Is citric acid the same as ascorbic acid?
Ascorbic Acid is C6H8O6
Citric Acid is C6H8O7
Bananas contain ascorbic acid but not citric acid. Citric acid is found in citrus fruits, such as oranges, lemons, limes, grapefruits, etc. See link below for more information. Better Answer: Yes. In fact, bananas contain much more citric acid than ascorbic acid (Vitamin C). A ripe banana contains 319 mg of citric acid -- that's 29 times the amount of the ascorbic acid in the banana! But the predominant organic acid in a banana is…
Ascorbic acid is present in tomatoes. Oxalic acid, though, is the main acid in tomatoes. Tomatoes contain citric, malic, oxalic, succinic, glycolic, tartaric, phosphoric, hydrochloric, sulphuric, fumaric, ascorbic, pyrrolidinonecarboxylic and galacturonic acids. The most abundant are citric and malic acids.
Covering the food with citric acid prevents browning because the acid reduced the pH below the optimum level for the enzyme (polyphenoloxidase) to catalyze the oxidative enzymatic browning reaction. Covering the food in ascorbic acid also prevents browning because ascorbic acid is an antioxidant which interferes with the browning reaction by preventing the intermediate products from being converted into melanins (the brown pigment).