Molecular species and fatty acid distributions of triacylglycerols from germinating soybean cotyledons

Molecular species and fatty acid distributions of triacylglycerols obtained from cotyledons of soybean seedlings were investigated. Changes observed in triacylglycerol content were closely related to levels of total lipids present in the cotyledons. At day 12 of seedling growth, ca. 85% of triacylglycerols had been consumed. Immediately after the beginning of imbibition the oil consisted of triacylglycerols with even carbon numbers (from C‐50 to C‐60) based on the combined length of the fatty acyl chains present in a triacylglycerol. The dominant components throughout germination were C‐52 and C‐54 triacylglycerols. Fourteen molecular species of triacylglycerols were identified in the cotyledons. As soybean seedlings grew, the percentages of triacylglycerols decreased to 0.9–36.2% during the 12 days. Triacylglycerols containing one or more saturated fatty acids were hydrolyzed slightly faster than other species. Unsaturated fatty acids were dominant in the 2‐position throughout germination. These results suggest the mechanism of initial triacylglycerol hydrolysis may be different in various molecular species.