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Antioxidant contents and activities of different extracts from four Tunisian pomegranate peels, locally called "Acide", "Gabsi", "Nebli" and "Tounsi", were studied. Peels samples were extracted with three solvents (water, ethanol and acetone). For each extract, the total phenol contents and antioxidant activity were evaluated. The highest values of polyphenol, tannins, flavonoids and anthocyanins were recorded in the acetone extract of Acide ecotype with 304.6 mg gallic acid equivalent/g; 292.23 mg gallic acid equivalent/g; 15.46 mg Quercetin/g and 54.51 mg cy-3-glu/100 g, respectively. The acetone extract of Acide ecotype also showed the highest free radical-scavenging and reducing power activity compared to other extracts. Besides, the phytochemical analysis by LC-MS/MS revealed a high content of ellagitannins with punicalagin and punicalagin derivatives as the major compounds that might be responsible for promising antioxidant activity of pomegranate peel extracts. Two compounds (Castalagin derivative and Galloyl-bis-HHDP-hex derivative) were detected only in "Acide" ecotype in important contents.

The composition of pomegranate peel, the main by-product during pomegranate processing, and some of the characteristics of the water-soluble pectins were investigated. Four tunisian pomegranate peels were subjected to hot aqueous extractions (86°C, 80min, 20mM nitric acid). Pomegranate peels yielded between 6.8% and 10.1% pectins. The extracted pectins were low methylated and were characterized by the predominance of homogalacturonan regions. Principal component analysis applied on FT-IR spectral data in the region between 4000 and 650cm(-1) differentiated the samples according to their degree of methylation. At pH 3, in the presence of 0.7% pectin, all solutions showed a rapid gel formation with G'>G″. With decreasing temperature from 90°C to 10°C, G' increased to reach a plateau at 10°C. The variation in the pectin gel formation between varieties was attributed to difference in pectin characteristics particularly the hydrodynamic volume and the neutral sugar content.

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The proximale composition of Aleppo pine (Pinus halepensis Mill.) seeds cultivated in Bizerta (Tunisia) were investigated for their fatty acid composition, and their thermal and physical properties of lipid fraction. The proximate analysis of pine seeds showed the following composition (on a dry-weight basis): protein 22.7%, oil 43.3%. ash 8.3% and total carbohydrate 25.7%. Potassium. magnesium and calcium were the predominant mineraI elements present in the seeds and reached, together, about 1%. Oleic and linoleic acids were the major unsaturated fatty acids (27.3 and 48.8%, respectively), while the main saturated one was palmitic acid (8.75%). Myristic. rnyristoleic. palmitoleic, margaric, margaroleic, stearic, linolenic, arachidic, eicosenoic, eicosadienoic eicosatrienoic behenic and lignoceric acids were also detected. Thermal profile of Pinus halepensis Mill. seed oil, determined by its DSC melting curve, showed that the en tire liquefaction of the Aleppo pine seed oil occurs at -8°C. CieLab colour parameters (L", a*. b*). oxidative stability by Rancimat test and viscosity were also determined. Physicochernical properties of the oil include: saponification nurnber J 90, peroxide value 3.18. iodine index 1J 7, and a low acidity of 0.61 %. Results suggested that the production of oil from Pinus halepensis seeds could provide a potential use in food, pharmaceutical, cosmetics and other non-food industries.

--Introduction. Despite their high nutritional value, by-products of dates are valueless in Tunisia, an important date-producing country. Our study aimed at testing a method for recovering these products by means of extraction, starting from a date paste, of a clarified drink. Materials and methods. The process of pulp extraction adopted was inspired by a traditional method. A rough solution obtained from the dilution of date paste was treated with enzymes (pectinases and cellulases) and by tangential microfiltration. The chemical composition, physico-chemical characteristics and rheological characteristics of the clarified drink obtained were determined. Results and discussion. The extracted rough solution has a high sugar content. The use of both microfiltration and enzymatic treatment resulted in a juice that has little acid content, with relatively low viscosity and turbidity and with a flow behaviour comparable to that of any other fruit juice. Conclusion. By-products of dates can be transformed, by the means of the usual processes, into a pleasant and marketable drink.

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