Chickpea protein isolate-pullulan polysaccharide hydrogel enhances gel performance and saltiness perception in low-salt shrimp surimi gels via controlled sodium release and structural optimization

This study investigates the novel application of a chickpea protein isolate (CPI)- pullulan polysaccharide (PUL) hydrogel to enhance the gel properties and saltiness perception of reduced-salt (1.5 %) shrimp surimi gels, with conventional salt addition (3 %) serving as a benchmark. The incorporation of 15 % CPI-PUL hydrogel significantly improved the functionality of reduced-salt gels: Water holding capacity increased by 38 %, hardness increased by 1.49 times, and microstructural analysis revealed a markedly denser and more stable gel network compared to reduced-salt controls without hydrogels. Crucially, electronic tongue analysis and inductively coupled plasma optical emission spectrometer confirmed that the CPI-PUL hydrogel effectively enhanced the perceived saltiness of reduced-salt gels. Elemental mapping indicated a heterogeneous Na + distribution within the gel matrix. By employing in vitro oral mastication and digestion simulations, the mechanism underlying saltiness enhancement was elucidated. Analysis of digestive fluid conductivity demonstrated rapid Na + release into simulated saliva within the first 30 s of mastication. Notably, during the subsequent chewing phase (30–60 s), the CPI-PUL hydrogel modulated Na + release kinetics, delaying its liberation and thereby prolonging the duration of salty taste perception. This targeted temporal control of sodium release presents an innovative strategy for effective salt reduction in surimi-based products without compromising sensory quality.