Abacá (Musa textilis) grades and their properties—A study of reproducible fibre characterization and a critical evaluation of existing grading systems

The primary objective of the study was the investigation of the tensile properties of abacá (Musa textilis) fibre bundles and how the fibre bundle quality depends on the grading. For this purpose all market relevant abacá grades were determined regarding to tensile properties, fibre bundle width, and colour by budget priced methods that guarantee an excellent reproducibility.It was found that the classical grading by visual inspection is only applicable for hand-stripped fibre bundles. In approximation, the fibre bundle width increased from the excellent grades to the residual grades while the tensile strength decreased. This was not true for spindle-stripped fibre bundles that had almost equal tensile strengths over the whole grading range. It was found that the knife serration number (a main dissimilarity of the two extraction methods) influenced the abacá quality significantly.Moreover, the CIELab-value a* (redness indicator) of the fibre bundles depends on their position in the pseudostem. We hypothesized that the position dependent colour change is based on a gradual change in lignification. It could be shown that an automated qualification of the colour (CIELab-system) and the fibre bundle width (Fibreshape-system) could be a great benefit for the abacá grading.

► The serration number had a great impact on the abacá fibre bundle quality. ► Fibre bundles from the inner position of the pseudostem were less lignified. ► Manual grading caused in dissimilar qualities within one grade. ► Automated qualification systems were beneficial in terms of reproducibility.