| Popis: |
In making use of the ultraviolet rays as an antirachitic activating agent, it is necessary, of course, to consider harmful or destructive effects which may be produced simultaneously as the food materials are exposed. It is well known that protein substances become coagulated, that enzymes are destroyed and that even starches acquire a very distinctive taste upon long exposure. Zilva (1) showed that vitamia C in decitrated lemon juice was not destroyed by exposure to the radiations of a quartz mercury vapor lamp for six to eight hours; vitamin B in autolyzed yeast, after being exposed for six hours, apparently was not destroyed, but vitamin A in butter showed itself to be much more labile to this treatment, because after an exposure of eight hours, the butter fat, fed at a level of 2 per cent did not prevent the incidence of ophthalmia in rats. Spinka (2) reported that ultraviolet light did not destroy vitamin B in yeast nor vitamin C in lemon juice, but treated butter fat was found toxic unless air was excluded. Zflva (3) reported that the death of Spinka's mice possibly was not due to toxicity but to destruction of vitamiu A. These deductions were based upon Zilva's experience with rats in his previous paper (1). Later Zilva (4) showed that this destruction was due to ozone generated during the course of radiation. When the radiation was carried out in C02 vitamin A was not destroyed. Peacock (5) and Holmes and Pigott (6) also referred to vitamin A destruction by ultra violet. Titus, Hughes, Henshaw, and Fitch (7) showed that in the irradiation of mill~; vitA.rn~n A con |
