Measuring Medullation in Mohair with near Infrared Reflectance Analysis

Existing methods of measuring medullation in wool and mohair have certain shortcomings, such as testing time, cost, and variability, especially at low levels of medullation. A new method using near-infrared analysis (NIRA) is proposed. The main difference between the new method and the conventional NIRA method involves the immersion of the mohair sample in a liquid with a refractive index similar to that of mohair. All the calibration and validation statistical parameters improve significantly compared to the conventional NIRA method. The standard error of prediction for the new method is 0.31%. There is a high reproducibility of single measurements, especially at low levels of medullation. The main factor limiting the precision of conventional NIRA estimates of medullation is considered to be the influence of the light signal reflected from fiber surface.