Bitter Fruits

[Clo-Trine]

Say you had two common bitter fruits; a lemon and a lime. Lets say you boil these fruits, would you lose the bitterness?

[theprof]

No you would not. the bitterness would be diminished slightly following prolonged boiling, but it would be hardly perceptible.

Now before I go any further, someone will soon appear on here and tell both of us that lemon and lime are sour NOT bitter. Whilst this indeed the normal perception of the fruit, it depends on such things as whether we're discussing the fruit as a whole, the juice, and even the zest of the fruit and/or it's mesocarp. Try blending an entire fruit in a food processor and taste the outcome.

Bitterness in citrus fruits is predominantly due to compounds called limonoids, around which 35 have been identified. Almost all limonoids are very bitter and are a type of compound called triterpinoids, all of which are insoluble in water. You simply cannot boil them out of fruit.

The peel of lemons and limes contain a limonoid called limonene, which gives the fruit their distinctive odour when combined with other non-limonoids such as citronellal and various terpineols. However, the white mesocarp of the fruit, contain a related limonoid compound called limonin, which is bitter along with other bitter non-limonoids such as coumarin and flavone glucosides.

(continued)

[theprof]

However, that�s not the whole story. Some of the limonin contained in the fruit combine chemically with glucose molecules present in the fruit to form compounds called limonoid glucosides, all of which are non-bitter in taste. The older the fruit, the more of these limonoid glucosides accumulate in the central tissues of the fruit.

This is why the lemons and limes you buy in supermarkets are fairly immature fruits; more mature specimens would be sweeter.

Incidentally, the properties of these compounds is utilised commercially and by home cooks each year when making Seville orange marmalade. The bitterness from the limonoids contained in the orange peel is not neutralised even by prolonged boiling.

[Ice.Maiden]

Oh LOL!!!! A somewhat long-winded answer, theprof - but correct!

[theprof]

Long-winded? It depends on your point of view Ice.Maiden. As a university professor, I do try to base my answer on the likely knowledge of the questioner, but sometimes too simplistic an answer only leads to further questions. that's why a compromise is often called for.

In this case, there are fourteen known compounds that impart the distinctive odour to lemon peel and eleven to lime peel. Little purpose would be served by listing them all. Likewise, discussion of enantiomers, which are also relevant would be pointless.

So where does concise end and long-winded begin Ice.Maiden? Yes, sometimes I get it wrong, but as I get invited to discuss scientific topics to people from aged 9 to 90, I like to think I'm able to gauge the understanding of the questioner.

Anyhow, I'm glad my answer meets with your approval.

[Clo-Trine]

Wow thank you, very informative!

[EdgarBratton]

Yes, it will.

[vanessartruex]

No, it will not loose its bitterness or sourness.

[leonmetheridge]

I think no we can't loose its bitterness.

[robertpbermudez]

No, the bitterness will not get dissolved with water. It will remain as it is, but only the outer cover of the lemon will get soften.