abstract
This paper reports the extraction of Eucalyptus globulus bark and a concentration strategy to obtain a phenolic-rich extract for application in the leather tanning industry. The profiles of total phenolic compounds (TPC) and tannins contents in water and dilute alkali as a function of extraction temperature and time led to the selection of the best conditions concerning extraction yield and selectivity. The selectivity profile for TPC and tannins was established, and a maximum of 20 g per kg of bark was found, representing 2.5 g per L of extract produced. On the basis of these results, the conditions selected to produce the extract for the application envisaged in this work were: water, 140 degrees C and 120 min. To increase the extract concentration, recirculation of the extracts over fresh bark (similar to a continuous bark extraction process) was performed and evaluated. The increment in phenolic compounds was about 4, attaining the final concentration of 8.6 g/L for TPC and 6.5 g/L for tannins. The final extracts showed leather retanning aptitude equivalent to a commercial extract of chestnut and revealed good performance in the production of leather articles like box-calf and nubuck.
keywords
E-RUDIS; POLYPHENOLIC COMPOSITION; MASS-SPECTROMETRY; CAMALDULENSIS; CHROMATOGRAPHY; CHEMISTRY; WOOD
subject category
Chemistry; Science & Technology - Other Topics; Engineering
authors
Pinto, PCR; Sousa, G; Crispim, F; Silvestre, AJD; Neto, CP
our authors
Armando Jorge Domingues Silvestre
Full professor
Carlos Pascoal Neto
Raiz DirectorProjects
Eucaleather- Aplication of Liquid Extracts of Eucalyptus globulus in Leather tanning (EUCALEATHER)
acknowledgements
This work was carried out under Project EUCALEATHER (program i-centro/CCDRC, Portugal). Associate Lab CICECO (Pest-C/CTM/LA0011/2011) and Associate Lab LSRE/LCM (Pest-C/EQB/LA0020/2011) are acknowledged for funding.