| Summary: | 碩士 === 國立高雄海洋科技大學 === 水產食品科學研究所 === 101 === There are large amounts of waste such as fish skin,fish scales and fish bones produced in the factory of fish fillets, however, this waste has not been utilized well. The extruders have advantages of wide range operability of raw materials, continuous production, high productivity, less waste produced and low cost during the process. The high temperature and high pressure generated by extrusion process helps to improve the extraction efficiency of collagen from fish scale. In this study, we investigated the effect of screw speed, feed rate, moisture content of raw materials, oil content of raw materials, barrel temperature and die design on extraction efficiency of collagen from extrudate of Taiwan tilapia and milkfish scale and application. The optimal and operable extrusion conditions for Taiwan tilapia scale are screw speed 360 RPM, feed rate 11.2kg/hr, moisture content of raw materials 27% and die openings 3、4、5mm. Using SDS-PAGE, the α1 and α2 chains (95 - 130 kDa molecular weight) of typeⅠcollagen extracted from Taiwan tilapia scale extrudate could be found. Among different extrusion conditions, the amount of water-soluble proteins extrudated from fish scale extrudates increased around 3-8% compared with control. Moreover, NaOH-treated fish scale extrudates possessed higher levels of protein extraction rate than that of non-NaOH -treated group. Considering the reduction of operating cost and usage of chemicals, 50℃hot water was used to extract water-soluble proteins from fish scale extrudates. In view of application, the collagen extracted from fish scale extrudate has bloom value 147, and which can be used as a food additive. The collagen also possesses 43% moisture absorption capacity and 63% moisture retention capacity, which are comparable to that of commercialized collagen, and can be served as raw materials for cosmetics.
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