Rice embryo is more abundant than endosperms in nutrients such as proteins, lipids, and vitamin B1. In this study, we constructed p53 plasmid that could be expressed in a plant system, and investigated optimal germination conditions in a variety of media. For construction of p53 plasmid, we performed p53 amplification from pCDNA-p53, subcloned to TA cloning vector, and then reconstructed into pGEM-CaMV plant expression vector. On the other hand, we prepared a variety of imbibition buffers and complete media for efficient germination of the rice embryo. Imbibition buffers prepared with different concentrations of salt or detergent showed no significant effect on germination efficiency. We prepared further culture media, such as solid agar, liquid media, and paper towel to establish the optimal conditions. Rice embryo showed germination rates of more than 70% in the solid medium, more than 60% in the paper towel medium, but less than 25% in liquid media, although germination rate did not differ with varying concentrations of salt and sucrose in culture media. Under the optimal germination conditions, we introduced the p53 plasmid using imbibition method, and finally detected human p53 gene expression in the germinated rice embryo. This method might present a novel, practical approach for evaluating efficient gene expression utilizing imbibition method in rice embryo.

Brown rice (Oryza sativa) is rich in nutrients, including dietary fiber, vitamins, minerals, and other unmeasured constituents, as well as carbohydrates. Brown rice is an applicable staple for chronic diseases, such as diabetes and hyperlipidemia, but it is not commonly used in dietary management due to several reasons. In this study, we investigated the possibility of using digestive enzymes to process brown rice. When the weight of the brown rice was measured after packing in the same volume of water, it was increased in pectinase-treated brown rice compared to control or collagenase-treated brown rice. Using SEM analysis, we observed huge scratches and nanopores on the surface of the brown rice after the pectinase treatment, but the nutritional components were preserved. We also analyzed the water adsorption rate and performed a starch reaction assay to examine the physical changes after the pectinase treatment. The pectinase-treated brown rice showed a higher water adsorption rate and a faster starch reaction than the nontreated brown rice. These results suggest that digestive enzymes like pectinase can aid the nutritional preservation of brown rice and improve its taste.