Broccoli turns yellow because it can't turn green without light and chlorophyll, so it is yellow. Also because it is not fresh, the rape just bought is bright in color, and it will turn yellow in a few days, which means it will get old. If there is no deterioration, it will not affect eating if it turns yellow slightly.
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Nutritional value:
Among all kinds of vegetables, which one has the highest nutritional value? You may find it difficult to compare. However, a recent study in Japan concluded that the average nutritional value and disease prevention effect of broccoli far exceeded that of other vegetables.
Broccoli is rich in nutrients, including protein, carbohydrates, fats, minerals, vitamin C and carotene. In addition, the mineral composition of broccoli is more comprehensive than other vegetables, and the content of calcium, phosphorus, iron, potassium, zinc and manganese is very rich, which is much higher than that of cruciferous cabbage.
Baidu encyclopedia-broccoli