博士 / 國立海洋大學 / 食品科學系 / 88 / Abstract
In order to elucidate the physiological properties and the application feasibility on the food processing of lyophilized extracellular mucilage powder (LEM) prepared from Klebsiella oxytoca CF154, the physiological properties comprised of the solubility, relative viscosity, emulsifying stability, toxicity test, effects of different sugar source in medium on the LEM yield, and the improving effect of gel-forming ability on the mackerel surimi of LEM were investigated. K. oxytoca CF154, isolated from the surface of a wooden fishing boat in Taiwan, is a gram-negative, nonmotile, catalase (+), short rod (1.78 mm x 0.66 mm) aerobe which produces a yellowish, round, and ropy colony on marine agar plate.
LEM was recovered from K. oxytoca CF154 cultured in mucous screening basal broth (MSBB) and the yield was approximately 0.08% (0.75-0.80 g LEM in a liter cultural broth). While the concentration of LEM in deionized water (pH value 6.6 was lower than 0.6% (w/v) at temperature from 10.0oC to 80.0oC, the LEM solution existed as a soluble and homogeneous suspension. Relative viscosity (RV) increased as the concentration of LEM solution increased from 0.0 to 0.5%. Factors affecting viscosity of 0.2% LEM solution showed that the RV was stable over a pH value range from 4.0 to 9.0. However, the RV of 0.2% LEM solution decreased as the temperature increased from 10.0 to 80.0oC. Although the higher NaCl concentration (0.0-5.0%) in LEM solutions was, the lower RV of LEM solutions was. The emulsifying ability and emulsion stability of 0.2% LEM emulsified solutions could reach 56.0-60.0% in a pH value range from 3.0 to 9.0 and in 0.02-1.00% NaCl concentration. The evidence of 0.2% LEM emulsified solution showed to the resistance on acids and salinity was obtained. Results from Sephacryl S-400 gel permeation chromatography (GPC) indicated that LEM is a mixture of protein-polysaccharide complexes of which the dominant fraction (85.0%) has a molecular weight in the range of 1.5-1.8 x 106 Da (1.5-1.8 MDa). In the polysaccharide moiety, HPLC analysis suggested that the major sugars in this dominant fraction were mannose, galactose, glucose, and arabinose in the ratio of 13.2 : 5.0 : 1.9 : 1.0. In addition, there exists uronic acid at 6.3% in this dominant fraction. The results of sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) indicate that protein in this dominant fraction consist of five protein subunits, which had a molecular weight as 35.9, 34.8, 30.7, 23.0, or 19.0 kDa.
Effects of the replacement of sucrose with either maltose or mannose in MSBB on the LEM yield, the efficiency of sugar conversion, monosaccharide composition, and their relative viscosity of the LEM from K. oxytoca CF154 culture were investigated. The yield of the LEM made from maltose-MSBB was the highest (1.75 g/l), and followed by sucrose-MSBB (0.98 g/l) and mannose-MSBB (0.53 g/l). The efficiency of sugar conversions of the LEM prepared from three carbon source of MSBB were found to following the order of maltose-MSBB (35.01%) > sucrose-MSBB (33.17%) > mannose-MSBB (11.89%). 0.2% LEM solutions from three media showed that the exhibition of RV have the same tendency over a pH range from 4.0 to 9.0, temperature increased from 10 to 80oC, and in NaCl concentration (0.0-5.0%). The dominant fractions relating viscosity of 0.2% LEM from three media were analyzed, and the major monosaccharides present in this dominant fraction were mannose, galactose, glucose, and arabinose which were the same in three LEM samples. Accordingly, the major biosynthetic pathway of the LEM from sucrose, mannose, or maltose might be the same by K. oxytoca CF154 using these three sugars as the sole carbon source.
In order to investigate the toxicity of the LEM prepared from K. oxytoca CF154, the rats (Wistar rat, male) were used in the animal test for the evaluation of biochemical toxicity. The results suggested that while the LEM were utilized in the level below 3.0% in the feed, the biochemical toxicity of the LEM did not exhibit on the male Wistar rats.
The feasibility of the LEM, used as a quality improvement agent for mackerel surimi, prepared from the strain CF154 was studied. The results indicated that the best application of the LEM on the mackerel surimi was using 0.25% LEM and 8.00% potato starch to mixing with mackerel meat paste and then setting at 4.7oC for 8 hr. After boiling water treatment, the mixed mackerel surimi showed the gel strength as 495 ± 12 g x cm (breaking force, 550 ± 11 g; breaking point, 0.93 ± 0.02 cm), whiteness index was 53 ± 1, and folding test as A grade. From the observation of the DSC thermograms, the endotherm peaks of myosin of mackerel and LEM was found to shift to low temperature owing to conjugate between myosin of mackerel and LEM. In addition, the electrophoresis pattern of total salt soluble proteins (TSSPs) from the mackerel surimi, accordingly, it was suggested that TSSPs from the mackerel surimi might be interaction with LEM.
| Identifer | oai:union.ndltd.org:TW/088NTOU0253041 |
| Date | January 2000 |
| Creators | Fu-Jin Wang, 汪復進 |
| Contributors | Ching-Shyong Wu, Chrong-Liang Pan, 吳清熊, 潘崇良 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 143 |
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