Study of color alterations in European oak wood during vacuum drying
An analysis of the mechanisms of discoloration in oak wood during plain vacuum drying allowed us to identify three mechanisms of discoloration. These include degradation of hemicelluloses, oxidation of tannins and release of volatile organic components. We studied the alterations to the material by...
| Hoofdauteurs: | , , , |
|---|---|
| Formaat: | Online |
| Taal: | fra |
| Gepubliceerd in: |
Instituto de Ecología, A.C.
2016
|
| Online toegang: | https://myb.ojs.inecol.mx/index.php/myb/article/view/1329 |
| _version_ | 1799769291319410688 |
|---|---|
| author | Sandoval Torres, Sadoth Jomaa, Wahbi Marc, Françoise Puiggali, Jean-Rodolphe |
| author_facet | Sandoval Torres, Sadoth Jomaa, Wahbi Marc, Françoise Puiggali, Jean-Rodolphe |
| author_sort | Sandoval Torres, Sadoth |
| collection | MYB |
| description | An analysis of the mechanisms of discoloration in oak wood during plain vacuum drying allowed us to identify three mechanisms of discoloration. These include degradation of hemicelluloses, oxidation of tannins and release of volatile organic components. We studied the alterations to the material by measuring color changes, determining the antioxidant potential and analyzing the surface using infrared spectroscopy. Three vacuum drying conditions were applied (46 °C, 61 °C and 70 °C at pressure levels of 6 kPa - 10 kPa (60 mBar - 100 mBar). Despite the difficulty of studying and establishing the role of the extractives in changes in wood color during vacuum drying, we found relationships between the drying temperature, antioxidant potential and C=O peak intensities in the infrared spectra. By the oxidation and hydrolysis reactions, certain chemical compounds are modified. In addition, the presence of water and air accelerates the formation of organic acids (acetic acid). These acids catalyze the hydrolysis of hemicelluloses. The increase in color saturation and brightness can be related to the thermal degradation of extractives (mainly the ellagitannins). |
| format | Online |
| id | oai:oai.myb.ojs.inecol.mx:article-1329 |
| institution | Madera y Bosques |
| language | fra |
| publishDate | 2016 |
| publisher | Instituto de Ecología, A.C. |
| record_format | ojs |
| spelling | oai:oai.myb.ojs.inecol.mx:article-13292022-11-30T05:25:08Z Study of color alterations in European oak wood during vacuum drying Étude des altérations de la couleur du bois de Chêne lors du séchage sous vide discontinu Sandoval Torres, Sadoth Jomaa, Wahbi Marc, Françoise Puiggali, Jean-Rodolphe European oak wood color changes thermal degradation ellagitannins vacuum drying Bois de chêne Européen changement de la couleur dégradation thermique éllagitanins séchage sous vide An analysis of the mechanisms of discoloration in oak wood during plain vacuum drying allowed us to identify three mechanisms of discoloration. These include degradation of hemicelluloses, oxidation of tannins and release of volatile organic components. We studied the alterations to the material by measuring color changes, determining the antioxidant potential and analyzing the surface using infrared spectroscopy. Three vacuum drying conditions were applied (46 °C, 61 °C and 70 °C at pressure levels of 6 kPa - 10 kPa (60 mBar - 100 mBar). Despite the difficulty of studying and establishing the role of the extractives in changes in wood color during vacuum drying, we found relationships between the drying temperature, antioxidant potential and C=O peak intensities in the infrared spectra. By the oxidation and hydrolysis reactions, certain chemical compounds are modified. In addition, the presence of water and air accelerates the formation of organic acids (acetic acid). These acids catalyze the hydrolysis of hemicelluloses. The increase in color saturation and brightness can be related to the thermal degradation of extractives (mainly the ellagitannins). Une analyse des mécanismes de discoloration du bois de chêne au cours d’un séchage sous vide sur plaques nous a permis de dégager les mécanismes principaux de l´altération de la couleur. Ces mécanismes sont la dégradation des hémicelluloses, l’oxydation des tannins et le dégagement de composants volatiles organiques. Nous avons étudié les altérations du matériau par la mesure de la couleur, le dosage du potentiel antioxydant et l’analyse des surfaces par spectroscopie infrarouge. Différentes conditions de séchage : 46 °C, 61 °C et 70 °C et niveaux de pression 6 kPa - 10 kPa (60 mBar - 100 mBar) ont été appliquées. Malgré la difficulté d’étudier et d’affirmer le rôle des extractibles dans la discoloration du chêne au cours du séchage, nous avons montré des relations entre la température appliquée, les valeurs des potentiels antioxydants et les intensités C=O des spectres FTIR. Par des phénomènes d’oxydation et d’hydrolyse, certains constituants chimiques sont modifiés. En outre, la présence d’eau et d’air accélère la formation d’acides organiques (acide acétique). Ces acides catalysent l’hydrolyse des hémicelluloses. L’augmentation de la saturation et de la luminosité peuvent être liées à la dégradation thermique des extractibles (éllagitanins principalement). Estudio de las alteraciones de color en madera de encino europeo durante el secado a vacío Un análisis de los mecanismos de decoloración de la madera de encino europeo durante un proceso de secado al vacío por contacto ha permitido identificar los principales mecanismos de la alteración del color. Estos mecanismos son la degradación de las hemicelulosas, la oxidación de taninos y la pérdida de compuestos orgánicos volátiles. Se estudiaron las alteraciones del material midiendo los cambios de color, determinando el potencial antioxidante y analizando la superficie del material por espectroscopía infrarroja. Las condiciones de secado aplicadas fueron las siguientes: 46 °C, 61 °C y 70 °C a niveles de presión de 6 kPa - 10 kPa (60 mBar - 100 mBar). A pesar de la dificultad de estudiar y establecer el papel de los extractivos en los cambios de color durante el secado a vacío, en este trabajo se muestra la relación entre la temperatura de secado, los valores de potencial antioxidante y las intensidades de los picos C=O de los espectros. Por medio de mecanismos de oxidación e hidrólisis, ciertos compuestos químicos son modificados. Por otro lado, la presencia de agua y aire aceleran la formación de ácidos orgánicos (ácido acético). Estos ácidos catalizan la hidrólisis de las hemicelulosas. Un aumento de la saturación del color y la luminosidad pueden estar relacionados con la degradación térmica de los extractivos (principalmente de los elagitaninos). Instituto de Ecología, A.C. 2016-09-19 info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion Artículo evaluado por pares application/pdf text/html https://myb.ojs.inecol.mx/index.php/myb/article/view/1329 10.21829/myb.2016.2221329 Madera y Bosques; Vol. 22 No. 2 (2016): Summer 2016; 119-130 Madera y Bosques; Vol. 22 Núm. 2 (2016): Verano; 119-130 2448-7597 1405-0471 fra https://myb.ojs.inecol.mx/index.php/myb/article/view/1329/1499 https://myb.ojs.inecol.mx/index.php/myb/article/view/1329/1579 Derechos de autor 2016 Madera y Bosques |
| spellingShingle | Sandoval Torres, Sadoth Jomaa, Wahbi Marc, Françoise Puiggali, Jean-Rodolphe Study of color alterations in European oak wood during vacuum drying |
| title | Study of color alterations in European oak wood during vacuum drying |
| title_full | Study of color alterations in European oak wood during vacuum drying |
| title_fullStr | Study of color alterations in European oak wood during vacuum drying |
| title_full_unstemmed | Study of color alterations in European oak wood during vacuum drying |
| title_short | Study of color alterations in European oak wood during vacuum drying |
| title_sort | study of color alterations in european oak wood during vacuum drying |
| url | https://myb.ojs.inecol.mx/index.php/myb/article/view/1329 |
| work_keys_str_mv | AT sandovaltorressadoth studyofcoloralterationsineuropeanoakwoodduringvacuumdrying AT jomaawahbi studyofcoloralterationsineuropeanoakwoodduringvacuumdrying AT marcfrancoise studyofcoloralterationsineuropeanoakwoodduringvacuumdrying AT puiggalijeanrodolphe studyofcoloralterationsineuropeanoakwoodduringvacuumdrying AT sandovaltorressadoth etudedesalterationsdelacouleurduboisdechenelorsdusechagesousvidediscontinu AT jomaawahbi etudedesalterationsdelacouleurduboisdechenelorsdusechagesousvidediscontinu AT marcfrancoise etudedesalterationsdelacouleurduboisdechenelorsdusechagesousvidediscontinu AT puiggalijeanrodolphe etudedesalterationsdelacouleurduboisdechenelorsdusechagesousvidediscontinu |
