| Summary: | 博士 === 國立臺灣大學 === 植物病理與微生物學研究所 === 94 === During the production process of the germinated brown rice, several factors must be considered, including the cultivar of the rice, germination activity of seeds, sprouting temperature, sprouting time, the control of microorganisms and accumulation of main functional composition. The control of microorganisms and food safety are very important, especially the disinfection method that does not impair the sprouting capability while meeting food safety. To this study, the available control methods that meet food safety requirements are limited. Given the concerns of the consumers, traditional food additive is not acceptable. Therefore, this study used ultrasonic technique for surface cleaning, and UV disinfection in combination with 0.6 ppm O3 and circulating water to control the total count of microorganisms in soaking water to under103 cfu/ml. The aflatoxin test conducted under such conditions did not detect the presence of aflatoxin, which meets the food safety standard. Among the selected seven rice cultivars tested under different temperatures, TK-8 was rated the best sprouting process and taste after soaked for 24 hours at 37℃, and the accumulated GABA reached as high as 31.12 mg/100g.
A combinatory fermentation, combined with germinated brown rice as a functional cultural precursor, was processed using Bacillus natto SYH-MT 0379 as the solely strain in performing solid-state and liquid batch fermentation in search of new active functional substances. In the screening experiment, the antimicrobial and antioxidant activity tests were chosen as the testing models. After filtration the fermentation broth was successively with n-hexane, ethyl acetate and methanol to be present in the ethyl acetate fraction. The active compounds were found extracted TLC together with HPLC analytical program was applied for comparison study and the resulting HPLC profile showed a newly generated absorption peak. After repeated TLC separation, the single substance, named PGBRNFL-I, were found in the ethyl acetate fraction. The characteristics of the compound exhibited the fluorescence signal at UV 254 and 365 nm and the biological functions of antimicrobial (mainly against Candida albicans) and antioxdant (mainly scavenging the DPPH radical) activity. Neither the germinated brown rice itself nor the combinatory fermentation of the germinated brown rice/Bacillus natto system has been reported previously. Up to now, this is the first study dealing with the theme. The spectroscopic data for PGBRNFL-I have been collected including ultraviolet (UV) spectrum, infrared (IR) spectrum, as well as 1-D 1H and 13C, 2-D 1H-1H and 1H-13C COSY nuclear magnetic resonance (NMR) spectra. In addition, an electron impact mass spectrum (EI-MS) was measured to elucidate the molecular fragmentation and its molecular weight. The structure determination by the information of the related spectroscopic data is now undergoing.
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