菠蘿對口腔的刺痛感從何而來？
Where does the tingling sensation of pineapple come from?
菠蘿之所以會對口腔產(chǎn)生刺激，主要是因為菠蘿中含有的菠蘿蛋白酶（蛋白質(zhì)水解酶），可以切斷蛋白質(zhì)一級結(jié)構(gòu)當(dāng)中的肽鍵，使其水解為多肽。
The reason why pineapple can stimulate the mouth is mainly because the bromelain (proteolytic enzyme) contained in pineapple can cut off the peptide bonds in the primary structure of the protein and make it hydrolyzed into peptides.
吃菠蘿時，菠蘿蛋白酶就會破壞口腔黏膜的結(jié)構(gòu)，導(dǎo)致口腔、食道出現(xiàn)明顯的刺痛感、灼燒感，甚至?xí)?dǎo)致出血（與食用量有關(guān)）。

When eating pineapple, bromelain will destroy the structure of the oral mucosa, causing obvious tingling and burning sensation in the mouth and esophagus, and even bleeding (related to the amount of food).

鹽水浸泡可以殺滅菠蘿蛋白酶嗎？
Can salt water soaking kill bromelain?
從原理來看，酶的根本是蛋白質(zhì)，它由氨基酸構(gòu)成，本身擁有大量的羧基（—COOH）、氨基（—NH2）和羥基（—OH）等官能團。自然界中能使蛋白質(zhì)變性的因素（條件）主要有高溫、紫外線、強酸、強堿、重金屬鹽、甲醛、乙醇、苯酚等。
From the principle point of view, the root of enzyme is protein, which is composed of amino acids and has a large number of functional groups such as carboxyl (-COOH), amino (-NH2) and hydroxyl (-OH). The factors (conditions) that can denature proteins in nature mainly include high temperature, ultraviolet rays, strong acids, strong bases, heavy metal salts, formaldehyde, ethanol, phenol, etc.
食鹽的主要成分是氯化鈉（Nacl），它是一種鹽，但并不是重金屬鹽。
The main component of table salt is sodium chloride (Nacl), which is a kind of salt, but not a heavy metal salt.
氯化鈉當(dāng)中的鈉離子非常穩(wěn)定，幾乎不會發(fā)生任何化學(xué)變化，它沒有辦法像其他離子一樣與酶形成配位鍵，這樣一來也就不能影響酶的結(jié)構(gòu)形態(tài)（導(dǎo)致其不能和目標(biāo)反應(yīng)物結(jié)合，或是不能正常變性，或是替換掉酶中本來具有的金屬離子，致其失活）。

The sodium ions in sodium chloride are very stable and hardly undergo any chemical changes. It has no way to form coordination bonds with enzymes like other ions, so that it cannot affect the structure and morphology of the enzyme (resulting in its inability to react with the target). The substance binds, or cannot be denatured normally, or replaces the metal ions originally contained in the enzyme, causing it to inactivate).

為啥用鹽水泡菠蘿會好吃？
Why is pineapple soaked in salt water delicious?
雖然從原理上來看鹽水浸泡菠蘿不能使菠蘿蛋白酶變性失活，但用鹽水浸泡菠蘿同樣會有其他不可磨滅的“功勞”。

Although in principle, soaking pineapple in salt water cannot denature and inactivate bromelain, soaking pineapple in salt water also has other indelible "credit".

其一，使用鹽水泡菠蘿，對于很多人（相信鹽水可以讓菠蘿不扎嘴的人）而言，強大的心理暗示足以幫助大家起到止痛的作用，畢竟一次性吃不了太多菠蘿。
First, use salt water to soak pineapple. For many people (those who believe that salt water can keep the pineapple from sticking their mouths), strong psychological hints are enough to help them relieve pain. After all, you can't eat too much pineapple at one time.
其二，食鹽中的鈉離子是第一主族的陽離子，它本身具有抑制苦味的作用，所以鹽水浸泡之后的菠蘿必然會更加香甜。
Second, the sodium ions in table salt are the cations of the first main group, and it has the effect of inhibiting bitterness, so the pineapple after salt water soaking will inevitably be more fragrant and sweet.
因此，用鹽水浸泡菠蘿也可以讓菠蘿不那么“咬嘴”，增加美味的和諧度。

Therefore, soaking the pineapple in salt water can also make the pineapple less "bite" and increase the delicious harmony.

來源：科普中國（ID：Science_China）

Source: Popular Science China (ID: Science_China)