Effect of Wheat Starch Hydration on Noodle Quality under Different Storage Periods

To investigate how the hydration ability of wheat starch that under different storage period (0, 1, 2, 3 years) affected the quality attributes of noodles. Wheat grains with varying storage years were firstly selected for this research, then the starch hydration ability was evaluated by technical methods such as room temperature testing or water contact angle measurements. Furthermore, the microscopic structure and rheological properties of reconstituted dough, and quality attributes of noodles produced by this dough were investigated, which could provide the theoretical basis for the rational application of wheat stored under different periods. Results showed that as the extension of wheat storage time, both the water absorption capacity and solubility of wheat starch respectively increased to 2.47 g/g and 6.51%, while the swelling power and water contact angle decreased to 5.59 g/g and 59.97°, respectively. Moreover, the continuity of the gluten network structure in reconstituted dough deteriorated with increased storage time, which induced the decrease of the storage modulus (G′) and the loss modulus (G″) of the reconstituted dough. This might be due to the long-term storage disrupted the molecular and aggregated structures of wheat starch, which led to disordered starch hierarchical structure, thus resulting in the competitive water absorption between starch and gluten proteins, aggregation of starch molecules and less stability of gluten network structure. In comparison with reconstituted noodles made from freshly harvested wheat starch, those prepared by stored starch fractions presented strengthened hardness and chewiness (P<0.05), especially for RF-3 sample, its hardness and chewiness increased from 4451.97 g to 7537.71 g and 1423.64 g to 3851.87 g, respectively. The increase in cooking loss rate and the decrease in sensory score of noodles were consistent with this result. In conclusion, the increased hydration capacity of wheat starch with longer storage time leads to alterations in its interaction with gluten proteins, thereby leads to the deterioration of the processing and cooking qualities of wheat-based products.