1. There are some difficulties on the tomato manufacturing in Japan ana especially discolouration caused by manufacturing treatment may be mortal as tomato products.
To be assumed that this fault is due to varietal characters of raw material tomatoes, in this experiment common varieties were given up and Italian tomatoes were adopted.
On six strains of Itahan tomatoes, the colour properties were studied.
2. Each puree (S.G. = 1.040) manufactred by vacuum concentration from these Italian tomatoes had retained brilliant colour and their λ_d (dominant wave length) were about 610mμ respectively.
3. Used-above puree canned tomato sardine was manufactured. Though it was sterilized long time in high temperature, every puree had not been discoloured so much.
4. As the whole, there was little difference among Italian tomatoes employed in so far as the colour property and their natural colour was keeped satisfactorily all the time through manufacturing process.