Abstract: In order to understand the effect of the Maillard reaction intermediates on the flavor and color quality of sugar substitute breads, the prepared fructose-proline Maillard reaction intermediates were added to three kinds of sugar-substituted breads (xylitol, allulose, and mogroside breads), and the indexes of the color and browning degree were determined by ultraviolet spectrophotometer and colorimeter, respectively. The volatile components were also analyzed qualitatively and quantitatively by using headspace solid-phase microextraction-gas chromatography-mass spectrometry, and finally the effect of the Maillard reaction intermediates in improving the flavor quality of sugar-substituted breads was evaluated in combination with the score of the hedonic test by consumers. The results showed that the fructose-proline Maillard reaction intermediates improved the flavor quality of different sugar-ubstituted breads to a certain extent. It promoted the browning reaction and significantly enhanced the color of the sugar substitute bread, resulting in a yellow-brown crust. Meanwhile, the addition of the intermediates increased the variety and content of volatile compounds in the sugar-substituted breads, among which the content of baking flavor compounds such as pyrazine, pyridine and some aldehydes and ketones were significantly increased through the Maillard reaction. The results of sensory evaluation also further indicated that the Maillard reaction intermediates could enhance the liking and acceptability of consumers towards sugar-substituted breads. The results of this study demonstrated that the fructose-proline Maillard reaction intermediate was effective in improving the flavor and color quality of sugar-substituted bread, which provides theoretical support for its application in bakery foods.

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