Yeast extracts weakened warmed-over flavor in surimi gels made from silver carp due to the masking effect by high concentrations of pyrazines and esters.

Warmed-over flavor (WOF) is an off-flavor in surimi gels. Yeast extract (YE) could improve the aroma properties of food. However, the effect of YE on the WOF in surimi gels and its mechanism was still unclear. In this study, aroma profiles, the composition of aroma compounds and aroma precursors, concentrations of WOF compounds, and thiobarbituric acid reactive substances (TBARS) of surimi gels with different amounts of YE were investigated by molecular sensory science and chromatographic techniques. Moreover, the effect of pyrazines and esters introduced by YE on WOF was also tested by sensory analysis. The addition of no less than 1% YE to surimi gels significantly weakened WOF. However, YE did not decrease the concentrations of WOF compounds and did not change the fatty acid composition and TBARS in surimi gels. Conversely, the addition of YE significantly increased the contents of free amino acids, N-containing compounds, and esters in surimi gels. The contents of total free amino acids, 2,6-dimethylpyrazine, and ethyl acetate in surimi gels with 2.5% YE were 1.5, 21, and 2.1 times higher than those in the control, respectively. Additionally, the sensory results of the spiked aroma models containing WOF compounds, 2,6-dimethylpyrazine, and esters showed that more than 9.4 µg/kg of 2,6-dimethylpyrazine with a baked-potato note and more than 6.1 µg/kg of ethyl acetate and 11.2 µg/kg of butyl acetate with a fruity note could significantly mask WOF. In conclusion, WOF in surimi gels could be masked by YE due to the high concentrations of pyrazines and esters. Practical Application: Yeast extracts could decrease the warmed-over flavor (WOF) due to the high concentrations of pyrazines (baked-potato note) and esters (fruity note). This finding extends the application of yeast extracts in the food industry. On the other hand, this study presents a reasonable solution for the reduction of WOF in surimi products.