Posted on 11 Mar, 2019
Preserving Vitamins in Fruit & Vegetables
The essential vitamins found in foods, especially fruits and vegetables are readily affected by storage and cooking methods. Incorrect storage conditions and overcooking can reduce or destroy the vitamins. Reduce exposure to air, water and heat as they all attach the vitamins in food. Avoid exposure by cooking whole if possible or cutting into large pieces and cutting into smaller pieces after cooking. This limits surface exposure to the elements. Also, when cutting fruit and vegetables, use a sharp knife as opposed to a blunt knife as this reduces the number of cells damaged within the food in the cutting process and this allows the cells to retain their nutrients. A similar thing happens when a fruit or vegetables experience bruising. When buying fruit and vegetables, avoid bruising as this is a sign the food has been damaged, and the nutrients have been affected in that part of the food.
When preparing fruit and vegetables, wash quickly because if fruit and vegetables are left in water, the water-soluble vitamins will leach out into the water and the food becomes less nutrient dense. Leaching also occurs when foods are boiled or deep fat fried. The water-soluble vitamins (B and C) are released out into the hot water, and the fat-soluble vitamins (A, D, E and K) are released out into the hot oil in the deep fat fryer.
Fruits tend to be most beneficial when eaten raw. However, nutrients in certain vegetables e.g. spinach and mushrooms, become more available when heated. However, be careful not to overcook foods as this destroys nutrients. Sautéing is a good way of cooking vegetables; especially is the oil they are cooked in is used in the end dish e.g. stir fry.
The material cooking utensils are made from is also very important in nutrient retention in foods. Iron pots and pan readily destroy certain vitamins especially in unlined.
Dressing salads or vegetables with oil aids the absorption of fat-soluble vitamins in the body. Extra virgin olive oil is a good oil for this purpose as it is high in unsaturated fats and antioxidants.
Keeping fruits and vegetables cool i.e. in the fridge after purchase slows down enzymatic spoilage as it temporarily inactivates enzymes. Freezing fruit and vegetables also retains the nutrients within the food so it can be utilised later. Blanching the food first (boiling for a short period of time and then submerging the food in ice cold water to stop the cooking process) also helps retain nutrients and maintains the vivid colour of the food. In some cases, frozen fruit and vegetables can be more nutrient dense than fresh. This is because frozen foods are processed soon after harvest whereas fresh food may not be eaten for a few days after harvest because of transport and storage both before and after purchase.
It is a well-known fact that fruits and vegetables are very good for us. However, it is important we know how to treat them in order to get the optimum benefits from them.
This blog was written by Laura Murphy who is studying Nutrition, Food and Business Management in St.Angela’s College, Sligo.