Impact of Hot Water Extraction on the Chemical Composition of Hemp (Cannabis sativa L.)

TL;DR

This study examines how hot water extraction affects the chemical makeup of hemp stalks, showing significant changes in extractives, lignin, and cellulose.

Contribution

The study provides new insights into the selective modification of lignin and hemicellulose through successive hot water extraction cycles in hemp.

Findings

Extractives and ash were effectively removed, decreasing from 3.2 to 2.0% and from 3.9% to 2.7%, respectively.

Xylose content in the liquid phase increased significantly after V cycles, indicating hemicellulose reduction.

Cellulose content in the solid material increased from 42.9% to 46.2% after XV cycles.

Abstract

An investigation of the effect of intense Hot Water Extraction (HWE) on the chemical properties and processability of shredded hemp stalks (Cannabis sativa L.) is presented in this study. The chemical composition of untreated hemp was compared to that of hemp subjected to V and XV successive HWE cycles. This study investigated changes in selected chemical compounds, such as extractives, lignin, cellulose, ash, and monosaccharides such as glucose and xylose. Additionally, post-HWE liquids were analyzed. Lignin content was determined by the UV–VIS spectrophotometry method, whereas monosaccharides (glucose, xylose) and inhibitors (formic acid, acetic acid, levulinic acid, ethanol, 5-(hydroxymethyl)furfural, and furfural) were identified by HPLC. Extractives and ash were effectively removed by the HWE process, decreasing from 3.2 to 2.0% and from 3.9% to 2.7%, respectively. The reduction in acid-soluble lignin was an important finding, indicating a selective modification of the lignin matrix. By the end of V cycles, xylose content in the liquid phase significantly increased from 117.9% to 19.4%, indicating a reduction in hemicelluloses. The cellulose content of the solid material rose from 42.9% to 46.2% at the end of XV cycles.

Figures