Durian Ripeness Instrument

Google Tricorder.

Since there is no consensus opinion on the preferred ripeness at the time of harvest, the instrument you request would be subjective in nature....That requires a design of your own specifications, and alas, you have given none....

"Ripeness and selection

A customer sniffs durian before purchasing it.

According to Larousse Gastronomique, the durian fruit is ready to eat when its husk begins to crack.^[34] However, the ideal stage of ripeness to be enjoyed varies from region to region in Southeast Asia and by species. Some species grow so tall that they can only be collected once they have fallen to the ground, whereas most cultivars of D. zibethinusare nearly always cut from the tree and allowed to ripen while waiting to be sold. Some people in southern Thailand prefer their durians relatively young when the clusters of fruit within the shell are still crisp in texture and mild in flavour. For some people in northern Thailand, the preference is for the fruit to be soft and aromatic. In Malaysia and Singapore, most consumers prefer the fruit to be as ripe and pungent in aroma as possible and may even risk allowing the fruit to continue ripening after its husk has already cracked open. In this state, the flesh becomes richly creamy, slightly alcoholic,^[27] the aroma pronounced and the flavour highly complex.

The various preferences regarding ripeness among consumers make it hard to issue general statements about choosing a "good" durian. A durian that falls off the tree continues to ripen for two to four days, but after five or six days most would consider it overripe and unpalatable.^[35] The usual advice for a durian consumer choosing a whole fruit in the market is to examine the quality of the stem or stalk which loses moisture as it ages: a big, solid stem is a sign of freshness.^[36] Reportedly, unscrupulous merchants wrap, paint, or remove the stalks altogether. Another frequent piece of advice is to shake the fruit and listen for the sound of the seeds moving within, indicating the durian is very ripe and the pulp has dried out a bit.^[36]"

^{http://en.wikipedia.org/wiki/Durian#Ripeness_and_selection}

On a branch? your asking for allot!

You'll have to do your own googleing for that.

But,

For fruit and vegetables the use a color sorter utilizing CCD technolgy.

The can also do a quality check for imperfections such as bruising and such.

These work at extremely high speeds in canning operations.

Colour as a signal of ripeness

Key

Buhler Group

The other way is to check the brix of the fruit, This is pretty accurate and simple. but not automated....that I know of.

And that is to use a refractometer