Group for Cereals and Oils Processing, College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
Glyn O. Phillips Hydrocolloid Research Centre at HBUT, School of Food and Biological Engineering, Hubei University of Technology, Wuhan 430068, China.
Int J Biol Macromol. 2022 May 31;208:80-87. doi: 10.1016/j.ijbiomac.2022.03.034. Epub 2022 Mar 10.
Cold-chain cooked rice is an instant food consumed worldwide. Through inspecting rice structural alterations during digestion, this work discloses how microwave reheating tailors the starch digestibility of cooked rice following cold storage. The cold storage allowed approximately 2% of B-type (not V-type) starch crystallites, more nanoscale and short-range orders, and smaller pores in the rice matrix. These changes retarded the hydrolysis of structural domains (e.g., amorphous regions and short-range orders) during digestion, which increased the content of slowly digestible starch to about 38.16%. Then, microwave reheating partially disrupted the B-type crystallites and nanoscale orders, but unaffected the contents of V-type crystallites and short-range orders. Even with such structural disruptions, the resistant starch content was apparently increased to approximately 30.06%, as the structural domains became less susceptible to the digestion. Additionally, for the rice samples, the percentage of V-type crystallites could be largely increased from ca. 3% to 13%-14% during digestion.
冷链熟米饭是一种全球范围内食用的即食食品。通过检测大米在消化过程中的结构变化，本研究揭示了微波加热如何在冷藏后调整熟米饭的淀粉消化率。冷藏使大约 2%的 B 型（而非 V 型）淀粉晶型、更多的纳米级和短程有序以及大米基质中的小孔出现。这些变化在消化过程中减缓了结构域（如无定形区域和短程有序）的水解，使慢消化淀粉的含量增加到约 38.16%。然后，微波加热部分破坏了 B 型晶型和纳米级有序，但对 V 型晶型和短程有序的含量没有影响。即使存在这种结构破坏，由于结构域对消化的抵抗力增强，抗性淀粉含量也明显增加到约 30.06%。此外，对于米饭样品，在消化过程中，V 型晶型的比例可以从约 3%大幅增加到 13%-14%。
