食品加工

Since some possibility of application of ozonation in processing or storage of foods has been developed, change of food constituents should be preliminary discussed, owing to high oxidizing ability of ozone. At first, variation of nucleic acids after ozonation was examined, in connection with its bacteriostatic action. An absorption spectrum of DNA solution was changed by ozonation depending on pH of DNA solution. At pH 5, the optical density between 240 mμ and 300 mμ was decreased, the highest one being at 260mμ. On the other hand, while the optical density was similary decreased, it was increased at a range of shorter wave length below 240 mμ. On the contrary, the optical density was increased at shorter range below about 275 mμ at pH 9. In this case, highr increase was observed at shorter wave length. However, relative viscosity of DNA solution was decreased by ozonation with about the same rate at pH 5 and 7, but a little lower one at pH 9. Then, base composition of DNA was also examined after ozonation. At pH 5 and 7, bases were decomposed in the following order, thymine, guanine and cytosine, and only adenine was maintained, whereas, at pH 9, 4 bases were detected under the same condition of the treatment. An absorption spectrum of RNA solution was also changed and some difference was observed in variation of the spectra of both DNA and RNA. The optical density was decreased at pH 5, but increased at pH 7 with minimum rate at 270 mμ. However, it was increased at pH 9 similar to DNA. On the other hand, bases in RNA were degraded in the following rate of guanine, cytosine or uracil, and adenine. The result indicates that adenine in nucleic acids is the most stable against ozone.