In my laboratory, we are advancing research to elucidate the mechanism of action of functional ingredients in foods by focusing on the molecular interactions between food molecules and human molecules to clarify the mechanism of action of functional components in food, targeting the positive functions (antibacterial, antiviral, anticancer, antioxidant, antiglycation) and negative functions (carcinogenesis, allergenicity) of food. An important step in such research is to utilize recombinant proteins to clarify the function and structure of target proteins. In this talk, I will show examples of the use of artificial genes, which are useful tools for the expression of recombinant proteins, as well as examples of future applications.