碩士 / 國立臺灣大學 / 食品科技研究所 / 103 / Pullulan is an extracellular microbial polysaccharide produced from Aureobasidium pullulan. The basic unit of pullulan is maltotriose which is linked by α-1,6 glycosidic bond. Pullulan is highly water soluble but with low oxygen permeability, good film-forming, and adhesive properties. In addition, pullulan also exhibits good biocompatibility as well as great biodegradability. Because of those material properties mentioned above, pullalan has been applied in many fields such as denture adhesive, pharmaceutical coating, edible food coating and others. Since global warming and energy crisis are getting more and more attention, developing eco-friendly food package materials like polylactic acid (PLA) also arouse people’s interests. In this study, trisodium trimetaphosphate (STMP) was used as a crosslinking agent to improve the water resistance and physical properties of pullulan. In addition, nisin, a bacteriocin that produced by Lactococcus lactics, was incorporated into the pullulan film to develop an antibacterial food package system. The antibacterial activity of active pullulan film was also tested for common strains: E. coli, S. aureus, L. monocytogenes and V. parahaemolyticus. utilizing in vitro and on the meat. The water resistance was improved significantly since the weight loss could be reducing to 22% when concentration of STMP at 20 mg/ml, and the swelling degree was also increased to 73.16 g/g. The decreasing O-H stretching vibration(3300cm-1) of crosslinking pullulan in FT-IR spectra indicate a higher degree of crosslinking was formed with increasing concentration of crosslinking reagent. In the drug released test, bovine serum albumin releasing rate was higher in the 20 mg/ml STMP than other groups. In the antimicrobial activity test using dynamic shake flask test, nisin and EDTA incorporated pullulan hydrogel could at least reduce 1.12 and 2.72 Log cfu in the S. aureus and L. innocua. In the gram negative bacteria E. coli and V. parahaemolyticus, there were also 1.06 and 1.01 log inhibition in total cfu counting. In the frozen tilapia food package, frozen tilapia with active pullulan package could surely inhibit the growth of L. innocua and V. parahaemolyticus. In summary, the crosslinking strategy effectively improve the hydrophobic property of pullulan, and expect the active pullulan-nisin absorbend pad could apply to food package to extend the shelf life of meat.
| Identifer | oai:union.ndltd.org:TW/103NTU05252012 |
| Date | January 2015 |
| Creators | Yi-Tsun Huang, 黃奕尊 |
| Contributors | Kuan-Chen Cheng, 鄭光成 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 115 |
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