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  • John Goodwin

Lab work...PPO

So..having collected clover samples all summer, I have started my lab work by looking at an enzyme called polyphenol oxidase (PPO). This is the same enzyme that causes apples and bananas to go brown when you cut them. When biorefining red clover, PPO is undesirable as it reacts with the isoflavones and stops their oestrogen-like effect.


We start by grinding the clover samples in liquid nitrogen (very cold indeed, -200 degrees C!)

Then we stop the enzyme from working by adding vitamin C. Some colour differences between varieties are visible when processing, which may or may not be due to PPO


Then, after cleaning the enzyme up, we add a substance for the enzyme to act upon (the substrate). We load it in a spectrophotometer which is a machine that measures changes in colour. The software gives us a graph of enzyme-substrate reaction rate kinetics, which basically tells us how much potential a certain variety has for biorefining (in terms of PPO activity).


I wonder how many commercially available red clover supplements have taken the effects of PPO into consideration? If they have, they haven't published it!

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