Cooking Tip Thursdays is dedicated to making time in the kitchen quicker, easier, and just plain better….
Oxidation is a destructive process, for the cells of our bodies and for the structure of our food. Oxidation of fats and oils leads to rancidity, while oxidation of fruits and vegetables causes discoloration – usually a browning or darkening of the flesh. When you cut into a fruit or vegetable the cells are severed, this causes a release of enzymes that when exposed to oxygen in the air create a change in chemical composition. This change in chemical composition is the oxidation reaction.
Preventing oxidation and discoloration before canning, freezing or placing in a serving bowl ensures your produce looks as good as it tastes. Some of the fruits that turn brown are avocados, apples, pears, peaches, and bananas. Some of the vegetables that turn brown are potatoes, sweet potatoes, parsnips, celeriac and trimmed artichokes. Although fruits and vegetables that are discolored due to oxidation are still perfectly edible, you can stop oxidation using the following simple methods.
- Citrus Juice: Prevent browning by brushing the surface of the fruit/vegetable directly with lemon juice. Other citrus fruits, such as limes, oranges, and grapefruits, work as well.
- Soak in Acidulated Water: Place the cut fruit/vegetable in a water mixture that has been made acidic by combining lemon juice, lime juice, vinegar or white wine with water. The squeezed fruit can also be cut into slices and added to help acidulate the water. Acidulated water can be made by adding 1-1/2 tablespoons of vinegar, or 3 tablespoons of lemon/lime juice , or 1/2 cup of white wine, to one quart of water. Do not over soak fruit, apples shouldn’t soak for more than 15 minutes and bananas for no more than 3 to 5 minutes. Drain and pat fruit/vegetables dry before using. This is the method I use the most, especially for trimmed artichokes, sliced pears, and apples.
- Vitamin C: Dipping fruit into a solution of crushed Vitamin C tablets and water can prevent oxidation. This is because the vitamin is an antioxidant, which protects the cells of the fruit from free radicals, which cause them to age (the same goes for our skin – which is why it’s so important to include antioxidants in your diet). Cut the fruit/vegetables into slices first so the liquid penetrates the cells adequately.
- Ascorbic Acid: Sold as a commercial product, this can be added to water to create an anti-browning solution. Ascorbic acid is a natural property in many citrus fruits, such as oranges and lemons. … it is literally just Vitamin C.
- Apple Juice For Apples: Soak apples slices in apple juice until ready to use. The acidity in the apple juice prevents the apple slices from browning and doesn’t change the flavor of the apple.
- Cold Water For Potatoes: When the potato is completely peeled, place it in ice cold water immediately until ready to cook or ready to cut to desired size. The cold water will prevent the outer surface of the potato from discoloring.
- For Vegetables: Cook the vegetables immediately to deactivate the enzyme. This will stop the reaction from happening and turning the vegetable brown.
- For Avocados: Plastic wrap pressed tightly against the surface of the avocado will create a barrier against the air.
- For Pesto: Using a little lemon juice helps to keep pesto from turning brown, the lemon will keep the basil from oxidizing.