Corn is a globally grown crop and can be utilized in various ways, including as a resource of animal feed, human food, and chemicals. The endosperm is an important part of the corn kernel and is usually divided into vitreous endosperm and floury endosperm. Differences in the distribution of starch and protein determine the appearance and texture of these two endosperms (Gayral et al., 2016). The vitreous endosperm is yellow and semi-transparent, full of protein between the starch grains, and dense in structure, while the floury endosperm is white and opaque, low in protein content, not tightly bound to the starch grains, and loose in structure. The ratio of the floury and vitreous parts in corn kernels is used to categorize them into popcorn, flint, dent, and floury corn (Xu et al., 2019).

The primary biopolymers, specifically starch and protein, are found in many flour (starch)–based foods consumed around the world, and they supply the body with the energy and nutrients it requires (Zhang et al., 2021). Proteins and how they interact with starches contribute significantly to the structure and properties of these foods (Zhang, Zhang, & Zhao, 2023). Proteins in numerous starchy food matrices are capable of encapsulating or adsorbing the starch phase at the microscale, thereby interacting with the starch chains through non-covalent (hydrogen bonding, hydrophobic bonding, and electrostatic interactions) and covalent bonds (via the Maillard reaction) (Wang et al., 2021). Together with the hydration and gelation properties of proteins, these can all modulate the morphology, structure, pasting, rheology, and texture properties of starch.

Thermal treatment helped to promote starch–protein interactions and further modulate the structure and functionalities of starch. Rice starch–soy protein isolate interplay increased the pasting viscosity, reduced the paste stability of starch granules, and restricted the formation of short–range helices and long–range crystallites of starch molecules during heating (Wang et al., 2021). Dry heating treatment facilitated the interaction of rice starch and whey protein isolate, resulting in damage to both the long– and short–range orders and increasing the thermal stability of starch (Zhu et al., 2020). The addition of albumin and globulin reduced the peak storage and loss modulus of starch during the heating process (Ghumman, Kaur, & Singh, 2016).

Among various thermal methods, radio frequency (RF) treatment is a technique based on dielectric heating that penetrates foods to generate internal heat (Zhou, Yang, Tian, Kang, & Wang, 2023). Moreover, several studies have reported that RF heating modified the structural and physicochemical characteristics of starch (Ma et al., 2023; Zhang, Zhang, Zhang, Wang, & Zhao, 2022; Zhang, Zhang, Zhu, & Zhao, 2022). The RF could also change the structure of protein, promoting the aggregation and unfolding of the protein (Lian, Sun, Cheng, & Ma, 2022). Some hydrogen bonds in rice bran protein isolates were destroyed by RF treatment, which transformed ordered structures into disordered structures (Ling, Ouyang, & Wang, 2019). The conformations of starch and protein (protein aggregation, denaturation, and unfolding) can be influenced by thermal treatments and thus affect the interactions between them (Zhang et al., 2021). However, the changes in structure and functional characteristics of corn starch molecules in the presence of endogenous proteins under RF treatment have not been fully elucidated.

Emerging technologies that influence the interactions between starch and protein may pave the way for improving starch–based food in terms of health and nutrition aspects. Hot air (HA) assisted RF drying (HA-RF), a fast and efficient heating technique, has been widely applied to various food grains. In this study, the endosperms were separated from dent and flint corn kernels. Our objective was to investigate the effect of protein from endosperm and the interaction with starch on the micro-morphology, crystalline and short–range ordered structures, gelatinization, and rheology properties of corn starch–based matrices under different HA-RF treatments (50 °C, 60 °C, and 70 °C). Radio frequency applications in the food industry will grow as a result of this work to the body of knowledge on HA-RF treated protein and starch. Meanwhile, research on the effects of endogenous proteins on starch–based food systems can offer theoretical direction for the creation of better corn starch products that serve desired nutritional purposes.