Rich in water (93 to 95%), tomato contains only small amounts of energy elements (about 3% carbohydrate, less than 1% protein, trace fat). Thus, it provides little more than 15 kcal per 100 g or 63 kJ.
Its carbohydrates (or carbohydrate) are represented mainly by fructose and glucose, sugars rapid assimilation, and small fractions of rare sugars, such as pentosans or hexosans.
Its natural organic acids (mostly citric acid and malic acid) give it its flavor slightly tart. The rate of these organic acids tend to decrease during maturation, together with the amounts of carbohydrates. Thus, for early and late tomatoes, the sugar / acid ratio rarely exceeds 7, while for full-season tomatoes and perfectly ripe (in August or September), it reaches 10: the tomatoes are so sweet and “fruity “.
The fibers of the tomato (mainly cellulose and hemicellulose, pectin and some traces) are averaging 1.2 g per 100 g, concentrated in the skin and seeds.
Among the minerals of the tomato, potassium dominates (accounting for nearly half of the total!). Are also quite abundant chlorine (51 mg/100 g), phosphorus (24 mg/100 g) and magnesium (11 mg/100 g).
Note that depending on the type of soil and fertilizer used, the mineral content can vary widely, and go from simple to double or treble or more (for chlorine or sodium, for example). Minerals combine with organic acids to give the residue alkaline quality (basic). Thus, despite its sour taste, the tomato helps maintain a good acid-base balance by promoting the alkalinization of the internal environment.
Trace elements are numerous but there may be significant levels of iron and zinc, and traces of cobalt, nickel, fluorine, boron, selenium …
All water soluble vitamins are well represented in the tomato, beginning with vitamin C, the rate can vary from 10 to 30 mg (10 to 20 mg in most cases). The maximum levels (20 mg and more) are found in field-grown tomatoes in season. This is a significant contribution, since the daily requirement of vitamin C in adults is 80 mg.
Provitamin A (or carotene) is a fraction of the red pigment in tomatoes (in association with lycopene, which has no action vitamin A). The content of provitamin A precursor of vitamin A, is about 0.6 mg per 100 g, but again, we can take on many different levels, depending on the varieties and degrees of maturity (0, 2 to 0.8 mg). In all cases, a tomato 100 g covers an appreciable fraction of the daily intake recommended by provitamne A (3-5 mg).
The B vitamins are numerous and relatively abundant, all are represented, including biotin (vitamin B8) and folic acid (vitamin B9).