The influence mechanism of rice protein on leached amylose molecular structure: Steric hindrance effect of protein bodies
Published:19 November 2024
DOI: 10.1016/j.foodres.2024.115362
Jiali Hu, Ling Zhu, Yayuan Zhang
Abstract
The impact of protein content on rice cooking properties has been well-studied, but the role of protein morphology remains unclear. This study identified that protein in both raw and cooked rice exists in protein bodies, not in a matrix or network. Using fluorescence microscopy, these protein bodies were isolated, stained, and visualized in situ, showing no significant difference between raw and cooked rice. Varying concentrations of proteinase were used to study their effect on rice cooking properties. Mild proteinase (0.1?%-0.5?%) exposure revealed internal hydrophobic groups, limiting amylose leaching and reducing adhesiveness from ?507.944?N·s to ?851.920?N·s. Higher proteinase concentrations (1?%-5 %) loosened the rice structure, enhancing water absorption and starch gelatinization, resulting in decreased hardness and springiness but increased adhesiveness from ?176.008?N·s to ?129.550?N·s. The primary influence of protein bodies on cooking properties is steric hindrance, maintaining grain structure stability, affecting the coated layer’s thickness, and ensuring moisture retention within the rice kernel. This study underscores the importance of protein bodies in rice cooking properties and provides insights into protein morphological structure’s role in other cereals. Moreover, regulating the roles of protein bodies presents a potential strategy for modulating the texture of rice, thereby enhancing its cooking qualities.