Assessment of near infrared spectroscopy for energetic characterization of olive byproducts

• Energetic characterization of 250 olive byproducts has been performed.
• NIR spectroscopy models have been generated with good accuracy.
• External validations of the models have been carried out with excellent results.

The use of biofuels is a key factor in this transition away from fossil fuels. Today, biofuels are only a small share of world total energy supply. The characterization of biomass is a substantial improvement in the valorization of these resources, allowing a rational and controlled use of its energy potential. Therefore, a fast, reliable and cheap analytical technique is mandatory in order to increase the quality control of these products in the bioenergetic industry and enable comprehensive traceability of raw materials and processes in pursuit of a better use of resources. Near-Infrared (NIR) spectroscopy is eligible for the development of quality control systems of products and processes in accordance with the new demands taking into account their high response speed, low cost per sample, absence of sample preparation, versatility for the analysis of many different products and parameters. NIR spectroscopy prediction model for determination of quality parameters such us moisture, gross energetic value, ash content, volatile fraction content, and elemental composition (Carbon, Hydrogen, and Nitrogen) from ground and dried olive residues have been obtained. High accuracy in prediction for a test set has been achieved for all the parameters (R2 > 0.7) except for Hydrogen content. As expected, Standard Error of Prediction (SEP) for ground samples is better than dried samples except for moisture content. This study illustrates the possibility of using the NIR technique in combination with multivariate data analysis to predict economically important properties of olive byproducts for energetic uses.