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Canning -- Miscellaneous

Do you have any information about acidifying agents that are used in food preservation?

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Yes. Fruit Fresh prevents fruit from browning and losing flavor. It can be used when canning, freezing, drying, and serving fresh sliced fruit. It does not reduce the pH of a product and should not be used to acidify home canned foods. Fruit Fresh contains the following ingredients: dextrose (corn sugar), which is added as a filler; ascorbic acid (Vitamin C), which is an anti-browning compound; and silicon dioxide (free-flowing agent), which prevents the dry mixture from clumping. Ascorbic acid is not an acidulant - it does NOT alter the pH of a product. Ascorbic acid (Vitamin C) inhibits browning. To ensure safe acidity in tomatoes and figs, add two tablespoons of bottled lemon juice or 1/2-teaspoon of citric acid per quart of tomatoes. For pints, use one tablespoon bottled lemon juice or 1/4-teaspoon of citric acid. Instead of lemon juice or citric acid, you can use four tablespoons of 5 percent (50 grains) acidity vinegar per quart. However, vinegar may cause undesirable flavor changes. Lemon juice contains citric acid and vinegar contains acetic acid. These are both organic acids that can be used to alter the pH of a product. Therefore they are both recommended to acidify preserved foods. It is important to use bottled lemon juice rather than fresh lemon juice. Bottled lemon juice is standardized, so the amount of citric acid is known. The amount of citric acid is unknown in fresh squeezed lemon. Therefore, adding 2 tablespoons of freshly squeezed lemon juice to a product might not properly reduce the pH of the product.

PREPARED BY: Angela M. Fraser, Ph.D., Associate Professor/Food Safety Specialist, and Carolyn J. Lackey, Ph.D., R.D., L.D.N., Professor/Food and Nutrition Specialist, North Carolina State University. (August 2004)

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