Identifying and characterizing the components related to the brown color of Chinese sugar-smoked chicken during processing

The desired color is a key indicator for consumer acceptability of Chinese sugar-smoked chicken. To investigate the formation of color attributes of Chinese sugar-smoked chicken during processing, color values, structural characteristics, and components of brown pigment were evaluated in 2 groups, which were defined as brown skin (BS) and normal skin (NS) of Chinese sugar-smoked chicken based on their color values. Compared with the NS samples, the BS samples showed significantly lower values of lightness, redness, and yellowness and higher content of malondialdehyde and 5-hydroxymethylfurfural. UV–visible and Fourier-transform infrared spectra suggested that the structure of brown pigment was similar to melanin. The brown pigment consisted of multiple chemical components including the polymer of fructose and glucose, and derivatives produced by lipid oxidation, which were identified by HPLC–tandem mass spectrometry. The polymer content of glucose and fructose, which was demonstrated as sucrose by HPLC analysis, was higher in the BS group than in the NS group. Our results indicated that the higher content of the polymer of glucose and fructose was mainly responsible for the brown color of Chinese sugar-smoked chicken.