| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1990: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1989: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Research Abstract |
Recently the application of high pressure treatment to processing and storage of foods has been gaining a significant interest, but its effect on lipid oxidation has been elucidated to a lesser extent.
In this study, the model system consisting of defatted sardine meat and sardine lipids (20 %, W/W) was prepared and pressurized at 500, 1000, 1800 atm for 30 and 60 min (at room temperature), respectively. After high pressure treatment, each model system (2 g) was placed in 100 ml flask and stored at 5^ﾟC in the dark for up to 4 days. The extent of sardine lipid oxidation was determined every day by using such oxidation indices as POV, TBA, oxygen absorption, UV absorption, and developments of brown color and fluorescence. It was revealed that the oxidation of sardine lipids during storage was accelerated by the pressure treatment and its extent was relative to intensity and duration of the treatment.
Another model system prepared with sardine meat washed once or three times by cold water
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was treated at 1800 atm for 60 min. The rate of sardine lipid oxidation decreased by repetition of washing treatment and was fairly related to the amount of total and heme irons of sardine meat. However, high pressure treatment also caused the acceleration of lipid oxidation in any of model systems.
In next experiments, the water content of the model system was altered (7, 17, 24, and 35 %) and pressurized at 1800 atm for 60 min. Water activities of those systems were 0.65, 0.86, 0.92, 0.97, respectively. The oxidation rates of sardine lipids were 7 %> 35 %> 24 %> 17 %. At 17 and 24 % water contents, lipid oxidation proceeded only to some extent during storage of 4 days. On the other hand, at higher water contents (more than 17 % in this study) the oxidation rate of saudine lipids in the pressurized model was slower than that in the unpressurized system.
Oxidation of sardine lipids in the pressurized model systems was effectively prevented by the addition of alphaーtocopherol (0.2 %) during storage at 5^ﾟC for 28 days. Less
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