The effect of fridge storing, cooking and freezing on the nitrate and nitrite contents of spinach.

The aim of this study was to determine the nitrite and nitrate content of spinach samples (n=24). Spinach samples were washed, either stored in refrigerator (aerobic and anaerobic condition), cooked (without water, with water or pre-boiling) or stored in freezer (18 °C, 6 months). The nitrite and nitrate content of spinach was measured by spectrophotometer. Results showed that a low amount of nitrate reduced after washing since nitrate is water soluble (P>0.05). Cooked without water increased the nitrate levels (P>0.05) whereas cooking in water reduced (P 0.05). Both cooked without water (P>0.05) and cooking in water (P 0.05). There was no change in the amounts of nitrate and nitrite in vegetables during freeze storing.