Effects of different sodium nitrite content on small molecule metabolites, free fatty acids, and volatile compounds in Xuanwei ham

• The addition of NaNO 2 increased a* values and decreased POV and TBARS values. • With 90 mg/kg NaNO 2 , nitrite residues were within an acceptable range. • NaNO 2 reduced the content of SFA and PUFA while increasing the content of MUFA. • NaNO 2 treatment reduced bitter amino acid content and changed VOCs profiles. The 1 H-NMR and GC-MS were combined to investigate the effects of different NaNO 2 concentration on the quality of Xuanwei ham. After adding NaNO 2 in the curing agents, the redness increased, the POV and TBARS values decreased, and N-dimethylnitrosamine was not detected. When the addition of NaNO 2 exceeded 90 mg/kg, the nitrite residue exceeded the acceptable range (<4 mg/kg). Saturated fatty acids (SFA) were the most abundant fatty acids (1918.01∼2877.02 mg/kg). After adding NaNO 2 , the content of SFA and polyunsaturated fatty acids (PUFA) decreased, but the content of monounsaturated fatty acids (MUFA) increased. Forty-four small molecular metabolites were detected, with the highest content of free amino acids (FAAs, 62.65∼75.79 mg/g). The amount of bitter amino acids was decreased, and the volatile compounds (VOCs) profile was altered by the addition of NaNO 2 . The content of aldehydes decreased while that of esters increased. These findings provide a theoretical basis for enhancing the quality control of Xuanwei ham.