1. Watermelon is a relatively sweet fruit

　　The sugar content of watermelon is 5.5% on average, and the sugar content of sweeter varieties can reach about 10% . This sugar content is less (or flat) than other common fruits, such as apples, pears, melons, grapes, etc., but the taste is often sweeter than other common fruits. This is because watermelon contains more fructose, accounting for about 60% of the total sugar (the rest is glucose and sucrose). The more common sugars in various fruits are fructose, sucrose and glucose. Among them, fructose is the sweetest, the sweetness is twice that of glucose, and 1.8 times that of sucrose.

　　2. Watermelon is sweeter after cold storage

　　The sweetness of fructose also has a significant characteristic, which is inversely proportional to the temperature, that is, the lower the temperature The higher the sweetness, the higher the temperature and the lower the sweetness. When the temperature is ≤10℃, the sweetness of fructose is the largest (1.8 times that of sucrose); as the temperature increases, the sweetness of fructose slowly decreases. When the temperature reaches 40℃, the sweetness of fructose and sucrose are the same; the temperature reaches 60 At ℃, the sweetness of fructose is lower than sucrose (0.8 times that of sucrose). According to this characteristic of fructose, watermelon will be sweeter when eaten in the refrigerator.

　　 For people with no gastrointestinal tract disease, eating iced watermelon is like harmless drinking ice water. There is no evidence that eating cold fruits and drinking ice water will increase the prevalence of gastrointestinal diseases such as gastritis and peptic ulcers. Saying that ice-cold watermelon is harmful in one way or another is purely disturbing. In fact, I eat iced watermelon almost every day now. The watermelon I bought is always put in the refrigerator to cool down and then taken out at night. This is true almost every summer, and no problems have been found so far. As for people who have a bad stomach or intestine and are particularly afraid of eating cold things, it is naturally another matter.

　　3. Diabetes can eat a small amount of watermelon

　　 Another characteristic of fructose is that after eating, the rate of raising blood sugar is slower than that of sucrose and glucose, that is The glycemic index (GI) is low. Assuming that the GI of glucose is 100, fructose is only 23, and sucrose is 65. However, it is quite surprising that the watermelon''s GI is not low at 72. Obviously more than other common fruits, such as apple GI is 36, pear is 36, peach is 28, banana is 52, grape is 43. Why is this? It may be related to the watermelon also contains more glucose (about 1/4 of the total sugar). Similar to it is honey. Among the sugars of honey, fructose accounts for about 1/2, glucose accounts for about 1/5~1/4, and the rest is sucrose. The GI of honey is 73, which is very close to watermelon. Of course, the high or low GI of a certain food is sometimes difficult to explain, but the actual test data does. In any case, under the premise that the total amount of sugar consumed is equal, the effect of eating watermelon to increase blood sugar after a meal is more intense. Therefore, people with diabetes should eat less watermelon (for example, 100 to 150 grams), and do not eat large pieces.

　　 4. One way to choose a good watermelon

　　How to choose a good watermelon that is crisp and sweet? There are many ways, as long as you buy it frequently, repeatedly It''s easy to grasp. I often use the following methods to choose watermelon (applicable to cut open watermelon), which is uncomfortable: look at the watermelon seeds of the cut surface. If the watermelon seeds are uniform in size and generally fuller and darker, there are no or rarely white melon seeds , This must be a good melon.