Do tomatoes lose their nutritional value when they are made into tomato sauce? What about canned tomato sauce?

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    This question is borderline off-topic/unanswerable. First, which substances do you include under "nutritional value"? Second, which method of sauce preparation? If you are interested in the reduction of specific substances, please edit them into the question body and also specify the method. If you simply want to know if cooked tomatoes are less healthy than raw, then this question is off topic, see cooking.stackexchange.com/help/on-topic
    – rumtscho
    Jun 19, 2013 at 16:04

1 Answer 1


Nutritional changes in cooking foods (including tomatoes) are not simple to answer: cooking can reduce some nutrients, and it can make other ingredients more available.

Tomatoes are a case in point, as cooking has both effects. According to as study in the Journal of Food and Agriculture, as reported in Cornell Chronical, both effects happen. Vitamin C is reduced as it breaks down under heat, but certain lycoenes and anti-oxidants increased.

Tomato samples were heated to 88 degrees Celsius (190.4 degrees Fahrenheit) for two minutes, a quarter-hour and a half-hour. Consistent with previous studies, vitamin C content decreased by 10, 15 and 29 percent, respectively, when compared to raw, uncooked tomatoes. However, the research revealed that the beneficial trans-lycopene content of the cooked tomatoes increased by 54, 171 and 164 percent, respectively. Levels of cis -lycopene (which the body easily absorbs) rose by 6, 17 and 35 percent, respectively; and antioxidant levels in the heated tomatoes increased by 28, 34 and 62 percent, respectively.

See related: Does cooking in a pressure cooker destroy nutrients?