Multivariate analysis of coconut residues by near infrared spectroscopy

Published Date
1 June 2015, Vol.138:263–272, doi:10.1016/j.talanta.2015.03.014

Author  

M.K.D. Rambo ^a,b

A.R. Alves ^c

W.T. Garcia ^c

M.M.C. Ferreira ^a,,

aInstitute of Chemistry, University of Campinas – UNICAMP, CEP 13083-970 Campinas, Brazil

bDepartment of Chemistry, University of Tocantins – UFT, CEP 77838-824 Araguaína, Brazil

cSugarcane Research Center – CTC, CEP 13418-900 Piracicaba, Brazil

Received 2 December 2014. Revised 6 March 2015. Accepted 7 March 2015. Available online 12 March 2015. 

Highlights

• Characterization of coconut residues.
• •
  Physicochemical analysis of several processing stages.
• •
  Potential use of NIRS and chemometrics for determining biomass composition.
• •
  Biorefineries opportunities.

Abstract 

Near infrared (NIR) spectroscopy was used to determine the content of Klason lignin, acid-soluble lignin, total lignin, extractives, ash, acid-insoluble residue, glucose, xylose, rhamnose, galactose, arabinose, mannose and total sugars in coconut residues. The samples were analyzed at several processing stages: wet unground (WU), dried unground (DU) and dried and sieved (DS). Partial least squares models were built, and the models for the analytes exhibited R²>0.80, with the exceptions of rhamnose, arabinose, galactose, mannose and ash from all fractions, and the lignin content from the WU fraction, which were predicted poorly (R²<0.70). There were some significant differences between the models for the main lignocellulosic components at the various stages of biomass. These results proved that NIR spectroscopy is useful for analysis at biorefineries, and it can be used as a faster and more economical alternative to the standard methods.

Graphical abstract

Near Infrared Spectra for coconut samples and plot of reference versus predicted values from the calibration and external validation models for the total sugars.

Keywords

• Biomass residue
• Chemical composition
• Chemometrics
• Figures of merit
• Monosaccharide

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• ⁎ 
  Corresponding author.

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