Tailored Eating Quality and Starch Structural Features of Frozen Wet Rice Noodle: Influence of Retrogradation Time, Freezing Temperature, and Rice-Water Ratio.

The production of quick-frozen wet rice noodles involves wet-milling, steaming, shaping, retrogradation, and freezing. This study investigated the changes in the quality and starch structural characteristics of frozen rice noodles (RN) prepared at different retrogradation times, freezing temperatures, and rice-water ratios. It was revealed that extending the retrogradation time would help to enhance the toughness of the product, increasing the rice-water ratio would reduce the hardness of the RN, and too low a freezing temperature would cause higher cooking losses. The RNs frozen at -32°C (6 h retrogradation, 1:1.5 rice-water ratio) exhibited higher chewiness, lower cooking loss (1.31%), and more uniform water distribution. Decrease in freezing temperature (-20 to -80°C) reduced the freezable water in RN (from 708.8 to 543.9 J/g), while retrogradation time and rice-water ratio showed no single change trend. All frozen RNs contained B + V-type microcrystals, and the crystallinity increased (from 3.02 to 4.16%) with the increase of rice-water ratio (from 1:1 to 1:2). But their short-range order structure was almost unchanged. Prolonging the retrogradation time enriched the aperiodic nanostructures, whereas decreasing the freezing temperature presented opposite effects. Too long a retrogradation time or an inappropriate freezing temperature (too high or too low) would produce unfavorable network structures in RNs. The correlation between the individual properties is not uniform in different conditions. The findings of this research provide essential data support for the formulation and manufacturing of quick-frozen wet rice noodles with desirable quality.