Abstract: In this study, mung bean was subjected to instant high-temperature fluidization treatment at 160, 180, or 200 ℃. The effects on the starch digestibility of mung bean were investigated by analyzing alterations in microstructure, protein, and starch properties before and after the treatment. The results showed that the starch granules remained intact after the treatment. Flocs appeared on the starch surface and their volume rose as the temperature increased. The protein network in mung bean gradually contracted, causing starch granules to aggregate into clusters and forming a compact protein barrier layer encapsulating the starch aggregates. High-temperature fluidization had no significant effect on the secondary structure of proteins (P < 0.05), while the disulfide bond content initially decreased and then increased with increasing temperature. The total starch content and crystal type (A-type) of mung bean remained unchanged after the treatment. However, the amylose content increased from 30.09% to 40.17%, the crystallinity decreased from 22.38% to 15.86%, and the short-range order of starch significantly reduced. Meanwhile, the gelatinization temperature, gelatinization enthalpy, and pasting parameters decreased significantly, indicating markedly improved cooking properties. The resistant starch content increased by 13.52%, and the estimated glycemic index decreased from 51.75 to 44.54. In conclusion, high-temperature fluidization is a mild processing method that can generate a protein barrier layer around starch to slow down starch digestion and significantly increase amylose content, thereby achieving effective regulation of starch digestibility. This study provides technical support for the development of functional foods based on mung bean.

Key words: mung bean; high-temperature fluidization; protein barrier around starch; starch structure; starch digestibility