Pectin Dissolution Kinetics in Bast Fibre Wet Spinning Troughs
Trough temperature at 68°C accelerates pectin dissolution, lowering drafting force to stabilize wet-spun linen yarn counts up to Nm 60.
Galacturonan
Pectous Polysaccharide
Acidic polymers constitute the main structural components of the pectin matrix that binds flax fibers together in the stem of the plant. The amount of galacturonan present in the fiber bundles dictates the stiffness of the unretted flax. Retting operators monitor the breakdown of this carbohydrate in the Retting Chemistry Report.
Removing this substance is necessary to allow the separation of individual textile fibers.
Enzymatic Breakdown
Biochemical treatments target the esterified linkages within pectin to loosen the fibers from the woody core of the flax stem. During this process, galacturonan is converted into shorter soluble chains that wash out of the flax straw. This extraction is monitored by testing the wastewater for dissolved sugars.
Technicians log these sugar concentrations in the Retting Chamber Quality Log to determine when the rinse cycle should commence. Over-retting must be avoided because once the pectin is consumed, the bacteria begin to attack the cellulose, which weakens the fibers.
Yarn Softness
Residual gums left on the fiber bundle cause stiffness in the spun yarn and reduce the efficiency of the drafting rollers. If galacturonan remains in high concentrations, the spun linen will feel rough to the touch and resist bleaching chemicals. Effective scouring removes the remaining polymer to ensure a smooth and pliable textile finish.