Naima R.,Hassan II University |
Oumam M.,Hassan II University |
Hannache H.,Hassan II University |
Sesbou A.,ENFI |
And 4 more authors.
Industrial Crops and Products | Year: 2015
The performance of three techniques, conventional maceration at room temperature, infusion and microwave assisted extraction, was evaluated to extract polyphenols, condensed and hydrolysable tannins from Moroccan barks of Acacia mollissima. A comparison of these methods was performed using colorimetric assays. For each technique, the effect of extraction conditions on the yield extracts was evaluated. The variables studied are: solvent nature, barks ages, time extraction, power extraction and heat interaction with solvent nature and barks ages. This study proved that the choice of solvent extraction was a relation of the extraction method used and the extractible nature (polyphenols, condensed or hydrolysable tannins). Methanol was the best solvent to extract tannin and polyphenols using maceration at room temperature, and ethanol was the best for infusion at 60. °C. Microwave was more selective to extract polyphenols and tannins under extraction solvent used. Highest polyphenols contents was obtained using methanol. For condensed and hydrolysable tannins, the highest were obtained using water. The polyphenols contents extracted using maceration was closed to the yield obtained with microwave, 354. mg. GAE/g bark, 442. mg. GAE/g bark, respectively. This study proved the pertinence of traditional methods to extract polyphenols and tannins compared to the new extraction method (microwave). The best polyphenols yields, condensed and hydrolysable tannins were obtained by microwave followed by the yield obtained by maceration and finally the yield obtained by infusion. © 2015 Elsevier B.V.
Saad H.,CNRS Institute of Chemistry |
Charrier-El Bouhtoury F.,EPCP IPREM |
Pizzi A.,University of Lorraine |
Rode K.,Deutsches Kunststoff - Institute |
And 2 more authors.
Industrial Crops and Products | Year: 2012
The phenolic extractives of pomegranate peels from various cultivars were studied. The total polyphenols, the condensed and the hydrolyzable tannin contents were analyzed for 4 Tunisian pomegranate cultivars (Mekki, Chelfi, Gabsi, Jbeli). Matrix assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry was used to examine the tannin oligomer structure. Analysis shows fluctuating rates of total polyphenols, condensed and hydrolyzable tannins between the different cultivars, but they are considered higher than those found with other plants. Flavonoid oligomers up to pentamers and some hexamers were detected in MALDI-TOF positive ion mode analysis. In the negative ion mode analysis the majority of the oligomers have glucose residues linked to them. © 2012 Elsevier B.V.
Hamza S.,CNRS Institute of Chemistry |
Saad H.,CNRS Institute of Chemistry |
Charrier B.,EPCP IPREM |
Ayed N.,CNRS Institute of Chemistry |
Charrier-El Bouhtoury F.,EPCP IPREM
Industrial Crops and Products | Year: 2013
Alfa leaves, rush stems, palm leaflets and date palm wood are important renewable raw materials available in Tunisia where they are commonly used in handcrafts (like basketwork and carpets for example). To add value to these plants by using them as a potential reinforcement in so called natural fiber composites a better understanding of their physico-chemical properties is needed. As an application, we have studied the possibility of using alfa leaves, rush stems, palm leaflets as reinforcement in building materials trying to replace commercial fibers. Thus, the effect of hygroscopic parameters were studied and showed different behaviors depending on the raw material origin and morphology. Palm tree stipe is more sensitive than other fibers concerning the impregnation yield and saturation degree. The chemical composition was established. The contents of holocellulose and lignin were comparable to those found with fibers and wood (softwood and hardwood). Extractives in different solvents and ash contents are relatively high. Extractives from fibers are similar in their values and correspond also to those of palm tree stipe, but they are higher than those of hardwood. About ash contents, the same observation was found.Flexural strength of Tunisian fiber-plaster based composites show a maximum of resistance between 4.8 and 5.6. MPa with a strengthening rate of 5% in comparison with commercial plant fiber that presents a bending strength of 4.8. MPa for also a strengthening rate of 5%. © 2013 Elsevier B.V.