In this study, the effects of heating temperature on particle size distribution, microscopic morphology, hydration properties, and gel texture of fresh and aged rice flour particles with the same particle size as cultivar Wuyujing 3 were investigated to reveal the effects of disaggregation changes of starch granules after aging on rice gel texture and enhance the understanding of deterioration mechanism of rice eating quality caused by aging. Results showed that the small particle size peak volume fraction significantly decreased after aging, and aging made the reduction of peak volume fraction of small particle size faster. The light microscopy was consistent with the particle size analysis results. Scanning electron microscope showed that only the starch granules on the surface of rice flour particles could disaggregate at higher temperatures and after aging, while the starch granules inside were still aggregated together. Meanwhile, with the increase in heating temperature, the hardness and cohesiveness of rice gel of fresh rice and aged rice increased significantly, which may be caused by the skeletal role of the remaining larger particles. The higher hardness and lower cohesiveness of aged rice gel suggest that the resistance of the remaining larger particles to external forces decreased at the second compression. The results of particle size analysis well supported the change of rice gel texture. These results suggested that the difficulty of disaggregation between starch granules was the underlying reason for the change of gel texture after rice aging, which could be helpful to deepen the understanding of the rice aging mechanism and provide an experimental basis for improving rice eating quality.
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