| Summary: | 碩士 === 國立宜蘭大學 === 生物機電工程學系碩士班 === 100 === Sulfur dioxide was used in the process of dried daylily production, in order to improve the product color and texture and to extend the shelf life of dried daylily product. This study was to investigate the status of sulfur dioxide residue in the process of dried daylily production which using various daylily samples with different varieties, origin, processing method and sulfur dioxide residue.
Besides, the dried daylily products with various packaging materials and methods were stored at 25℃ room temperature for 12 months, in order to investigate whether those factors affect the quality of dried daylily products or not.
In the processing of daylily using fumigation or soaking methods, the total sulfur dioxide residue decreased, the ratio of free type sulfur dioxide declined gradually, and the ratio of bond type sulfur dioxide increased gradually. The dried daylily product made by fumigation method contained 90% of bond type sulfur dioxide residue, but for product made by soaking method contained only 80% of bond type sulfur dioxide residue. The variety and processing method significantly affected the color of dried daylily products.
However, the most important factor to the quality of dried daylily product ion was variety, the other factors would be sulfur dioxide residue and processing methods. The origin of daylily material did not affect the product quality. The texture was significantly affected by the daylily variety. The texture of plain variety was harder than the high mountain variety. The re-hydration ability was significantly affected by the processing method. The daylily product made by soaking method had better re-hydration ability.
For most of the dried daylily products, the product color changed significantly after 12 months storage. The aluminum foil package had better light blocking and airtight properties, so the color of sample packed with aluminum foil did not change significantly.
OPP/CPP package had good gas permeability. When oxygen absorber and nitrogen filling were used in OPP/CPP package, there was no significant effect on the color of dried daylily product. When sulfur dioxide emitter used in the package, the dried daylily product made by soaking method has better color, but not for the product made by fumigation method. Besides, when sulfur dioxide emitter used in the package, it would cause yellowish-brown color on the surface of package. This may affect the desire to purchase for the consumer. Therefore, the aluminum foil package was recommended for the dried dayliliy product when stored at room temperature.
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