Effects of smoking on lipid oxidation in niboshi [boiled and dried anchovy Engraulis japonica] and niboshi powder

Effects of smoking on the lipid oxidation of niboshi, boiled and dried anchovy Engraulis japonica, and its powder during drying and storage were investigated. Boiled anchovy was smoked for 30, 60, and 360 min at 40-65°C, and then dried by air at 25°C. Total times of smoking and air-drying was adjusted to 30h. During the drying process, peroxide values (POV) of lipids in the samples increased with decrease in percentage of remaining highly unsaturated fatty acid (HUFA) depending on smoking times. Oxidized acid contents of lipids in the samples, which were accepted with a good indication of rusting developed on niboshi, increased during drying. In-creasing rates of oxidized acid contents in non-smoked control and the sample smoked for 30 min were higher than those of samples smoked for 60 or 360 min. Similar protective effects of smoking to lipid oxidation in niboshi were found during storage. Niboshi powder was also effectively protected from lipid oxidation by smoking although the lipid oxidation proceeded faster than that in the intact niboshi. These results indicate that smoking for 60 min is effective in protecting lipid oxidation of niboshi during the drying and storage processes, and at least 360 min is necessary for niboshi powder to protect the lipids from oxidation.