Effects of Konjac Glucomannan on the Physicochemical and Structural Properties of Neghal Date Paste

Neghal, a dry Emirati date variety, is recognised for its nutritional richness and high dietary fibre content. However, its low moisture and dense, fibrous texture present challenges in processing and texture modification. This study investigates the effect of konjac glucomannan (KG), a natural hydrocolloid and soluble fibre, on the physicochemical and structural properties of Neghal date paste. KG was incorporated at concentrations of 0%, 1%, 3%, and 5% (w/w), and the resulting pastes were analysed for texture, water activity, thermal behaviour, microstructure, and rheological properties. The addition of KG significantly reduced water activity and water loss, contributing to improved shelf life, microbial safety, and product stability. Textural analysis showed moderate increases in hardness, gumminess, and chewiness, indicating a firmer and more cohesive paste. Thermal analysis revealed a decrease in endothermic transition temperatures, suggesting easier processing and reduced energy requirements. Microstructural observations showed that Neghal’s fibrous matrix resisted uniform gel formation, resulting in less cohesive and more heterogeneous textures. Rheological tests confirmed an increase in elastic modulus, reflecting enhanced structural integrity and viscoelastic behaviour. Due to its fibrous nature, Neghal may also offer health benefits related to digestive wellness and glycemic control. These findings support the use of KG to improve the functionality of Neghal paste in plant-based, reduced-sugar, and clean-label food applications.