A Study on Staling Characteristics of Gluten-Free Breads Prepared with Chestnut and Rice Flours

The effects of chestnut flour and a xanthan-guar gum blend-DATEM mixture on staling of gluten-free rice breads baked in conventional and infrared-microwave combination ovens were studied. Staling properties of the bread were assessed using mechanical compression (TA), differential scanning calorimetry, X-ray diffraction, and fourier transform infrared spectroscopy (FT-IR). Hardness, moisture loss, and retrogradation enthalpy values for all bread samples increased significantly during storage. FT-IR spectra showed that the integrated area of peaks around 1,041 and 1,150 cm(-1) wave lengths, which are related to the structure of starch retrogradation, increased with storage time. The X-ray diffractograms of aged breads indicated a B-type structure with the appearance of peaks at around 17A degrees, 19.5A degrees, and 22A degrees. An additional peak at 24A degrees was observed in breads stored for longer periods. Higher values of hardness and lower moisture contents were obtained for breads baked in an infrared-microwave combination oven, but the use of infrared-microwave combination oven did not result in excessive hardness after storage. Retrogradation enthalpies and total crystallinity values of breads did not show significant differences with baking type.The replacement of rice flour with chestnut flour and addition of xanthan-guar gum blend-DATEM mixture in formulations significantly delayed staling of gluten-free breads by decreasing moisture loss, hardness, retrogradation enthalpy, and total mass crystallinity.