jueves, 7 de mayo de 2009

Practise 3: Starch determination



As well as the sugars in the plants there are glucides polysaccharides like the starch, the substance that will be obtained from the pulp. That substance is the reserve of a lot of the plants.


1- To obtain a sample to compair with, we will take a potato, that is rich in starch. After chopping the potato by the middle and to cut it, we throw some drops of lugol. That colouring dyes purple the starch.


2- We take now an olive, we take off the pulp and we mince it.


3- When the pulp of the olive is minced, we throw some drops of lugol.


4- Conclusions: we can't see very well the purple colour because the olive pulp is too dark. But it is rich in starch, so it colours.

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