Abstract: In order to understand the effects of Maillard reaction intermediates on the flavor and color quality of sugar-substituted breads, the prepared intermediates from the Maillard reaction between fructose and proline were added to three kinds of sugar-substituted breads (made with xylitol, allulose, and mogroside, respectively), which were determined for color and browning degree using an ultraviolet spectrophotometer and a colorimeter, respectively. Besides, the volatile components were analyzed qualitatively and quantitatively by headspace solid-phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC-MS). Finally, quality evaluation was carried out based on consumer liking scores. The results showed that the Maillard reaction intermediates improved the flavor quality of different sugar-substituted breads to a certain extent, promoting browning reaction and significantly enhancing the color of the sugar-substituted breads, resulting in a yellow-brown crust. Meanwhile, the addition of the intermediates increased the types and contents of volatile compounds in the sugar-substituted breads, with a significant increase being observed in the contents of baked flavor-active compounds produced by the Maillard reaction such as pyrazine and pyridine as well as some aldehydes and ketones. The results of sensory evaluation indicated that the Maillard reaction intermediates enhanced the preference and acceptability of consumers towards sugar-substituted breads. The results of this study demonstrated that the intermediates of the fructose-proline Maillard reaction were effective in improving the flavor and color quality of sugar-substituted breads, which provides theoretical support for the application of the Maillard reaction intermediates in bakery foods.

Key words: sugar-substituted bread; Maillard reaction intermediates; non-enzymatic browning; headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry; volatile organic compounds