Oxidative stability of glyceroglycolipids containing polyunsaturated fatty acids.

The oxidative stability of glyceroglycolipids (GLs) from spinach or brown edible seaweed (Laminaria japonica) was compared with those of phosphatidylcholines (PCs) from salmon roe and triacyglycerols (TAGs) from soybean oil or sardine oil. All the lipids were subjected to autoxidation after removing oxidants and/or antioxidants such as chlorophylls, tocopherols, and carotenoids. The oxidative stability of the lipids decreased with increasing number of bisallylic positions in the molecule. Due to the higher mean number of bisallylic positions, salmon roe PC and sardine oil TAG were oxidized more rapidly than soybean oil TAG. Spinach GL and brown edible seaweed GL showed the same oxidative stability as that found in soybean oil TAG, although the mean number of bisallylic positions of both GLs was much higher than that of soybean oil TAG and approached the number found in sardine oil TAG and salmon roe PC. The present study indicates the important effect of galactosyl and sulfoquinovosyl moieties on the oxidative stability of GL.