VARIATIONS OF NITRATE AND NITRITE CONTENT S DURING STORAGE OF VEGETABLE PRODUCTS

In the course of short- or long-time storage of vegetable products cer tain physical and biochemical processes are taking place which influen ce the contents and mutual ratios of nitrates and nitrites. The rate o f these variations depends particularly on storage conditions, but the species and variety of the crop also play their role. An overview of the knowledge of nitrate and nitrite variations in vegetables and pota toes is presented. The risk of undesirable conversion of nitrates to n itrites is higher in the species in which they are intensively accumul ated (e.g. in leaf vegetables). In these cases the storage conditions should be stricter. The same applies to plant materials with the exces sive content of nitrates which has resulted from the consequences of g rowing conditions (nitrogen overfertilizing, light shortage, unsuitabl e temperature and moisture conditions, harvest date, etc.). The specie s which are less prone to nitrate accumulation can be stored in optimu m conditions for many months while the starting content of nitrates is regularly slightly decreasing without increase in nitrite content. Th e results acquired at various workplaces, for different species and va rieties of vegetables and potatoes are far from being doubtless, which documents the complexity of the problem. In general it is true that o nly healthy, undamaged and uncontaminated products can be stored witho ut risks of nitrite content increase. The growth of nitrite concentrat ions usually indicates the reduced biological, and also eating quality of the products.