Cereal Chem 68:105-107   |  VIEW ARTICLE

Frozen Bread Dough Ultrastructure as Affected by Duration of Frozen Storage and Freeze- Thaw Cycles.

P. T. Berglund, D. R. Shelton, and T. P. Freeman. Copyright 1991 by the American Association of Cereal Chemists, Inc. 

Cryogenic preparation of frozen bread dough permitted examination of changes in ultrastructure by low- temperature scanning electron microscopy (SEM). Doughs examined after mixing and frozen doughs, thawed during SEM preparation, exhibited a reticular pattern. After mixing and 24 hr frozen storage, starch granules appeared firmly embedded in the gluten network, which was mostly intact. Some starch granules exhibited internal damage and were more separated from the gluten matrix after 24 weeks of frozen storage and freeze-thaw cycles. When doughs were kept frozen during SEM preparation, the reticular pattern was not apparent. After 24 weeks frozen storage and freeze-thaw cycles, doughs that were kept forzen during SEM preparation had less free water distributed throughout the sample. In those doughs, less water appeared to be associated with the gluten matrix and starch. Patches of ice were observed in samples kept frozen during SEM preparation. The observed changes in ultrastructure may help explain the extended proof times and reduced loaf volumes of frozen bread dough.