| 英文摘要 |
The authors have made an attempt to develop a practical method for the separation of bromelain and starch from pineapple stems. The bromelain was obtained either by the acetone method or by the tannic acid method. Results showed that most bromelain was precipitated in the 40-50% acetone concentration, also that most bromelain was precipitated when 2-4 g of tannic acid were added per liter, under these condition the highest specific enzyme activity was obtained. The biochemical properties of crude enzyme were: optimal temperature 57°C; optimal pH 7.0; while Zn++ inactivated and Mg++ activated it to the highest degree. Crude bromelain was made to separate the components by means of disc-electrophoresis. Six bands can be recognized in the zymographs, whether the bromelain was obtained by the acetone method or tannic acid method. The pineapple stem starches are spherical g r an ules of about 11µ in diameter. Although the granules are easily broken, a typical granule has a Y-shaped fissure in its central area. Using chloral hydrate technique to prepare amylose and amylopectin and direct scale readings of a mixture of amylose and amylopectin, the results indicated that the amylose content of pineapple stem starch is 36%. |
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