Green vegetables are an indispensable component in a healthy diet. From spinach, broccoli, lettuce to beans, vegetables provide abundant vitamins, minerals, fiber and antioxidants, contributing to supporting the immune system, digestive system, cardiovascular system and overall health. However, many people wonder whether storing green vegetables for a long time will reduce their nutritional value.
According to Ms. Edwina Raj, Head of Clinical Nutrition and Diet Service at Aster CMI Hospital (Bangalore, India), the freshness of vegetables directly affects nutritional value. After harvesting, natural biological reactions in vegetables continue, making enzymes continue to function and causing part of the nutrients to decompose over time. This situation occurs faster when vegetables are not properly preserved or left for too long.
Among nutrients, vitamin C is the most easily lost component. This is a water-soluble vitamin, very sensitive to air, light and temperature. Green leafy vegetables such as spinach and lettuce can lose a significant amount of vitamin C after only a few days of storage, even when stored in the refrigerator. In addition, folate and some antioxidants also gradually decrease over time.
The three main factors that cause green vegetables to lose nutrients quickly are exposure to air, light and temperature. When vegetables come into contact with air, oxidation occurs, causing vitamins to decompose. Light, especially harmful to green leafy vegetables, also contributes to reducing nutrient content. In addition, unstable temperatures, including minor changes, can accelerate the decline in nutritional value if vegetables are stored for a long time.
Freezing helps slow down the enzyme breakdown process, thereby prolonging the freshness of vegetables. However, this method cannot completely prevent vitamin deficiency. Conversely, proper freezing can help retain most of the nutritional value, especially when vegetables are freeze immediately after harvest. However, the vitamin content can still be reduced if the storage time is too long or the vegetables are thawed and then frozen again many times.
To limit nutrient loss, experts recommend storing vegetables in a sealed box or vacuum bag, placed in the refrigerator compartment and avoid washing vegetables before storage because humidity makes them spoil quickly. Vegetables should only be washed immediately before processing or eating.
According to Ms. Edwina, vegetables left for a long time are not necessarily unsafe if there are no signs of mold, viscosity or strange odors. However, in terms of nutrition, they no longer bring the same benefits as fresh vegetables. Therefore, to maximize nutritional value, consumers should buy just enough vegetables and use them within a few days after buying.
