Why is the watermelon ice sweeter? Fructose sweetness will increase with the temperature becoming lower sweet!

Heat wave hit the mask boring, this summer also out of what door, at home blowing air conditioning to eat watermelon, it is not fragrant? Go out for five minutes, sweat for two hours, and immediately be genuine.
if at this time can eat a mouthful of "fairy" ice watermelon, that feel simply not too cool! Wait, as "the masses of melons", do not know whether there is no discovery, watermelon in the ice after, eat will be sweeter.
Is this a psychological effect? Let's find out the answer! The original summer "life-giving god" watermelon, after the ice really will become sweet, not an illusion.
this is because watermelon contains a lot of fructose in the strange, fructose sweetness will change with the temperature, the lower the temperature, the sweeter the fructose will be higher.
fructose is divided into alpha-D-furan fructose, beta-D-furan fructose and beta-D-man fructose, with the temperature decrease, the tinted fructose will increase, the tinned type than furan-type sweetness, so the sweetness of watermelon after refrigeration will be greatly increased.
also should remind that watermelon cut open is easy to breed bacteria, so as long as cut open should be eliminated as soon as possible Oh.
Source: Science China.