Several people on the question-and-answer types of forums have been asking about what lemon juice is made of, but most of the time they’re not really getting any useful answers. Many of the respondents are saying things like, “juice squeezed out of a lemon” without saying what the actual ingredients are or what kinds of chemicals are in there. So earlier today I decided to dig a little deeper and see if I could find out some more specific answers about lemon juice composition.
As with almost any types of juices derived from plants, lemon juice is actually mostly water. The next most important ingredient is citric acid, which comprises about 5 percent of the volume and gives lemon juice its characteristic tartness. Next is malic acid (approximately 7 percent of the total acid composition), ascorbic acid (vitamin C, used to prevent scurvy), and finally trace amounts of tartaric acid, fumaric acid, and several others. Lemon juice also contains minor amounts of glucose and other sugars.
Bottled lemon juice, often reconstituted from concentrate, contains all of the above ingredients but also has a few chemical preservatives added to help it maintain color and freshness because it is usually stored for long periods of time and may be shipped for long distances. These include sodium bisulfate, sodium benzoate, sodium sulfite, and lemon oil (usually extracted from the peel prior to juicing).
What is lemon juice made of in terms of nutrition?
In terms of nutritional value, lemon juice is best known for containing significant amounts of vitamin C (13% of the recommended daily allowance per fluid ounce) but also contains minor amounts of thiamin, magnesium, folate, and vitamin B6. Its calorie count is almost negligible at only 6.4 per ounce. Fat content is practically nil (less than 0.1 gram). Finally, lemon juice contains about two grams of total carbohydrates per ounce, along with 6 milligrams of sodium, 31 mg of potassium, and only 0.12 grams of protein.