Physical properties of breads containing hydrocolloids stored at low temperature: II-Effect of freezing

摘要

Bread types such as dough samples (DB), semi-baked (SB) and full-baked (FB) breads were frozen stored for a week and further baked (DB or SB). Structure stabilizers such as xanthan (X), hydroxypropylmethylcellulose (HPMC), guar gum (GG) or locust bean gum (LB) were also added to the dough. Baking stage is important for bread quality after storage; additionally hydrocolloids provide stability in many frozen foods. Fresh bread samples were prepared for comparison. Yield in baked product, dough characteristics, specific volume, porosity, textural properties of both crumb/crust, moisture content of crumb/crust and finally crust thickness and colour were measured. Data grouping was performed using PCA analysis and correlations among the properties measured were found. X and LB addition resulted in the most stable dough, since strength and dough extensibility change during storage was low. Hydrocolloid stabilizers' (HS) influence on final bread characteristics was more pronounced in DB and SB breads. Crust moisture content was higher in SB breads, and it reached values 11-19% higher in control and galactomannan-containing breads than in DB respective samples. Bread specific volume was highly correlated to the crumb moisture content, to the crumb/crust textural characteristics and to the yield in the baked product. It was not correlated to crust moisture content and thickness. Porosity and bread colour were not correlated to any of the other properties. Bread type and HS selection are important factors for improving stability during storage.