Vitamin C in fruits and vegetables
AbstractStrong opinion about reducing vitamin C content in traditional cultivars of fruits and vegetables as a result of intensive farming practices, on the one hand, and depletion of soil, waste of fertilizers, on the other hand, takes place. The aim of the study was to assess changes in vitamin C content in fresh vegetables, fruits and berries from the 40s of last century to the present. Available national and foreign data from official tables of the chemical composition tables published in different years, including the most typical values, based on the results conducted in a number of research institutes, laboratories and university departments, as well as some original investigations and unpublished own results were used to analyze possible changes of vitamin C content in fruits and vegetables. For comparison we take into consideration only results from the most common and affordable since the last century method of visual titration, which has a relative error of 20%. Analysis of vitamin C content conducted according 5–58 studies from the 40s of the last century to the present, for 32 types of greens and vegetables (potatoes, various types of cabbage and onion, garlic, carrot, turnip, tomato, pepper, eggplant, cucumber, squash, peas, turnip, garden radish, parsnip, rhubarb, parsley, dill, lettuce, onion, spinach, sorrel), and according to 6–50 studies of 24 sorts of fruits (apple, pear, mandarin, orange, lemon, grapefruit, pineapple, banana, watermelon, cantaloupe, grapes, peach, apricot, plum, cherry, blackberry, blueberry, strawberry, raspberry, blackberry, gooseberry, black currant, red and white) has been done. It was found that the average content of vitamin varies slightly. Deviations from the average for all the years of research do not exceed the standard deviation. Analysis of longitudinal data did not confirm a vitamin C decrease. This means that vitamin value C of fruits and vegetables remains approximately constant, due to the successful selection of new varieties with increased vitamin value. Thus, the view of reducing the C-vitamin value in cultivars produce proved unfounded.
Keywords:vitamin C, change of vitamin C value, fresh vegetables, fresh fruits, fresh berries