Effect of dew retting of different harvesting periods on the hemp fibers quality

Abstract : This work assesses the impact of dew-retting duration (up to 9 weeks) on hemp fibers properties (color, chemical composition, mechanical performance, volatile organic compounds (VOCs) emissions). Different harvesting periods were compared (beginning and end of flowering and seed periods). Results show a change of color, an evolution in chemical composition with a decrease in the pectins and hemicellulose contents, an increase in cellulose contents, different behaviors in mechanical properties and evolution in VOCs nature and amounts. The retting duration differs as more than 9 weeks are required for fibers sampled during flowering while only 3 weeks are needed for fibers in seed period.