Abstract: In order to systematically investigate the quality differences between salted and alkaline noodles and the underlying mechanism, the effect of NaCl and K2CO3 on the quality formation of noodles was studied by evaluating the farinograph and extensograph properties and viscosity properties of wheat flour, as well as the cooking properties, texture properties, and storage stability of noodles. Additionally, the microstructure, protein aggregation and volatile components were investigated to explore the underlying mechanisms of the quality differences. The results showed that salt improved the extensibility of dough and noodles, endowed noodles with higher smoothness and elasticity, and showed little effect on starch viscosity, while alkali enhanced the tensile resistance of dough and the hardness and breaking force of cooked noodles, and increased the gelatinization viscosity of starch. The cooking loss of noodles increased with the addition of salt and alkali. Both salt and alkali significantly inhibited the increase of total plate count (TPC) in fresh noodles and consequently enhanced the storage stability, but 0.5% K2CO3 accelerated the browning rate. The scanning electron microscopy (SEM) results showed that NaCl induced a smooth surface microstructure, while K2CO3 resulted in a rough surface of noodles; K2CO3 significantly increased the rate and extent of thermal polymerization of proteins in noodles. NaCl increased the type and concentration of volatile components in noodles, thereby making the aroma of noodles more intense, but the flavor was similar to that of the control. K2CO3 significantly changed the flavor of noodles and resulted in the generation of unique aldehyde compounds.

Key words: salted and alkaline noodles; macroquality; microcharacteristics; flavor; gluten