunis, 58 Avenue Alain Savary 1003, Tunis, Tunisie.

2Université Tunis EL-Manar, Faculté des Sciences de Tunis, Laboratoire de Chimie Organique Structurale, Tunis, Tunisie.

3Université Sousse, Institut Supérieur des Sciences Agronomiques de Chott Mariem, Sousse- Tunis



Abstract - Betalains are water-soluble plant pigments that are widely used as food colorants, and have a wide range of desirable biological activities. In the present study, juices of beetroot (Beta vulgaris var conditiva L.) and two prickly pear cultivars (Opuntia ficus-stricta L. and Opuntia ficus-indica L.) were evaluated for their betalains stability against various pH conditions (4, 7 and 10) and exposure time of heating at 100°C (5, 20 and 35 minutes). The antioxidant activity of juice was tested by means of two different methods: the 2,2’- azinobis(3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS.+) and the ferric reducing antioxidant power (FRAP) methods. The results showed that the studied juices present a high antioxidant activity associated with a high concentrations of total phenolic compounds, which may have synergistic effects with betalains. Moreover, it showed high concentration of betalains (333.9±47.8; 110.5±5.1; 5.9±0.03 mg/L at 1% DM of juice, respectively) which were stable over a wide pH range (2.8 - 7.0) and were resistant to heating (100oC) up to 20 minutes at acid pH. In cream-cheese mousse, juice addition (20%) improved the sensorial characteristics (Color, odor, smoothness and texture, taste, after taste, overall appreciation). Color retention and antioxidant activity of dyed cheese mousses was influenced by temperature of storage (4, 25 and 37°C). The addition of Opuntia ficus-indica juice showed better color retention (87.8%) at 15 days of storage compared with Opuntia ficus-stricta and beetroot juices (59.9 and 71.7%, respectively). These results confirm the great potential of beetroot and prickly pears as a natural colorant for functional foods

Key words: natural colorant, betalains, beetroot, prickly pear, antioxidant, stability,cream cheese mousse 

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Additonal and unusual records of bleu crabs Portunus segnis and Callinectes sapidus from the northeastern Tunisian waters (Central mediterranean sea)









1Université de Carthage, Institut Supérieur de Pêche et d’Aquaculture de Bizerte, Unité de Recherche: Exploitation des Milieux Aquatiques, Er-Rimel, B.P.15. 7080 Bizerte, Tunisia. Méditerranée Action Nature, 7000, Bizerte, Tunisia.

2Université de Tunis El Manar, Faculté des Sciences de Tunis, Laboratoire de Biodiversité, Biotechnologie et Changement Climatique LR11ES09, 1002 Tunis, Tunisia. Méditerranée Action Nature, 7000, Bizerte, Tunisia.

3Institut National Agronomique de Tunisie, 43, Avenue Charles Nicolle, 1082 Tunis-Tunisie.

4Méditerranée Action Nature, 7000, Bizerte, Tunisia. Université de Tunis El Manar, Faculté des Sciences de Tunis, Laboratoire de Biodiversité, Biotechnologie et Changement Climatique LR11ES09, 1002 Tunis, Tunisia.



Abstract - The present paper deals with recent records of the blue crabs Portunus segnis (Forskål, 1775) and Callinectes sapidus (Rathbun, 1896) from the northeastern coast of Tunisia during September 2019. A total of 10 brachyura individuals including 4 blue swimming crabs and 6 Atlantic blue crabs were collected in shallow waters on sandy and muddy bottom by fishermen using gillnets and trammel nets from Bizerte and Ghar El Melh Lagoons. All morphometric measurements of these two species were studied. The difference between morphometric characters for P. segnis and C. sapidus were also examined. The concomitant occurrence of these two crab species will have probably unfavourable consequences for these restricted areas.

Key words: Biodiversity, Invasion, Brachyura, Tunisian Lagoons, Climate change, Socio-economic impacts.

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Characterization of sheep production systems in the mountainous and forest areas of Northern Tunisia: Alternative ways to improve their productivity

Mohamed-Brahmi Aziza1

Jemmali Bayrem2

Choucene Wiem3

Saidani Faiçal2


1Sustainability Laboratory for Production Systems in the North West Region. Higher School of Agriculture of Kef

2LR13AGR02, ADIPARA Lab, Higher School of Agriculture of Mateur, Carthage University, Tunisia

3Department of Animal Sciences, National Institute of Agronomy of Tunisia, Tunis, Tunisia



Abstract - The overall objective of this study is to characterize the sheep production systems in mountainous and forest areas located in Northern Tunisia and to identify alternative ways to improve their productivity. A total of 81 farmers holding 1672 ewes and 73 rams were interviewed. Surveyed farms are in humid and semi-arid zones in northern Tunisia. Results analysis showed that the flock’s reproductive performances are relatively low. Indeed, the average age at first mating of either females or males is late. It is respectively about 19.3 (2.3) and 20.6 (4.2) months. Similarly, the fertility and fecundity rates are respectively 87.3 (6.6) % and 102.8 (9.5) %. Statistical analysis demonstrates that these parameters were significantly (p<0.05) influenced by the land area, the ewes’ age and the flushing technique. Best results were recorded in areas with significant forage potential, among young farmers who are more receptive than the elderly and where flocks’ feeding is well mastered. Due to a lack of funds, preventing them to buy concentrate feed, 83% of the surveyed farmers do not practice lambs' fattening. The animals' sale is carried out at an early age (7.5 months). An efficient extension program associated with adequate supervision and monitoring of sheep farmers is needed to better assimilate the breeding techniques and valorize the mountains’ pastures. Organization of farmers into associations may facilitate the establishment of better development actions in these zones and better use of best breeding practices.

Key words: Sheep, Forests, Mountains, Productivity, Tunisia.

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This article is published under license to Journal of New Sciences. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

CC BY 4.0