April 16/Science Letter -- According to recent research published in the journal European Food Research and Technology, "Staling of breads baked in different ovens (microwave, infrared-microwave combination and conventional) was investigated with the help of mechanical (compression measurements), physicochemical (DSC, X-ray, FTIR) and rheological (RVA) methods. The effect of xanthan-guar gum blend addition on bread staling was also studied."

"Xanthan-guar gum blend at 0.5% concentration was used in bread formulation. The gums were mixed at equal concentrations to obtain the blend. After baking, the staling parameters of breads were monitored over five days storage. During storage, it was seen that hardness, retrogradation enthalpies, setback viscosity, crystallinity values and FTIR outputs related to starch retrogradation of bread samples increased, whereas FTIR outputs related to moisture content of samples decreased significantly with time. The hardness, retrogradation enthalpy, setback viscosity and crystallinity values of microwave-baked samples were found to be highest among other heating modes. Using IR-microwave combination heating made it possible to produce breads with similar staling degrees as conventionally baked ones in terms of retrogradation enthalpy and FTIR outputs related to starch retrogradation," wrote S.O. Ozkoc and colleagues, Middle East Technical University.

The researchers concluded, "Addition of xanthan-guar gum blend decreased hardness, retrogradation enthalpy and total mass crystallinity values of bread samples showing that staling was delayed."

Ozkoc and colleagues published their study in European Food Research and Technology ("Investigation of physicochemical properties of breads baked in microwave and infrared-microwave combination ovens during storage." European Food Research and Technology, 2009;228(6):883-893).

For additional information, contact G. Sumnu, Middle East Technical University, Dept. of Food Engineering, TR-06531 Ankara, Turkey.

From the April 27, 2009, Prepared Foods E-dition