Characterization of the key odorants in kurut with aroma recombination and omission studies.

Kurut is a traditional acid-coagulated cheese from the northwest region of China. Using gas chromatography olfactometry and aroma extract dilution analysis, we identified 21 potent odorants from kurut within the flavor dilution factor range of 8 to 256. We developed a kurut matrix to determine the odor thresholds of key aroma compounds in kurut. The odor activity values of these 21 potent volatile compounds revealed that 18 were present at concentrations above their odor threshold values and therefore contributed to the overall aroma of kurut. The result of aroma recombinant experiments prepared by mixing the 18 most important odorants at the concentrations in which they occurred in kurut showed that the overall aroma profile of the recombinant sample was very similar to that of kurut. Omission experiments indicated that acids, furans, esters, and ketones were the most important volatile compounds in kurut. Some aroma compounds-such as butanoic acid, homofuraneol, ethyl hexanoate, and ethyl butanoate-play the most important roles in the overall flavor profile of kurut. Some odorants with a high flavor dilution factor, such as sulfur compounds, may have little effect. The study of key aroma compounds in kurut could provide important information for researching and developing traditional Chinese cheese products.