Abstract: The volatile flavor compounds of fast-ripened Cheddar cheese slurry model fermented with Tibetan kefir and Cheddar cheese model fermented with commercial starter were extracted by solid phase micro-extraction (SPME) and identified by gas chromatography-mass spectrometry (GC-MS) and gas chromatography-olfactometry (GC-O). Results showed that the main volatile flavor components of Cheddar cheese model fermented with Tibetan kefir were alcohols and esters during its ripening. The number and amount of volatile flavor compounds in Cheddar cheese model fermented with Tibetan kefir were both higher than in Cheddar cheese model fermented with commercial starter. The volatile compounds which most significantly differed between two cheeses were esters. Sensory evaluation and flavor analysis showed that the number and amount of esters and alcohols in Cheddar cheese model fermented with Tibetan kefir were greater and it had a stronger flavor with fruity and wine aromas.

Key words: cheese model, gas chromatography-olfactometry (GC-O), solid phase micro-extraction (SPME), volatile flavor compounds