Tomatoes of two cultivars, Kozu and Yozu, at breaker stage were irradiated with Co⁶⁰ gamma rays at 250, 500 and 1000 Krad at the rate of 250 Krad/hour. The fruits were held at 20°C during irradiation and storage. The pattern of climacteric in respiration showed that the irradiation (250 Krad) would delay ripening about 2 days in comparison with unirradiated samples. The fruits irradiated at 1000 Krad did not exhibit the pattern of climacteric rise in respiration during storage and failed to ripen normally. The ethylene production of tomatoes increased immediately after irradiation. The rates of the production in the 250 Krad and 500 Krad fruits increased to peak at 2 days after irradiation and declined slowly thereafter, while the initial increase at the dose of 1000 Krad was temporary and the fruits exhibited a much lower, rate of ethylene production during storage. The pigmentation and ethylene production of the irradiated fruits (250 Krad, 500 Krad) were slightly accelerated with 100 ppm and 500 ppm ethylene treatment. The ethylene production by tissue slices of the unirradiated and 250 Krad-fruits was enhanced by the addition of H₂O₂, glycolate, oxalate, L-methionine, L-methionine+H₂O₂ and citrate+H₂O₂, but that by the tissue slices of the 1000 Krad-fruits was much lower. When the phosphate buffer extract from the fruits irradiated at 1000 Krad was added to the slices of the unirradiated and 250 Krad-fruits, the ethylene production increased.

View full abstract

Changes of contents of phospholipids (PL) and their fatty acid composition in tomato fruits, cultured in the open were investigated during ripening and storage periods.
I) Total amount of PL appeared to increase during the early stage of maturation. When fruits were harvested at breaker stage and stored at 20°C, PL contents Showed remarkable decrease 4-5 days after harvest, corresponding to the time of climacteric peak of respiration, then was followed by gradual decrease.
II) Phospholipids were separated with thin layer chromatography and determined with Fiske and Subbarow's method. The phosphatidyl choline (PC) and phosphatidyl ethanolamine (PE) were found as the major constituents showing 60% of the total PL. The PC showed the same tendency as the change of total PL during the ripening and the storage. The PE content decreased 4-5day after harvest and after that tended to increase. Other compositions did not show marked change.
III) The fatty acid composition of total PL, PC, PE, ph. inositol and cardiolipid were analyzed with gas-liquid chromatography. Oleic acid (C_18:1), linoleic acid (C_18:2), linolenic acid (C_18:3) and palmitic acid (C_16:0) were determined as the main fatty acids of the PL and, as a whole, saturated fatty acid increased with progress of storage period. It appeared that higher unsaturated fatty acids, such as C_18:3, C_18:2, C_18:1, were metabolised rapidly during the first part of storage period.

View full abstract

Broad line NMR and high resolution NMR signals of water proton contained in fresh and dehydrated fish muscle were observed. The broad line NMR signal did not give the detail physical states of water.
The line width of fresh muscle under high resolution NMR spectroscopy was 3cps, which differs from that of pure water. Water proton in fish muscle gives a much broader and unsymmetric sygnal in progress of dehydration.
The meaning of these finding will be explained by further researches however, the results demonstrate that the water in fish muscle is a possible heterogenity.

View full abstract