Abstract
Using the rat growth method with the system of controls and precautions developed by Dr. Edgeworth, Dr. Spohn and the authors, studies were made of the percentage destruction of vitamin B at the temperatures 100°, 110°, 120°, 130° C when in each case the heating was continued for 4 hours and the vitamin was contained in a water solution (tomato juice) at the natural acidity of the tomato juice, namely pH = 4.3.
The juice of canned tomatoes was chosen as a suitable form in which to study vitamin B and for the further reason that the results here obtained would thus become directly comparable with the results of the studies, previously made in our laboratory, upon the heat destruction of vitamin C.
For descriptions of methods and for experimental data and their discussion, reference must be made to the original papers in the Journal of the American Chemical Society. 1 In the paper of which the present communication is an abstract the effects of different amounts of vitamin B upon the weight curve of the young rat are shown quantitatively and the percentage of vitamin destroyed by heat at each temperature is computed from the experimental determination of the quantity of heated juice which shows the same vitamin value as a given standard quantity (usually 4 cc. per rat per day) of the unheated juice. It is also explained that the percentage destruction computed from the experimental data may differ slightly according as we accept as coincident those results which approximate each other within close limits of experimental error (method A) or “correct” such results by computing what change in the quantities of juices fed would have brought the final points of the weight curves into exact theoretical coincidence (method B). These two methods of interpreting the experimental data yield respectively the following results:
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