Changes in volatile sulfur compounds in strawberry puree during heating

Solid-phase microextraction coupled with gas chromatography/pulsed flame photometric detection was used to monitor methane thiol, hydrogen sulfide, sulfur dioxide, dimethyl sulfide, carbon disulfide, methyl thioacetate, dimethyl sulfide, methyl thiobutyrate, and dimethyl trisulfide after heating strawberry puree at 95 degrees C for 0, 0.5, 1.0, 1.5, 2.5, 4, and 10 min. After heating 10 min, dimethyl trisulfide increased from 0.11 to 0.41 ng/mL, and dimethyl disulfide decreased from 1.3 to 0.3 ng/mL. Concentrations of methyl thiobutyrate and methyl thioacetate were approximately 6 and 60 ng/mL, respectively, and essentially unaffected by heating. Dimethyl sulfide (cabbage aroma) was not detected in fresh puree but increased exponentially during heating, reaching a value of 500 ng/mL (100X its odor threshold) at 10 min. Dimethyl sulfide was the major sulfur aroma impact compound in heated strawberry puree and a major contributor to the flavor change associated with heated strawberry puree.