Hajer Trabelsi

Gas chromatography-mass spectrometry screening for phytochemical 4-desmethylsterols accumulated during development of Tunisian peanut kernels (Arachis hypogaea L.).

4-Desmethylsterols, the main component of the phytosterol fraction, have been analyzed during the development of Tunisian peanut kernels ( Arachis hypogaea L.), Trabelsia (AraT) and Chounfakhi (AraC), which are monocultivar species, and Arbi (AraA), which is a wild species, by gas chromatography-mass spectrometry. Immature wild peanut (AraA) showed the highest contents of beta-sitosterol (554.8 mg/100 g of oil), campesterol (228.6 mg/100 g of oil), and Delta(5)-avenasterol (39.0 mg/100 g of oil) followed by peanut cultivar AraC with beta-sitosterol, campesterol, and Delta(5)-avenasterol averages of 267.7, 92.1, and 28.6 mg/100 g of oil, respectively, and similarly for AraT 309.1, 108.4, and 27.4 mg/100 g of oil, respectively, were found. These results suggest that, in immature stages, phytosterol contents can be important regulator factors for the functional quality of peanut oil for the agro-industry chain from plant to nutraceuticals.

Analysis of pecan nut (Carya illinoinensis) unsaponifiable fraction. Effect of ripening stage on phytosterols and phytostanols composition

Changes in 4-desmethylsterol, 4-monomethylsterol, 4,4-dimethylsterol and phytostanol composition were quantitatively and qualitatively investigated during the ripening of three varieties of Tunisian-grown pecan nuts (Mahan, Moore and Burkett). These components have many health benefits, especially in lowering LDL-cholesterol and preventing heart disease. The phytosterol composition of whole pecan kernel was quantified by Gas Chromatography-Flame Ionisation Detection (GC-FID) and identified by Gas Chromatography-Mass Spectrometry (GC-MS). Fifteen phytosterols and one phytostanol were quantified. The greatest amount of phytosterols (2852.5mg/100g of oil) was detected in Mahan variety at 20 weeks after the flowering date (WAFD). Moore had the highest level of phytostanols (7.3mg/100g of oil) at 20 WAFD. Phytosterol and phytostanol contents showed a steep decrease during pecan nut development. Results from the quantitative characterisation of pecan nut oils revealed that β-sitosterol, Δ5-avenasterol, and campesterol were the most abundant phytosterol compounds at all ripening stages.

Triacylglycerols and aliphatic alcohols from fruits of three Tunisian Pistacia lentiscus populations.

BACKGROUND The search for other sources of vegetable oils by the exploitation and the enhancement of other oil plants will be needed to meet the demands of the international market. This study aims to determine the triacylglycerol (TAG) molecular species and aliphatic alcohol compositions of unexploited fruits of three Tunisian Pistacia lentiscus (lentisc) populations from the Korbous, Tebaba and Rimel areas of Tunisia. RESULTS Results show that the content of total TAG varies from 738.32 mg g(-1) of total lipid in the Tebaba population to 981.15 mg g(-1) of total lipid in the Korbous population. Furthermore, 14 species of TAG were detected in the three studied populations. In addition, 13 aliphatic compounds were identified and classified into two groups: (1) aliphatic alcohols with fewer than 20 carbon atoms (hexadecanol, heptadecanol, (Z)-octadec-9-en-1-ol, octadecanol and nonadécanol); and (2) the policosanol group (eicosenol, docosenol, docosanol tetracosanol, hexacosanol octacosanol and triacontanol). The Tebaba population showed a distinct composition compared to Korbous and Rimel where heptadecanol is the major compound. CONCLUSION Quantitatively, the most abundant TAG species are those constituted by palmitic, oleic and/or linoleic acid. Furthermore, the significant difference observed at the oil composition is associated with a remarkable station effect.

Changes in the triacylglycerol content of flaxseeds during development using liquid chromatography- atmospheric pressure photoionization-mass spectrometry (LC-APPI-MS)

Changes in the composition of triacylglycerols (TAGs) of three varieties of flaxseeds (H52, O116 and P129) during development were investigated using non-aqueous reversed phase liquid chromatography coupled to atmospheric pressure photoionization-mass spectrometry (LC-APPI-MS). 17 species of triacylglycerols were found and their fatty acyl composition was confirmed by fragment ions in the mass spectra. The major forms observed were LnLnLn, LnLLn, LnOLn, LLLn, LnLnP, OOLn and OLLn. The highest change in these compounds occurred in the early development period for most TAGs. The most active period of triacylglycerol synthesis was between 7 and 35 days after flowering (DAF). LnLnLn exhibited the most significant increase during flaxseed development. At maturity, similar TAG profiles were found for the three samples.

Effect of seed maturation stages on physical properties and antioxidant activity in flaxseed ( Linum usitatissimum L.)

The changes in flaxseed constituents at different stages of maturity are reported. The physical properties and antioxidant activity of flaxseed oil during flaxseed development have been evaluated. Continuous decrease in total polyphenol content during flaxseed development. All the results showed no significant differences between HPLC-MS and TLC for quantitative determination of phospholipids classes. The fatty acid compositions of individual phospholipids were also reported. The antioxidant activity of oilseed was assessed by means of 2, 2-diphenyl-1-picryl-hydrazyl (DPPH) radical scavenging assay. The test demonstrated that the antioxidant activity of the flaxseed oil was found to be harvesting time-dependant.

Effects of Adding Different Proportions of Sunflower Seeds on Fatty AcidComposition of Chicken Tissues

Poultry meat becomes an essential part of our nutrition, our aim is to optimize poultry meat quality to obtain more healthy results. Because of its rich composition of desired fatty acids, we chose sunflower seeds (SS) as chicken’s food to search for the best proportion to obtain the best meat composition. A basal diet is given to chickens, with proportions of 25%, 50%, and 75% of sunflower seeds, respectively for each group. The results were very adequate: the more we add SS in chicken’s meal, the more its composition is expressed in chickens tissues. So, monounsaturated fatty acids (MUFA) were the major FA, decrease for the favor of polyunsaturated fatty acids (PUFA) in all tissues, linoleic acid become the major FA taking the place of Oleic Acid. Saturated fatty acids (SFA) become, fortunately, lower; it’s a target to low the content of SFA, since they have been associated with several human diseases.