The effects of additives on dough rheological properties of pre-proofed frozen dough and baking quality of bread sticks

Scope and method of study. The effects of commercial dough conditioner (CDC) and methylcellulose (MC), glutathione (GSH) and dead yeast on dough rheological properties and baking quality of bread sticks made from pre-proofed frozen dough were investigated. The properties of frozen dough and baked bread sticks were studied as a function of storage time (1 day and up to 12 weeks). The rheological properties of a full formula dough were studied using Rheofermentometer, dynamic stress rheometer and texture analyzer. Phase separation of the dough was also studied using ultracentrifugation. Dough and bread structure were investigated using SEM and photo images. Starch gelatinization using enzymatic method and baking quality were determined.; Findings and conclusions. Rheofermentometer parameters showed significant correlations with baking quality and could be used to predict baking quality of bread sticks. Storage (G′) and loss (G′′) moduli obtained from dynamic rheological test of the dough showed the highest correlation with the total area of the extensibility test for the dough receiving a rest period of 26 min prior to testing (r = 0.678 at 0.05 Hz). The ratio of maximum resistance to extension (Rmax) to distance at maximum force (E) correlated with crust and crumb scores and crumb firmness but not with specific volume. The addition of MC and the mix of CDC and MC improved specific volume and crumb firmness of frozen dough. MC improved crust score of bread sticks made from hard red spring flour but not from hard red winter flour. Breadsticks containing dead yeast (heat treated) showed pale crust color, dark brown spots, blisters and dense grain in fresh and frozen dough. Freshly baked breadsticks (no frozen storage time) containing GSH showed no apparent change in crust and crumb color including crumb grain while small brown spots on the crust, and coarse and yellowish crumb were observed when the dough was frozen even for only one day. In conclusion, additives (MC and CDC+MC) could be used to improve dough properties and baking quality but could not prevent discoloration and brown spots in the crust at long period time of frozen dough (8–12 weeks). These defects were affected by GSH and dead yeast cell.