Effects of Extrusion Processing on the γ-Aminobutyric Acid Content and Physicochemical Properties of Germinated Brown Rice
| Autor: | Yi-Fan Lai, 賴羿帆 |
|---|---|
| Rok vydání: | 2013 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 101 Germinated brown rice is known for the rich γ-aminobutyric acid (GABA). The GABA has not only many physiological functions such as preventing Alzheimer’s disease and atherosclerosis, depressing blood pressure etc., but also has a high thermal stability of the characteristics. Extrusion technology with advantages of high temperature short time, continuous, high productivity, and high energy efficiency is said to be one the state of the art technologies. A factorial design was employed to investigate the influence of germinated brown rice types (Kaohsiung 145, Tainan 11, and Tainung 71), die temperature (100, 110, and 120℃) and screw speed (200, 300, and 400 rpm) on the GABA content and physicochemical properties of germinated brown rice. Results of the study showed that GABA contents in Kaohsiung 145 of germinated brown rice were significantly (p &;lt; 0.05) higher than Tainan 11 and Tainung 71 of germinated brown rice after extrusion processing. The die temperature and screw speed had no significant (p＞0.05) effect on the GABA content. With an increase on die temperature and screw speed, there was a concomitant increase on water absorption indices, swelling power and a decrease on water solubility indices. With an increase on screw speed, there was a concomitant decrease on hardness, maximum shear force and bulk density. Results of the variance analysis showed that the die temperature had the significant correlation (p &;lt; 0.01) with the properties of water solubility indices, water absorption indices, swelling power, radial expansion and longitudinal expansion after extrusion. On the whole, the results showed that GABA content in germinated brown rice extrudates was not difference from the unprocessed germinated brown rice. When the geminated brown rice Kaohsiung 145 was extruded by die temperature 110℃ and screw speed 300 rpm, its extrudate had the highest GABA content (17.10 mg/100 g dw). |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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