Improvement of the composition of Tunisian myrtle berries (Myrtus communis L.) alcohol extracts

Different extracts from myrtle berries were obtained using alcohol-water mixtures as an extraction medium in the range of 60-90% (v/v) to study the extraction efficiency in the preparation of myrtle liqueur. Flavonoids and anthocyanins were identified by high-performance liquid chromatography (HPLC) coupled with electrospray mass spectrometry and quantified during the maceration period by HPLC coupled with ultraviolet/visible detection. The antioxidant activity was tested by the 2,2-diphenyl-1-picrylhydrazyl assay. Dry matter, pH, and color parameters (L, a, b) were also analyzed. At the end of the maceration period, EE80 showed better anthocyanins stability and the highest total antioxidant activity (87.5%). These results suggest that the use of ethanol 80% provides the extract with the best characteristics for liqueur preparation. The present study contributes significantly to increase the marketing appeal of myrtle berries.     

Structures,Properties and Applications of Alginates

Alginate is a hydrocolloid from algae, specifically brown algae, which is a group that includes many of the seaweeds, like kelps and an extracellular polymer of some bacteria. Sodium alginate is one of the best-known members of the hydrogel group. The hydrogel is a water-swollen and cross-linked polymeric network produced by the simple reaction of one or more monomers. It has a linear (unbranched) structure based on d-mannuronic and l-guluronic acids. The placement of these monomers depending on the source of its production is alternating, sequential and random. The same arrangement of monomers can affect the physical and chemical properties of this polysaccharide. This polyuronide has a wide range of applications in various industries including the food industry, medicine, tissue engineering, wastewater treatment, the pharmaceutical industry and fuel. It is generally recognized as safe when used in accordance with good manufacturing or feeding practice. This review discusses its application in addition to its structural, physical, and chemical properties.     

Structural Characterization and Rheological and Antioxidant Properties of Novel Polysaccharide from Calcareous Red Seaweed

A novel sulfated xylogalactan (JASX) was extracted and purified from the rhodophyceae Jania adhaerens. JASX was characterized by chromatography (GC/MS-EI and SEC/MALLS) and spectroscopy (ATR-FTIR and ¹H/¹³C NMR) techniques. Results showed that JASX was constituted by repeating units of (→3)-β-d-Galp-(1,4)-3,6-α-l-AnGalp-(1→)_n and (→3)-β-d-Galp-(1,4)-α-l-Galp-(1→)_n substituted on O-2 and O-3 of the α-(1,4)-l-Galp units by methoxy and/or sulfate groups but also on O-6 of the β-(1,3)-d-Galp mainly by β-xylosyl side chains and less by methoxy and/or sulfate groups. The M_w, M_n, Đ, [η] and C* of JASX were respectively 600 and 160 kDa, 3.7, 102 mL.g⁻¹ and 7.0 g.L⁻¹. JASX exhibited pseudoplastic behavior influenced by temperature and monovalent salts and highly correlated to the power-law model and the Arrhenius relationship. JASX presented thixotropic characteristics, a gel-like viscoelastic behavior and a great viscoelasticity character. JASX showed important antioxidant activities, outlining its potential as a natural additive to produce functional foods.     

The high prolificacy of D’man sheep is associated with the segregation of the FecLL mutation in the B4GALNT2 gene

Mutations in the FecL locus are associated with large variation in ovulation rate and litter size in the French Lacaune sheep breed. It has been shown that the B4GALNT2 gene within the FecL locus is most likely responsible for the high fecundity in the French breed. In this study, we have highlighted the segregation of the FecL^L mutation within the B4GALNT2 gene in North African sheep breeds and notably in the highly prolific D'man breed. Genotyping of a sample of 183 Tunisian D'man individuals revealed a high frequency (0.65) of the prolific allele FecL^Lwhich was attributed to the adoption of a decades‐old breeding strategy based on the selection of ewe lambs born from large litter size. Homozygous LL ewes showed a significantly increased litter size compared to heterozygous and non‐carrier ewes (FecL^L/FecL^L = 2.47 ± 0.09 vs. FecL^L/FecL⁺ = 2.23 ± 0.09, p < 0.05 and FecL⁺/FecL⁺ = 1.93 ± 0.18, p < 0.01). The presence of the FecL^Lpolymorphism in both D'man and Lacaune breeds argues for an ancestral origin of this mutation and brings an answer to the old question of the genetic determinism of the extreme prolificacy of the D'man ewes. The results of this study can help to establish planned genotype‐based mating allowing both higher profit for the breeders and an optimal management of the FecL^L mutation in D'man sheep populations.     

Molecular and Structural Characterizations of Lipases from Chlorella by Functional Genomics

Microalgae have been poorly investigated for new-lipolytic enzymes of biotechnological interest. In silico study combining analysis of sequences homologies and bioinformatic tools allowed the identification and preliminary characterization of 14 putative lipases expressed by Chlorella vulagaris. These proteins have different molecular weights, subcellular localizations, low instability index range and at least 40% of sequence identity with other microalgal lipases. Sequence comparison indicated that the catalytic triad corresponded to residues Ser, Asp and His, with the nucleophilic residue Ser positioned within the consensus GXSXG pentapeptide. 3D models were generated using different approaches and templates and demonstrated that these putative enzymes share a similar core with common α/β hydrolases fold belonging to family 3 lipases and class GX. Six lipases were predicted to have a transmembrane domain and a lysosomal acid lipase was identified. A similar mammalian enzyme plays an important role in breaking down cholesteryl esters and triglycerides and its deficiency causes serious digestive problems in human. More structural insight would provide important information on the enzyme characteristics.     

Lipolytic activity levels and colipase presence in digestive glands of some marine animals

Studies on the digestive secretions in aquatic animals can elucidate certain aspects of their nutritive physiology. The aim of the present study was to compare the digestive lipase and phospholipase activities in ten marine species belonging to four classes following the taxonomic classification of marine organisms. All aquatic digestive tissues tested are equipped with lipase and phospholipase activities, assuming the hydrolysis of fat-rich food. The lipolytic activities determined in the pancreases of cartilaginous fishes were greater than those in bony fishes, molluscs and crustaceans. This finding might be explained by the strong digestive utilization of fat-rich macronutrients by these carnivorous fishes. A trend of activities and stabilities at different pH and temperatures for crude lipases and phospholipases from these aquatic animals suggests that the optimum pH and temperature for marine lipases are species dependent. Interestingly, the sardine caecal lipase and phospholipase were found to be mostly stable in a broad range of acidic pH values. The maximum activities of lipolytic enzymes from the hepatopancreases of Hexaplex trunculus (molluscs) and Carcinus mediterranus (crustaceans) were found to be 50 and 60?°C, respectively, whereas the optimal temperature of lipolytic enzymes for the other species was classically around 40?°C. Thermoactivity of molluscs' lipolytic preparations makes them potential candidates in industrial applications. Among digestive glands studied, only pancreas (cartilaginous fish) contained the classically known colipase. Regarded as the most primitive living jawed vertebrates, cartilaginous fishes represented by sharks and rays could be considered as the oldest vertebrates possessing a complex digestive system like that of mammals.     

Chemometric Multivariate Analyses of Kernel Biometric Techniques and Shell Morphological Attributes for Analyzing Pistacia vera L. Genotypes Variability

In this study, the corresponding correlations, interdependencies, and relationships of nine traits of pistachio (Pistacia vera L.) kernels were established. Here, the percentage of dehiscent shells, shell homogeneity, shell apex, position of suture opening, suture opening, number of pistachio kernels/100?g, (length/width) pistachio kernel ratio, pistachio kernel flavour and fat content of pistachio kernel were studied.

The evaluation of experimental data was performed by applying a chemometric approach: Principal Component Analysis (PCA), Bayesian Networks method and Network Meta-Analysis. In this regard, based on PCA the first principal component of shell and kernel had high loadings for shell homogeneity. By using Bayesian Networks method, dendrogram of selected pistachio varieties demonstrate a high similitude existing between varieties. Furthermore, the of shell and kernel dendrogram of studied pistachio varieties demonstrated that all studied accessions could be separated into four distinct groups. Based on cluster analysis, a detailed comparison between the varieties demonstrated that the accession named ‘KERMAN’ showed a significant similarity with the Tunisian genotype ‘ELGUETAR’. In this line, Network Meta-Analysis exhibited the different interdependencies between morphological parameters, and the hierarchical clustering via heat maps displayed relationships between studied factors.

These results showed a potential use of desired characteristics at least in some infra-specific studies in Pistacia vera L. The findings of this study will help plant growers by highlighting hidden and eventual relationships between Pistacia vera L. varieties.