| Summary: | 碩士 === 國立臺灣大學 === 農藝學研究所 === 105 === Nitrogen fertilizer application acts as a key factor to affect the rice (Oryza sativa L.) grain qualities and production yield. As the applied amount of nitrogen fertilizer increased, the production yield and protein content in rice grain raised. Most studies of nitrogen fertilizer application focus on nutrient components and tasting qualities of rice. However, fewer researches discussed the nitrogen fertilizer applied effects on functional components in rice grain. In this study, we used colored rice as major material. Colored rice is one kind of functional food and gets popular in late decades. It has abundant functional components and great antioxidant capacities. Those properties indicate its extraordinary value to improve health. Similarly, germinated brown rice is another kind of functional food that make people healthier. Brown rice with germinated treatment has elevated functional components level and enhanced antioxidant capacities. Especially, the γ-aminobutyric acid (GABA) content grows enormously in the sprouted rice. Previous studies presented that taking germinated rice as food lessened blood glucose and cholesterol. Also, the plentiful GABA content constitute tranquilizer, sleep aid and ease of presenile period disorders. The objective of this study is to investigate the effects of nitrogen fertilizer application and germinated treatment on the colored rice qualities and antioxidant capacities. Subsequently, the results can assist to build up good agricultural practice (GAP) model. In this study, we focused on local varieties of colored rice and conducted potted trial with low, medium and high applied amount (70, 140 and 210 kg ha -1 ) of nitrogen fertilizer. Four local varieties are Hualien black rice (HLB), Xingpu black rice (XPB), Xingpu red rice (XPR) and Taoyuan no. 3 (TY3) white rice. Part of the harvested rice were dealt with germinated treatment. The results revealed nitrogen fertilizer application did not affect the contents of protein and functional omponents such as anthocyanin, carotenoids, flavonoids and phenolic. Only under high applied amount of nitrogen fertilizer, there was significant reduction of production yield and some functional components. The contents of functional components mainly depend on varieties. Comparing total phenolic content and antioxidant capacities among varieties, the orders from highest to the lowest are red rice > black rice > white rice. The black rice has highest anthocyanin and carotenoids content. The antioxidant capacities of black rice might be constituted from anthocyanin and flavonoids through their significant correlation. Additionally, the antioxidant capacities of red rice was possibly contributed from phenolic compound due to their high correlation. However, most functional components and antioxidant capacities decreased. The functional components probably depleted for scavenging radicals which were produced during germination, so the antioxidant capacities declined as well. The GABA content of brown rice significantly raised after germination. The HLB germinated rice had highest GABA content. To sum up, it is recommended to cultivate XPR for higher total phenolic content and better yield with 140 kg ha -1 nitrogen fertilizer application, and cultivate XPB for higher GABA content and better yield with 70 kg ha -1 nitrogen fertilizer application.
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