Determining residual gum content of bast fibres

The measurement of fibre quality in bast fibres is related to the amount of gum (lignin, hemicellulose, wax and pectin) left in the fibre after the retting process. Large amounts of gums present represent poor separation of fibre. Efficiency of retting can be monitored by measuring the residual gum content of the retted fibre.

This paper investigated the use of ultrasonic vibration combined with chemical retting as a pre-treatment to improve accuracy of traditional residual gum content test. Work was conducted on chemically retted hemp fibre. Pre-treatment conditions were analysed by determining the best chemical combination, chemical concentration and treatment time. Fibres were examined for successful separation using optical microscopy and optical fibre diameter analysis (OFDA). The work proposed a new method for determining the residual gum content of hemp fibre.