Effects of rolling on eating quality, starch structure, and water distribution in cooked indica rice dough.

Background: Given the composition of rice and its lack of gluten proteins, rice flour fails to form a cohesive and elastic dough when mixed directly with water. Consequently, many rice products rely on rice sheets (RS) made by rolling cooked rice dough. Limited research exists on how the rolling process impacts the properties and structure of cooked indica rice dough.

Results: This study investigated the effect of the number of rolling passes on the eating quality, starch structure, and water distribution of cooked fermented indica RS formed by dough. When the number of rolling passes reached six, the RS (RP-6) that was obtained exhibited the lowest cooking loss, the highest hardness, adhesiveness, and chewiness, and optimal stretchability. It also demonstrated the lowest water loss after freezing. Dense microstructures were observed on both the surface and cross-section of RP-6. More ordered starch crystal structures and double helix structures were formed. The relative peak area of tightly bound water significantly increased in RP-6, indicating a stronger bonding status between the starch and water molecules. However, excessive rolling passes (more than six) led to a partial disruption of the internal RS structure, resulting in a decline in eating quality.

Conclusion: The study demonstrated the importance of the rolling process in improving the performance of RS. It was found that a moderate number of rolling passes was conducive to producing excellent RS, providing a theoretical basis for the production of high-quality rice-based products such as rice noodles, dumplings, and cakes. © 2024 Society of Chemical Industry.