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You can try adding citric acid (lemon juice) or vinegar to the washing water. It will help to preserve the color in a bit. You may also consider adding extracts of plants with antioxidant properties (eg rosemary, sage, thyme extract) to the washing water.

Many vegetables need to be washed before storage, and only washing is possible. Before use, water and moisture help to grow bacteria. Leafy vegetables, such as spinach and lettuce, should be kept in plastic bags and in the coldest area of ​​the refrigerator. The plastic bag creates a damp atmosphere and keeps the water naturally present in the vegetables. Vegetables such as carrots, beets and rapeseed can be kept for two weeks if they are placed in a plastic bag that is drilled in the refrigerator. The presence of some holes helps to change the air without losing much moisture. Cauliflower and broccoli can stay for five days in plastic bags inside the refrigerator. The cabbage remains for ten days, but it should not be washed or cut. Vegetables such as cucumbers and beans can also be kept in plastic bags for the inside of the refrigerator. Spices must be kept in paper bags in trays. Mushrooms should not be placed in plastic bags and should be kept in an open container and can be covered with tissue paper. Garlic and onions should be kept in cool places and away from moisture outside the refrigerator, prefer to suspend onions in the air, while preferably put garlic in dark places. Tomatoes can be kept for three or four days at the same temperature as the kitchen and away from direct sunlight. Tomato slices can be kept in closed plastic bags for two days in the refrigerator. It is best to peel and use the corn on the same day, but if you want to keep it, it can be kept for two or three days, but it should be cooled and cooled to cool, then placed in plastic bags inside the refrigerator.