Lemonade can not be drunk during the day, will turn black?

[Lemonade can not be drunk during the day, it will turn black?】 There are anecdotal rumors: lemons are photosensitive food, easy to absorb light, lemonade will be blackened during the day. First of all, lemon itself is indeed a kind of photosensitive food, because the limonene and coumarins contained in lemons are very sensitive to light sources, and when they come into contact with light sources, they will act, resulting in blackening. However, lemons contain extremely small amounts of photosensitive substances such as limonene and coumarin, and the content of limonene in lemon water where people put a few pieces of lemon is extremely low, which is one of them; second, limonene and coumarin are fat-soluble substances, almost insoluble in water, mainly in lemon essential oil, lemonade can hardly be soaked; moreover, even if it can be ingested into the body, it is necessary to have enough daylight exposure to make the skin dark. In fact, it is mainly exposed to the sun, and photosensitive substances such as limonene will also be tanned without ingestion. Therefore, lemonade can not be drunk during the day without any scientific basis. (via Popular Science China)

Source: Guangdong 12320