Hydrothermal extraction and characterization of hemicellulose from biomass as a natural emulsifier

Hemicelluloses have emerged as a promising alternative to traditional natural emulsifiers; however, its application is constrained by molecular heterogeneity and limited emulsifying performance. This study developed a hydrothermal-based process to extract and tailor hemicelluloses from biomass with enhanced emulsifying functionality. Switchgrass was hydrothermally treated to release hemicelluloses, which was subsequently fractionated into three molecular-weight ranges via graded ethanol precipitation. Chemical and structural analyses revealed that the hydrothermal treatment effectively disrupted the plant fiber matrix, facilitating hemicelluloses release while preserving its amphiphilic character, attributed to minor lignin grafting. Notably, high-molecular-weight hemicelluloses exhibited superior emulsifying capacity compared to low-molecular-weight hemicelluloses. The optimized hemicelluloses achieved a high emulsifying activity index of 100.4 m²/g and outstanding emulsifying stability, maintaining uniformly distributed oil droplets below 4 μm after 21 days-comparable to commercial gum arabic. This study presents a novel approach to produce high-performance hemicelluloses-based emulsifiers from biomass, supporting the advancement of sustainable food ingredients.