Why Cucumbers taste bitter and some more…

A cool cucumber slice.

For the scientifically inclined, Cucumber is a fruit and it couldn’t have been more cooler. But this cool fruit sometimes can taste as bitter as a bitter gourd!

But why?

Blame it on a natural organic compound Cucurbitacin (which might be a promising target for Cancer therapy) which is produced by various plant species and function as a protection mechanism against herbivores (acting as taste deterrent). They are generally restricted to stem, root, leaves of a plant but may spread to the fruit creating trouble for mortals. Now there are two notorious compounds specifically Cucurbitacin B (also found in bitter gourd) and Cucurbitacin C which makes our fleshy green fruit taste bitter and makes people read this kind of blog post.

Several factors have been attributed as to why this compound reach the fruit and what steps could be taken while cultivating cucumber to avoid that. But knowing what causes above compounds to infuse bitterness in the innocent fleshy fruit can be interesting. Actually it’s us, who find cucumber bitter so something must be responsible inside us too.

We have bitter taste receptors on our tongue which on stimulation sends the “bitter” signal to our brain. So only those compounds which stimulate these receptors will taste bitter to you. There are around 25 such receptors which are part of TAS2R (Taste 2 receptors).

Reference: HUGO Gene Nomenclature Committee at the European Bioinformatics Institute

Quoting from the reference article[⁴]

TAS2Rs are responsive to numerous compounds at low concentrations and exhibit overlapping specificities, with most receptors responsive to multiple compounds and many compounds capable of stimulating multiple receptors. A striking proportion of their agonists are toxins originating in plants, suggesting that the native biological role of TAS2Rs is to detect noxious substances in potential foods, preventing overexposure.

So if you somehow inhibit receptors which are responsive to Cucurbitacin, you won’t find cucumber bitter, ever. This is a sure shot method than the ones suggested in articles like this but not an easy/practical way.

References & External Links:

https://academic.oup.com/chemse/article/41/8/649/2452820/Copy-Number-Variation-in-TAS2R-Bitter-Taste[4]

https://pdfs.semanticscholar.org/bdc4/5fb9494878d82e9325553f5a6ec813871356.pdf [5]

http://extension.oregonstate.edu/gardening/cucumber-bitterness-explained

https://en.wikipedia.org/wiki/Cucumber