How can I buy fresh and healthy vegetables?

Vegetables refer to plants (mostly herbs) other than grain, which can be cooked and cooked into food. Vegetables are one of the essential foods in people's daily diet. Vegetables can provide a variety of vitamins and minerals necessary for human body. According to the statistics of FAO 1990, 90% of vitamin C and 60% of vitamin A necessary for human body come from vegetables. In addition, there are many phytochemicals in vegetables, which are recognized as effective components beneficial to health, such as carotenoids, dipropylene compounds, methyl sulfur compounds and so on. At present, the nutrients in fruits and vegetables can effectively prevent chronic and degenerative diseases, and many substances are being discovered.

Vegetables are still living in storage, so it is necessary to resist the invasion of bad environment and pathogenic microorganisms, maintain quality, reduce losses and extend storage period. Therefore, it is necessary to maintain the normal life process of fresh vegetables during storage and minimize the changes in appearance, color, weight, hardness, taste and fragrance in order to achieve the purpose of preservation. Therefore, it is necessary to adopt corresponding preservation techniques according to the physiological changes of vegetables after harvest, so as to promote the healthy development of vegetable industry in China.

There are many kinds of vegetables, fruits and vegetables with different nutritional values. Generally speaking, it can be divided into two categories by color: dark green leafy vegetables, such as spinach and amaranth; These vegetables are rich in carotene, vitamin C, vitamin B2 and various minerals. Light-colored vegetables, such as Chinese cabbage and lettuce, are rich in vitamin C and low in carotene and minerals. Some vegetables are abnormal in color, so pay attention. For example, the leaves of vegetables have lost their usual green color and are dark green, and the green color of edamame is abnormal. They may have been sprayed or soaked with methamidophos pesticide before harvesting and are not suitable for purchase.