Impact of frozen storage time on the volatile profile of wheat bread crumb.

The freezing of wheat bread before aroma analyses is a common practice in order to preserve loss of the volatile profile. However, the impact of the frozen storage time on the aroma profile has not been studied. For this purpose, the volatile profiles of wheat bread frozen for 1, 2 and 4weeks were analysed employing solvent extraction and static headspace methoologies with GC/MS. The results revealed that the freezing was effective to prevent the loss of volatiles during the first week. However, after two weeks, there was an increase of volatile compounds, probably generated by chemical reactions. Thus, a maximum of one week of frozen storage was recommended when using the solvent extraction methodology. When using the static headspace method, the samples should be analysed on the same day as preparation, since the extraction was surprisingly increased due to the starch retrogradation that occurred during freezing.