Francisco José Santiago Medina - Academia.edu (original) (raw)

Papers by Francisco José Santiago Medina

Une alternative aux produits industriels de type phenol ou resorcinol peut etre des tanins ou de ... more Une alternative aux produits industriels de type phenol ou resorcinol peut etre des tanins ou de la lignine. Les deux sont des polyphenols naturels, le tanin est extrait de differentes parties de plantes, tandis que la lignine est habituellement obtenue comme sous-produit dans les industries papetieres. Ces deux produits sont la base principale sur laquelle j’ai travaille pendant le developpement de cette these. Dans une premiere partie, une etude de caracterisation et de differenciation entre differents tannins ayant la meme origine mais que presentent un comportement different lorsqu'ils sont utilises dans la meme application dans les memes conditions a ete effectuee. Cette etude met en evidence la GPC comme technique fondamentale pour la differenciation des tanins de quebracho sulfites. D'autre part, les interactions entre differentes substances avec du tanin et de la lignine ont ete etudiees. Comme l’etude de la reaction entre les diamines (telles que l'hexamethylene...

Scientific Reports, 2020

In order to promote convenient strategies for the valorization of Aucoumea klaineana Pierre (Okou... more In order to promote convenient strategies for the valorization of Aucoumea klaineana Pierre (Okoume) plywood and sawmill wastes industry in the fields of adhesives and composites, the total phenolic content of Okoume bark, sapwood and heartwood was measured. The molecular structure of tannins extracted from the bark was determined by Matrix Assisted Laser Desorption/Ionization Time-Of-Flight (Maldi-ToF) mass spectrometry and Fourier transform infrared spectroscopy (FTIR). The total phenolic content displayed significant difference (p = 0.001) between the bark, sapwood and heartwood which decreased as follows: 6 ± 0.4, 2 ± 0.8 and 0.7 ± 0.1% respectively. The pro-anthocyanidins content was also significantly different (p = 0.01) among the three wood wastes, and the bark was the richest in condensed tannins (4.2 ± 0.4%) compared to the sapwood (0.5 ± 0.1%) and heartwood (0.2 ± 0.2%). Liquid chromatography coupled mass spectroscopy (LC-MS) and Maldi-ToF analysis of the bark showed for ...

Holzforschung, 2020

This paper deals with an original and non-biocidal chemical treatment consisting of a vacuum/pres... more This paper deals with an original and non-biocidal chemical treatment consisting of a vacuum/pressure impregnation step of beech wood with a water-borne mixture made from heat-activated condensation of succinic anhydride (SA) and glycerol (G). Chemical structures of adducts were established using matrix-assisted laser desorption ionization time-of-flight mass spectroscopy (MALDI-TOF) investigations. Beech wood was impregnated and cured in order to inducein situpolymerization of glycerol/succinic adducts (GSA) in the cell walls, leading to the formation of polyglycerol succinate (PGS) polyester. Various treatment conditions were investigated depending on the duration (6–72 h) and curing temperature (103–160°C). Weight percent gains (WPGs) ranging between 40 and 60% were obtained. Attenuated total reflectance-middle infrared spectroscopy (ATR-MIR) and carbon-13 nuclear magnetic resonance (13C-NMR) spectroscopy confirmed polyester formation. A curing temperature of 160°C was found to b...

Industrial Crops and Products, 2017

Barks are available as waste material and by-product of wood industry. They have been reported to... more Barks are available as waste material and by-product of wood industry. They have been reported to contain interesting molecules and show some bioactivity such as antioxidant and antifungal. This study aimed at evaluating the amounts of extractives in Acacia mangium (acacia), Paraserianthes falcataria (sengon) and Swietenia mahagoni (mahoni) barks, to evaluate their extractive contents and the presence of potential valuable molecules. The extraction method used soxhlet with four different solvents. Antioxidant activity assays were carried out using methyl linoleate and 2,2-diphenyl-1-picrilhidrazyl (DPPH) and the antifungal activity was determinate by fungal growth inhibitions assays. 5.3%-18.5% extraction yields were obtained. All acetone and toluene ethanol extracts show high antioxidant activity by DPPH. The highest antioxidant value obtained by DPPH was obtained for mahoni bark acetone extract with 3.9 mg/L of EC50, followed by mahoni bark toluene ethanol 6.8 mg/L, acacia bark acetone 7 mg/L, and acacia bark toluene ethanol extract 7.4 mg/L. Sengon bark extracts had the greatest antifungal activity inhibition. The greatest antioxidant and antifungal activity were obtained with phenolic compounds which were contained in the extracts.

Wood Science and Technology, 2020

Aucoumea klaineana Pierre (Okoume) tannins were extracted by an artisanal maceration method in th... more Aucoumea klaineana Pierre (Okoume) tannins were extracted by an artisanal maceration method in the presence of acetone/water used as solvent. The tannins obtained from the sapwood and heartwood and characterized by Maldi-ToF and FTIR did not present any differences regarding their type of oligomers. Tannins were more abundant in sapwood than in heartwood, but in both of them, fisetinidin and gallocatechin were the main monomers of condensed tannin. A low content of trihydroxyflavan monomer was identified, whereas non-glycosylated condensed tannins up to seven oligomers were found in high content in Okoume. These results, which revealed for the first time the chemical structure of Okoume condensed tannins showed the presence of a glycosylated condensed tannin series up to six carbohydrate residues attached to 2xgallocatechin-1xcatechin flavonoids.

Une alternative aux produits industriels de type phenol ou resorcinol peut etre des tanins ou de ... more Une alternative aux produits industriels de type phenol ou resorcinol peut etre des tanins ou de la lignine. Les deux sont des polyphenols naturels, le tanin est extrait de differentes parties de plantes, tandis que la lignine est habituellement obtenue comme sous-produit dans les industries papetieres. Ces deux produits sont la base principale sur laquelle j’ai travaille pendant le developpement de cette these. Dans une premiere partie, une etude de caracterisation et de differenciation entre differents tannins ayant la meme origine mais que presentent un comportement different lorsqu'ils sont utilises dans la meme application dans les memes conditions a ete effectuee. Cette etude met en evidence la GPC comme technique fondamentale pour la differenciation des tanins de quebracho sulfites. D'autre part, les interactions entre differentes substances avec du tanin et de la lignine ont ete etudiees. Comme l’etude de la reaction entre les diamines (telles que l'hexamethylene...

Scientific Reports, 2020

In order to promote convenient strategies for the valorization of Aucoumea klaineana Pierre (Okou... more In order to promote convenient strategies for the valorization of Aucoumea klaineana Pierre (Okoume) plywood and sawmill wastes industry in the fields of adhesives and composites, the total phenolic content of Okoume bark, sapwood and heartwood was measured. The molecular structure of tannins extracted from the bark was determined by Matrix Assisted Laser Desorption/Ionization Time-Of-Flight (Maldi-ToF) mass spectrometry and Fourier transform infrared spectroscopy (FTIR). The total phenolic content displayed significant difference (p = 0.001) between the bark, sapwood and heartwood which decreased as follows: 6 ± 0.4, 2 ± 0.8 and 0.7 ± 0.1% respectively. The pro-anthocyanidins content was also significantly different (p = 0.01) among the three wood wastes, and the bark was the richest in condensed tannins (4.2 ± 0.4%) compared to the sapwood (0.5 ± 0.1%) and heartwood (0.2 ± 0.2%). Liquid chromatography coupled mass spectroscopy (LC-MS) and Maldi-ToF analysis of the bark showed for ...

Holzforschung, 2020

This paper deals with an original and non-biocidal chemical treatment consisting of a vacuum/pres... more This paper deals with an original and non-biocidal chemical treatment consisting of a vacuum/pressure impregnation step of beech wood with a water-borne mixture made from heat-activated condensation of succinic anhydride (SA) and glycerol (G). Chemical structures of adducts were established using matrix-assisted laser desorption ionization time-of-flight mass spectroscopy (MALDI-TOF) investigations. Beech wood was impregnated and cured in order to inducein situpolymerization of glycerol/succinic adducts (GSA) in the cell walls, leading to the formation of polyglycerol succinate (PGS) polyester. Various treatment conditions were investigated depending on the duration (6–72 h) and curing temperature (103–160°C). Weight percent gains (WPGs) ranging between 40 and 60% were obtained. Attenuated total reflectance-middle infrared spectroscopy (ATR-MIR) and carbon-13 nuclear magnetic resonance (13C-NMR) spectroscopy confirmed polyester formation. A curing temperature of 160°C was found to b...

Industrial Crops and Products, 2017

Barks are available as waste material and by-product of wood industry. They have been reported to... more Barks are available as waste material and by-product of wood industry. They have been reported to contain interesting molecules and show some bioactivity such as antioxidant and antifungal. This study aimed at evaluating the amounts of extractives in Acacia mangium (acacia), Paraserianthes falcataria (sengon) and Swietenia mahagoni (mahoni) barks, to evaluate their extractive contents and the presence of potential valuable molecules. The extraction method used soxhlet with four different solvents. Antioxidant activity assays were carried out using methyl linoleate and 2,2-diphenyl-1-picrilhidrazyl (DPPH) and the antifungal activity was determinate by fungal growth inhibitions assays. 5.3%-18.5% extraction yields were obtained. All acetone and toluene ethanol extracts show high antioxidant activity by DPPH. The highest antioxidant value obtained by DPPH was obtained for mahoni bark acetone extract with 3.9 mg/L of EC50, followed by mahoni bark toluene ethanol 6.8 mg/L, acacia bark acetone 7 mg/L, and acacia bark toluene ethanol extract 7.4 mg/L. Sengon bark extracts had the greatest antifungal activity inhibition. The greatest antioxidant and antifungal activity were obtained with phenolic compounds which were contained in the extracts.

Wood Science and Technology, 2020

Aucoumea klaineana Pierre (Okoume) tannins were extracted by an artisanal maceration method in th... more Aucoumea klaineana Pierre (Okoume) tannins were extracted by an artisanal maceration method in the presence of acetone/water used as solvent. The tannins obtained from the sapwood and heartwood and characterized by Maldi-ToF and FTIR did not present any differences regarding their type of oligomers. Tannins were more abundant in sapwood than in heartwood, but in both of them, fisetinidin and gallocatechin were the main monomers of condensed tannin. A low content of trihydroxyflavan monomer was identified, whereas non-glycosylated condensed tannins up to seven oligomers were found in high content in Okoume. These results, which revealed for the first time the chemical structure of Okoume condensed tannins showed the presence of a glycosylated condensed tannin series up to six carbohydrate residues attached to 2xgallocatechin-1xcatechin flavonoids.