Discussions on the preparation and physicochemical properties of carboxymethyl agar
| Autor: | Yi-Lin Lee, 李宜霖 |
|---|---|
| Rok vydání: | 2019 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 107 The water solubility of dietary fiber affects its physiological activity and further causing the differences when applied in the food industry. As compared to insoluble dietary fiber, soluble dietary fiber has more function in the food industry, especially the beverage industry. Thus, increasing the solubility of dietary fiber was the aim of this study. Carboxymethylation is one of the common method to increase the water solubility of dietary fiber. In addition to changes in physical properties, carboxymethylated dietary fiber may cross link with other polymers to form a network structure. This study uses agar, which is insoluble at room temperature, as the experimental sample. Firstly, the effects of physical properties of CMA were analyzed with different alkali concentration. Then, CMA samples were further cross linked with CMC to form composite hydrogels, while investigating the effects of degree of substitution. Lastly, the influences of adding CMA samples and cross linked powder to baked samples were compared and discussed. The results showed that the degree of substitution of CMA samples increased with the increase of alkali concentrations. The water solubility of CMA samples was related to the degree of substitution. When 30% alkali was applied, the degree of substitution of CMA sample reached the highest (0.52) and CMA sample was completely soluble in water. The degree of substitution of CMA could not be effectively improved even when higher alkali concentration was used. In the preparation of composite hydrogel, the ratio of CMC to CMA and the degree of substitution of CMA samples were both related to cross linking structure of hydrogel. The composite hydrogel prepared with the ratio of CMC to hCMA at 1:0.5 had the highest rate of water absorption and the lowest rate of degradation. The controlled release effect of composite hydrogel was better than that of the CMC hydrogel in acid (pH 2.2) and weak base (pH 7.4) environments. The effects of hCMA powder and cross linked powder on baked products were also compared in this study. The results indicated that both samples could reduce the rate of water loss of fresh samples. During storage, cross linked powder had better ability to retard hardening rate of baked samples. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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