<p>Sesame oil is a common condiment in China, and the aroma of white sesame oil differs from that of black sesame oil. In order to investigate the reasons for this difference, the changes in the content of aroma precursors during the processing of sesame oil were analyzed. Changes in the composition and content of free amino acids, free sugars, hydrolysed amino acids and hydrolysed sugars before and after roasting were studied using white sesame seeds (WSS) and black sesame seeds (BSS). The results showed that the contents of basic and sulphur-containing amino acids changed significantly after sesame seeds were roasted at 200&#xa0;°C for 30&#xa0;min, and lysine, arginine and methionine were probably the most important aroma precursors. Free sugars in sesame seeds were mainly sucrose, followed by free glucose and free fructose. Glucose and fructose were the main hydrolysed sugars in sesame, followed by hydrolysed galactose and hydrolysed xylose. Glucose and fructose were probably the most important reducing monosaccharides affecting flavor and color during sesame roasting. PLS-DA analyses showed that there was a large difference between the amino acid and sugar contents of WSS and BSS, but the roasting treatment reduced this difference, and the effect of the difference on the amino acids was greater than the effect on the sugars. In this study, the composition and content changes of free and hydrolysed amino acids and sugars before and after roasting were analyzed from the point of view of Maillard reaction precursors, which provided important basic data for an in-depth investigation of the effect of roasting on Maillard reaction in sesame seeds, and could provide suggestions for the regulation of sesame oil flavor and production</p>