Low-viscosity alginate-based hollow salt: A strategy for salty taste intensification and high-salt adverse effect reduction in vivo.

High salt consumption has been confirmed to be closely associated with various health risks such as hypertension, cardiovascular disease, and kidney injury. Hollow salt represents an effective salt reduction strategy to address these risks. This study developed a hollow-structured salt using low-viscosity alginate (LV-alginate), a seaweed-derived hydrocolloid. The salt particles had a size of 4.87 ± 2.68 μm. Sensory evaluation demonstrated that the hollow salt significantly enhanced saltiness perception, enabling a 36% reduction in sodium content while maintaining equivalent salt intensity. As confirmed by the experimental results, the saltiness enhancement was achieved by the increased specific surface area of the hollow structure, which accelerated the dissolution rate of sodium ions, and the adhesive property of LV-alginate, which prolonged the contact time between salt and the tongue surface. Furthermore, in vivo experiments in mice demonstrated that LV-alginate incorporation not only reduced sodium accumulation and alleviated kidney injury by promoting urinary sodium excretion, but also improved high-salt intake-induced gut microbiota dysbiosis. Specifically, LV-alginate incorporation significantly reversed the high-salt-induced increase in the Firmicutes/Bacteroidota ratio and increased the beneficial bacteria Lactobacillus and Akkermansia. In summary, this study developed and validated the potential of LV-alginate incorporation to prepare hollow salt as an effective salt-reduction strategy.