DEVELOPMENT OF NIRS METHOD FOR ENERGETIC VALUE OF HIGH FIBER CANE CLONES

Sypecar is a project carried out by Cirad which aims at studying high fiber cane for energetic valorization. One component of this project deals with fast and easy assessment of raw material using a semi-automatic Near Infra-Red Spectroscopy (NIRS) device (CPS instrument from Bruker based on Matrix F) dedicated to fresh cane analysis. Wet chemistry characterization consists in shredding stalk cane sample, pressing the resulting pulp in a hydraulic press and collecting plug and juice obtained. Then plug is weighed for determination of fibre content (fibre% cane) while juice is filtered for determination of dry content (known as brix) and sugar content (known as pol). Those information were collected for high fiber cane and were completed by moisture content (MC) and Net Calorific Value (NCV). A calibration per component was developed. They were based on around 330 samples dataset from heterogeneous samples of the project Sypecar, including different varieties, two locations and varying ages. The predictions exhibited reliable results, since the coefficients of determination (R2) of regressions between predicted and observed values exceeded 0.9 for all traits and Ratio Performance to Deviation (RPD=Standard deviation/standard deviation of residuals) were higher than 4. The performances for the two constituents of interest were promising: The fiber calibration SEP was 1.22%, with a R2 equal to 0,96 and the NCV SEP was 147 kj/kg, NCV minimum and maximum values were respectively 188 and 5022 Kj/Kg, with a SD equal to 1209 Kj/Kg. (Resume d'auteur)