Abstract: Germination is a key biological process to improve the nutritional quality and functional properties of grains. In recent years, with their advantages of environmental friendliness and pollution-free nature, physical technologies such as magnetic field, electric field, microwave, and irradiation (ultraviolet, infrared/near-infrared) have been gradually applied to improve the quality and efficiency of grain germination. Magnetic field, electric field, and microwave exert their effects mainly through non-thermal mechanisms, while irradiation exerts both thermal and non-thermal effects. In this article, we systematically review the application effects and mechanisms of the four types of physical techniques in promoting grain germination. The results show that physical treatment with appropriate parameters can significantly improve the germination rate of grains, accelerate the germination process, and promote radicle elongation and biomass accumulation. By activating amylase, protease and key enzymes involved in the phenylpropanoid metabolic pathways, it can enrich bioactive components such as γ-aminobutyric acid, phenols, and flavonoids. It can also enhance the activity of antioxidant enzymes, reduce the content of malondialdehyde, and alleviate oxidative damage caused by lipid peroxidation. Its core mechanism involves the regulation of cell membrane structure and function, the activation of ion channels and signal transduction pathways, and the upregulation of the expression of germination and metabolism-related genes. Although physical technologies have broad prospects in the enrichment and processing of active substances in grain sprouts, they still face challenges in parameter standardization, in-depth analysis of the mechanism of action and large-scale application. This paper aims to provide theoretical support for the development of green and efficient grain processing technologies.

Key words: physical treatment; grain germination; antioxidant system; molecular mechanism; synergistic regulation