Effect of phosphate salts on the shelf-life and quality characteristics of semi-dried noodles

The effect of four types of phosphate salts (PS) on the shelf-life and quality characteristics of semi-dried noodles, as well as their underlying mechanism were investigated. Microbial analysis showed 0.2% or 0.4% sodium dihydrogen phosphate (MSP) extended the shelf-life of noodles from 3 days to 5 days. Nuclear magnetic resonance analysis revealed PS decreased the mobility of free water in noodles. Cooking and texture analysis showed sodium pyrophosphate (TSPP) increased the cooking loss of noodles, and MSP decreased the tensile force of noodles. Sodium hexametaphosphate (SHMP), TSPP, and MSP increased the hardness of noodles, while sodium tripolyphosphate (STPP) decreased the hardness. Thermal properties analysis indicated STPP and TSPP increased the gelatinization enthalpy (ΔH) of starch in noodles, while SHMP and MSP decreased the ΔH. Furthermore, confocal laser scanning microscopy and scanning electron microscopy showed SHMP, STPP, and MSP strengthened the gluten network formation, while TSPP weakened the network.