The Effect of Blanching, Freezing and Freeze-Storage on Changes of Some Chemical Compounds Content in New Zealand Spinach

The aim of the work conducted in 2003-2004 was the estimation of the effect of blanching, freezing and freeze-storage on the content of chosen chemical compounds in plants of New Zealand spinach grown from seedlings. The determinations included dry matter, total protein, L-ascorbic acid, titrable acidity, total sugars, crude fibre, total ash, pH, nitrates, nitrites and chlorophyll content in the experimental material (fresh, blanched, frozen and stored shoots with leaves of New Zealand spinach). Used in the experiment procedures had a significant effect on changes of dry matter, total protein, L-ascorbic acid, titrable acidity, total sugars, crude fibre, total ash content and pH. After blanching their losses reached respectively: 34.9, 6.7, 70.2, 45.0, 56.3, 19.3, 52.9%, in relation to the raw material. However, the value of pH increased to 6.75. After freezing the losses, in relation to the blanched material, were: 21.7% for total protein, 21.4% - L-ascorbic acid, 27.3% - titrable acidity, 42.9% - total sugars, 4.5% - crude fibre, 2.5% - total ash, and pH decreased to 6.45. Frozen material was stored for 3, 6 and 9 months in a freezing chamber at -25 ÷ -27°C. The period of storage did not have statistically significant effect on the preservation of determined chemical components.