碩士 / 國立海洋大學 / 食品科學系 / 87 / Abstract
The objectives of the study are to explore the feasibility of using same molecular weight (Mw), but different degree of deacetylation (DD) or using different Mw but same DD water-soluble chitosans to prepare active package with antioxidation activity to be used in mullet roe storage. Chitin was prepared from shrimp (Solenocera prominentis) processing waste by chemical process and then alkali (140℃, 50 % NaOH) deacetylation for various time to obtain different Mw (5,100、3,200 and 1,800 kDa), different DD (68%、82% and 87%) water-soluble chitosans. Two similar Mw (2,000 and 1,000 kDa) and three different DD (68%、82% and 87%) chitosans were prepared by microfluidizing treatment upon the above-mentioned chitosans. Chitosan membrane are made by casting the above 6 water-soluble chitosans (2%, w/v) 0.2 M acetic acid solutions. External active pack was prepared by enbedding BHA (Butylated hydroxyanisole) between chitosan membrane and PET (polyethylene terephalate) membrane then themal sealed with polyether along the edge. Mechanical properties of tensile strenght and tensilc elongation were measured with a rheometer. Release rate of antioxidant is calculated from the changes of antioxidant concentration after immersion chitosan-PET menbrane in gycerol for various time. The results shown the relase rate of BHA (200 ppm/cm2) from chitosan-PET (polyethylene terephalate) membrane increased with increasing DD and decreased with increasing Mw of chitosan used. It might be due to pore size and hydration differences resulted from using different DD and/or Mw of water-soluble chitosans respectively. The tensile strength increased with increasing Mw or with decreasing DD of water-soluble chitosans. It may be because of the higher Mw chitosans entangle easier whereas higher DD chitosans form more crystalline region. The ductility decreased with decreasing Mw and also increased with decreasing DD.
Results of water-soluble chitosan solution (0.5%, w/v) containing different concentration (0.1% vs 0.2%) BHA to be used as an internal active package either with or without vacuum package shown alleviation in lipid oxidation increased with increasing BHA concentration. However, the alleviation in discoloration did not show significant difference among treated or control sample.
| Identifer | oai:union.ndltd.org:TW/087NTOU0253032 |
| Date | January 1999 |
| Creators | Ging Chung Yu, 俞景中 |
| Contributors | Rong Huei Chen, Hong Ming Cheng, 陳榮輝, 鄭弘命 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 76 |
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