| Summary: | 碩士 === 國立臺灣海洋大學 === 食品科學系 === 102 === The aim of this study was to fractionated chitosan hydrolyzate by enzyme treatment by supercritical carbon dioxide (s.c. CO2), and establish the degree of polymerization divided chitinous oligosaccharides. In this experiment, 50 mL of chitosan hydrolyzate was treated by supercritical carbon dioxide at different temperatures (35, 45, 55℃), pressure (20, 30, 40 MPa) and time (60 min, 120 min). The chitosans hydrolyzate in the collection vessel and the extraction vessel were precipitated with methanol to obtain a supernatant and sediment and determine the properties of two parts. The results showed that the enzyme treatment to six hours of chitosan hydrolyzate containing a large molecular weight range of the low degree of chitinous oligosaccharides, for the division after supercritical conditions better, and to add volume ratio of 1:5 of methanol more distinguishable than the polysaccharides and oligosaccharides. That the extraction yields can be based on the operating conditions of the collection vessel for 60 minutes, in an extraction temperature of 45℃ has the best extraction rate; the operating conditions in the extraction yields in the extraction vessel is 60 minutes, the optimum temperature and extracted with 55℃. The molecular weight, the effect of the collection vessel and extraction vessel, at the extraction time - 60 minutes, which are positively correlated with the molecular weight of the pressure and the temperatures, both of them have increased to enhance the tendency. The molecular weight of the collection vessel is less than the molecular weight of the extraction vessel. But polydispersity has no significant change. Saccharide part is in the 60 minutes, three temperature, 20 MPa in the collection vessel has found one type of sugars. The types of the oligosaccharide in the collection are mostly less then chitopentasaccharide.
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