pleasei need an exact and scientific explanation how rubbing removes bitterness in cucumber?

Answer 1

The answer is yes , it does remove.

YOU NEED NOT ACTUALLY RUB IT AGAINST ANY THING.

ONLY CUTTING THE ENDS DO THE TRICK.

NOW READ FURTHER-


net search-1) THE OCCURRENCE OF BITTERNESS IN CUCUMBER (CUCUMIS SATIVUS L. CV.KAGAFUTOKYURI) IN RELATION TO NITROGEN LEVELS
Author: Y. Kano
Keywords: Cucumber, Cucumis sativus L., bitterness, nitrogen levels
Abstract:
For the production of high qyuality cucumber Cucumis sativus L. cv. Kagafutokyuri, differences in nitrogen levels in the leaves between a non-bitter line and a bitter line, and in the leaf and fruit between the bitter ones and the non-bitter ones were compared.
The percentage of bitter fruit was higher in the bitter line than in the non-bitter line. Vegetative growth was more vigorous in the former than in the latter. The total leaf nitrogen and amino acid nitrogen levels were higher in the bitter line than in the non-bitter line, but the nitrate ion level was lower in the former in the latter.

The leaves on the upper nodal position were more bitter than those on the lower one.

The degree of bitterness of the leaf or fruit corresponded to total-N and amino acid-N levels.

We concluded from these results that high total-N and amino acid-N levels in the leaf induce bitterness in leaves and fruits by promoting nitrogen metabolism, which in turn favors the enzymatic synthesis of cucurbitacin C, the bitter factor.

2) From University of Nebraska-- All cucurbits produce a group of chemicals called cucurbitacins, which cause the vegetables to taste bitter, and the higher the concentration of cucurbitacin the more bitter the vegetable will taste.

In commercially cultivated cucumbers and zucchini, they are normally in such low concentrations that they cannot be tasted. These chemicals provide other attributes to the cucurbits, such as the musky scent of cantaloupe.

Mild bitterness is fairly common in cucumbers resulting from higher levels of cucurbitacin triggered by environmental stress, like high temperatures, wide temperature swings or too little water.
Uneven watering practices (too wet followed by too dry), low soil fertility and low soil pH are also possible stress factors. Over mature or improperly stored cucurbits may also develop a mild bitterness, which is often not severe enough to prevent gardeners from eating them.

3) From one Recipe--

Q: My grandmother used to cut the ends off the cucumber and rub them together to draw out the bitter juices. What's up with this?

A: It is an old wives' tale. Really. Try it with 100 cucumbers and not on another 100 if you don't believe me.

Some cucumbers can be bitter, especially at the ends, and you might want to cut off the ends because of this.

In particular, cut off the blossom end of fresh cucumbers, as the blossoms contain enzymes that are bitter and others that cause excessive softening of pickles.

You can draw out the bitterness in the rest of the cucumber by slicing, salting, and draining it before adding to a salad.

This works on the principle of osmosis. The principle of bitterness spontaneously leaving the cucumber because you rubbed the end... well, it does no harm, so do it if you want.

My addition- The chemical that disappears is cucurbitacin, the villain! when you rub it the cut portion is EXPOSED and that brings about the change.


I think you got your answer.

Answer 2

Sugar!