| Summary: | 碩士 === 國立海洋大學 === 食品科學系 === 89 === Pseudomonas vesicularis MA103 is a marine bacterium, which has the ability to degrade agar. As P. vesicularis MA103 was incubated in MM-P broth, containing 0.15% agar, 0.1% yeast extract, 1.0 mM CaCl2, 1% b-glycerophosphate and 0.6% NaCl, at 26oC with shaking speed of 120 rpm, the cultured broth could reach 98.30 unit/mL agarase activity and pH value of 6.21 after 48 hr. P. vesicularis MA103 was cultivated in various incubation conditions as (1) 500 mL MM-P broth in a 1 L fermenter, (2) 3 L MM-P broth in a 5 L fermenter, or (3) 3 L MM-P broth with controlled pH value at 6.20 in a 5 L fermenter. While being cultivated in (1) 500 mL MM-P broth, strain MA103 performed 51.91 unit/mL agarase activity. As incubated in (3) 3 L MM-P broth, strain MA103 achieved a higher agarase activity, 101.20 unit/mL.
Total carbohydrate contents of algal polysaccharides that extracts from Gracilaria, Porphyra dentata, and Monostroma nitidium with different methods are ranged from 23.34 to 49.25%. The highest content of sulfate (1.41%) was observed in the polysaccharides extracted from Porphyra dentata as treated with hot water. The highest content of 3, 6-anhydro- galactose
(31.26%) was revealed on the polysaccharides extracted from Gracilaria as treated with enzymes or mixture. The highest yield 50.16% of polysaccharide extract was obtained when Porphyra dentata was treated with enzymes or mixture. Total sugar contents of oligosaccharide lysates derived from algal polysaccharides extracts following digested by P. vesicularis MA103 agarases at 26oC for 48 hr are ranged from 5.74 to 31.26%. Molecular weight of the oligosaccharide mixture, derived from eight algal polysaccharides extracts that digested by P. vesicularis MA103 agarases at 26oC for 48 hr, were determined by the gel permeation chromatography (with Sephadex G-10) are in the range of 292.0 - 1689.6 Da.
In the experiment of emulsifying properties of algal polysaccharide extracts, as the concentration of algal polysaccharide was increased from 0.0 to 1.0% (w/v), the emulsifying activity of the reacting mixture was also increased. When 1.0% polysaccharide extract, derived from Porphyra dentata with hot water treatment, were added to the emulsifying mixture, the best performance of emulsifying activity and emulsion stability were measured as 100% and 90%, respectively. Porphyra oligosaccharide mixtures, which obtained from the porphyral polysaccharide extract with enzyme or hot water treatment followed by digested by P. vesicularis MA103 agarases, were added (2.0%) individually to the emulsifying reacting solution, and the resulting emulsifying activity was 52.63 and 56.25%, repectively. The emulsifying activity of the rest oligosaccharide mixtures were measured between 45.00 and 46.66%. As to the emulsion stability, various oligosaccharide lysates did not show significant differences, which are among 40.00 and 46.15%.
After dehydration under 60oC for 8 hr, eight algal polysaccharides extracts showed the capability of film formation. The higher penetration force (796.96 g) was observed happened on the film made by the polysaccharide extract derived from Gracilaria that treated with enzymes. Among various oligosaccharide hydrolysates, film made by oligosaccharides derived from Gracilaria polysaccharide extract treated with enzyme and then digested by P. vesicularis MA103 agarases, showed a higher penetration force (288.66 g).
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