| Summary: | 碩士 === 國立澎湖科技大學 === 食品科學研究所 === 102 === Brown rice is simply white rice that has intact bran covering the rice grain , it is a much better source of fiber compared to white rice. Brown rice contains many minerals such as iron and magnesium, as well as vitamins and cellulose, which help to lower LDL cholesterol. Brown rice is more nutritious than well milled white rice；however ,the outer seed coat contributes a definitely different texture which is disliked by many consumers.
Non-thermal plasma can produce very efficient sources of active species in air or in another gas or gas mixtures at atmospheric pressure. This project will utilize a dielectric barrier discharges system with adjustable frequency and voltage to produce non-thermal plasma at atmospheric pressure, in order to understand the mechanism influencing brown grain rice.
In this study, two different kinds of brown rice: Taichung Taikeng 9(TK9) and Taichung Sen 10(TCS10) were chosen for the samples, and then underwent optimum conditions of processing with non-thermal plasma at atmospheric pressure. This was followed by measuring its cooking time；texture analysis was observed via scanning electron microscope. Finally, dynamic rheological continuous pasting viscosity (RVA) and fine structure analysis were carried out to understand the nature of starch.
The results showed that after the plasma treatment, for the two brown rice types TK9 and TCS10 the cooking time was decreased. From the texture analysis regarding the hardness measurement values of the two varieties of rice, after plasma treatment, showed a downward trend；continuous pasting viscosity found that, the peak viscosity maintained its strength. The final viscosity of TK9 showed a rising trend, and for TCS10, a downward trend；as for the fine structure , after plasma treatment, the physical etching of the starch granules showed that they were fragile, resulting broken molecules causing the peaks to extend.
Utilization of the novel non-thermal plasma technology in the whole grain processing can provide better mouth feel and shorter cooking times.
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