Food Science
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I am doing a titration to analyse the effect of heating time on the Vitamin C content of broccoli. I have worked out how to do the titration, however, I was wondering what would be the best way to prepare the broccoli?
Each sample will be blanched to ensure that the cooking time is accurate. If I put the cooked broccoli in a blender, would this puree be appropriate to use in my titration? Or would I need to sieve the pulp to extract the juice?
I'm just worried about the effect that the colour may have on determining an end-point. 260308
Igloo writes ...
Yes, you do need to put your cooked broccoli in a blender to ensure that all available vitamin C is removed from the plant material, and yes, you will need to “sieve” this mixture, otherwise the titration end-point will be very difficult to see.
I suggest that you use a fine muslin, rather than a sieve. Place the muslin in a large funnel, pour the puree through, and collect the relatively clear filtrate in some sort of large vessel, e.g. a large measuring cylinder. When the filtration is complete, the muslin can be squeezed to remove any last traces of liquid. Water can be poured into the funnel to wash any further vitamin C through into the filtrate, and the squeezing technique repeated as necessary.
Always carry out a risk assessment and check with your teacher before starting any practical work.
Risk assessment
Before attempting any practical work based on the advice and suggestions on this website, you must do the following. Identify any hazards, assess the risks from these hazards, and then decide appropriate control measures to reduce the risks. You must have these approved by those in authority in your school or college laboratory. Do not rely on what is said on this website.
For further guidance see our tutorial on Risk Assessment.
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updated: 29 March 2008
