Abstract
Nitrate and nitrite contents of spinach were analyzed about three positions; a middle part of leaf blade, a middle part of petiole, and a basal part of petiole including stem. Their changes in contents and to nitrite during storage, without and with cooking, were observed in relation to film-packing methods and storage temperatures. Their contents in canned spinach for baby food were also analyzed.
1) Nitrate content varied markedly among individual plants and positions in a plant. The highest content was found in middle-petiole, and the lowest in basal petiole.
2) No change of nitrate and nitrite contents in raw spinach was found during storage, but rapid increase of nitrite occurred in slight-decayed materials which had been stored at 20°C for 10 days in sealed palyethylene bags.
3) In cooked spinach, nitrite was detected after 4 days in storage at 6°C, and nitrate decreased coincidently.
4) In canned spinach, the content of nitrate did not show any change at all tested storage-temperatures.
5) When the spinach was boiled in water for 3-10minutes, 55.7-73.5per cent of nitrate were removed in the water, and with subsequent washing for 10minutes more 9.7-16.5per cent were removed.
