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|標題:||The development of a lycopene extrudate and the analysis of its anti-oxidative properties|
Lycopene was used as an additive to produce a rice snack food by using a single-screw extruder and the anti-oxdative properties of extrudates were analyed. Two experiments were designed in this research. In the first experiment, the response surface methodology was used to investigate the effects of operation variables (screw speed, moisture content and tomato powder content) on extrudate's physical properties (expansion ratio, bulk density, shear force, hardness and moisture content) and chemical properties (degree of gelatinization, water solubility index, water absorption index) and then the extruder's optimum operation conditions were developed.The experiment results showed that: 1. The extrudate's radial expension ratio increased with increasing screw speed, and then decreased gradually. The extrudate's longitudinal expansion and water absorption index decreased with increasing screw speed, and then increased gradually. 2. The extrudate's radial expension ratio and degree of gelatinization increased with moisture content of raw material, and then decreased gradually. Increasing the moisture content of raw material increased the extrudate's moisture content, bulk density, shear forces and hardness, but decreased longitudinal expansion, water solubility index and water absorption index. 3. The extrudate's radial expension ratio decreased with increasing tomato powder content and then decreased gradually. The extrudate's longitudinal expansion decreased, but shear fores and hardness increased with increasing tomato powder content. 4. The extrudate's optimum operation conditions found through the response surface methodology in this study were that moisture content of raw material between 12.3% and 12.8%, ratio of tomato powder between 23.6% and 26.2% under 250rpm screw speed. 5. An experiment was taken to testify the response of dependent variables under the conditions (12.5% moisture content and 25.0% tomato powder). The results showed that there were no significant differences between the regression and experiment results. According to the obove results, it was showed that the optimum operation conditions in this study were suitable for the production of tomato snack food. At the second experiment, the optimum operation variables were 1000C die temperature, 12.5% moisture content, 25.0% tomato powder and 250rpm screw speed. The corn grit (75%) with tomato powder (25%), rice grit (25%) and buckwheat grit (25%) were used to investigate the antioxidative function. The antioxidative characteristics such as inhibition on hydroperoxide, formation of conjugate diene and liposome oxidation, scavenging DPPH radical, superoxide anion and hydrogen peroxide ability, ferrous ion chelating power and reducing power for all the treatments of raw materials and extrudates were determined. BHA and α-tocopherol were added as the controls for the experiment. The experimental results showed that: 1. For the inhibition on hydroperoxide and formation of conjugate diene, extrudates with the tomato powder reached the highest; extrudates with the buckwheat powder was the second, as well as extrudates with the rice powder reached the lowest. With the increase of time, inhibition of extrudates with the buckwheat and rice powder decreased, but extrudates with the tomato powder were different. For inhibition on liposome oxidation, extrudates with the tomato powder and buckwheat powder had no significant differences, as well as extrudates with the rice powder reached the lowest. 2. Extrudates with the tomato powder in scavenging DPPH radical ability such as the superoxide anion scavenging ability, scavenging hydrogen peroxide ability, ferrous ion chelating power and reducing power. surpassed extrudates with other additives. 3. There were no significant differences on the inhibition on hydroperoxide, formation of conjugate diene and liposome oxidation, scavenging hydrogen peroxide ability and reducing power between extruded and non-extruded treatments. There were significant differences on scavenging DPPH radical ability etc. The extruded samples had the lower scavenging DPPH radical ablity, however, the higher scavenging superoxide anion and ferrous ion chelating power.
|Appears in Collections:||生物產業機電工程學系|
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