Mechanical compaction of flour: the effect of storage temperature on dough rheological properties.

摘要

The effects of storage temperature, storage time, and compaction of compressed flour on functional and rheological properties of dough were investigated for flour milled from No. 1 Canadian Western Red Spring wheat. Untreated (loose) flour and flourthat had been mechanically compacted to a 55% volume reduction were stored for one year at 20, 30, and 40oC. An imitative rheological test (capillary rheometry) indicated that compaction of 75% extraction rate flour had a marked effect on the magnitudeof the flow behaviour index (n). This effect was not observed in 83% extraction rate flour. Storage time had a substantial effect on all samples, increasing the n values by 5-15%. A similar effect was observed for consistency coefficient. Alveograph andfarinograph results indicated that the main factor affecting the oxidation of compacted and loose flours during storage was the storage temperature. Compaction of flour appeared to have a slight mitigating effect on changes to alveograph curves during storage. Storage of flour up to 30oC caused changes in dough rheological parameters, indicating a dough strengthening effect. Storage of flour at 40oC resulted in tight inextensible dough that would be difficult to process in bakeries. Capillary extrusiontests confirmed that the flow behaviour index was noticeably affected by storage temperature.