A Preliminary Evaluation of near Infrared Spectroscopy for Assessing Physical and Chemical Characteristics of Flax Fibre

Abstract

Near infrared (NIR) spectroscopy has been used extensively as a rapid tool for the evaluation of protein, fibre fractions and other parameters of feeds and forages. The relative proportions of organic components present in flax fibre will vary depending on variety, growing and retting (controlled rotting) conditions, mechanical and processing factors. The presence of the main fibre fractions, such as cellulose, hemicellulose, lignin, wax and others will determine the physical and chemical characteristics. Tests for fibre distribution, fineness and strength are currently assessed using tedious and long-winded methods. The aim of this investigation was to evaluate the use of NIR spectroscopy for developing calibrations for predicting important fibre parameters. In order to develop a model, a range of samples representing poor, medium and good quality fibres are included in the calibration and validation sample sets. Derivative thermogravimetric analysis (DTG) and airflow methods have shown that differences in fibre fineness can be modelled from NIR spectral data in the ranges 1800–2498nm and 1100–2498nm, respectively. Fibre strength measurements were correlated with the NIR 1800–2498nm spectral band. The determination of fibre components using acid and neutral detergent methods exhibited a poor correlation with NIR spectroscopy assessments on the same sample set. NIR spectroscopy has proved to be a useful tool for predicting fibre fineness and strength in flax, however, its success will be dependent on the accuracy of reference measurements currently employed for fibre testing.