Grapes

[Bazile]

How unusual is it for there to be a green grape in amongst a bunch of red grapes ?

In this case a much smaller green grape attached to the bunch

[theprof]

It's an immature grape Bazile. All grapes start off green before the anthocyanins produce the final skin colour. The rate at which these anthocyanins work is variable and it's likely that the green grape was the slowest to develop. That ties in with it's size. A further possible reason is that dark skinned grapes are notoriously unstable genetically and you can sometimes get some on a bunch that are green in colour. In your case, the size of the grape points to immaturity though.

[theprof]

All grapes are green inside and you can sometimes see the colour developing in the "skin" of a small red grape variety when it's on the vine and still green in colour.

[Bazile]

Thanks prof

A greenhorn ,then :-)

[theprof]

That's right Bazile. The baby of the bunch!

I meant to say in my last post that you could see the colouration developing if you cut the green grape in situ on the vine and looked closely just beneath the skin.

[Bazile]

So what determines if a vine produces green or red grapes ?

[theprof]

The genetic make-up of the grape variety. The colouring agents in dark skinned grapes are called anthocyanins. Green varieties of grapes do not produce the required anthocyanins due to a gene mutation. Because of this, they have a light skin.

It is these same anthocyanins that are responsible for the colour of blackcurrants, raspberries, blueberries and a whole host of fruit and vegetables.

[Bazile]

Thanks