Comparison of autoclave, microwave, IR and UV-C stabilization of whole wheat flour branny fractions upon the nutritional properties of whole wheat bread

In this study, whole wheat bread (WWB) prepared by whole wheat flour (WWF) which its branny fraction (35+/-1% w/w whole flour) previously was stabilized with different processes. Branny fractions obtained by milling of two different Bezostaja-1 wheat samples (medium and high strong) at 65+/-1% wheat flour extraction ratio. These fractions were stabilized using autoclave (AU), microwave (MW), infrared (IR) and ultraviolet-C (UV-C) methods. Then, WWF obtained by remixing of stabilized branny fraction (35+/-1% w/w) and wheat flour (65+/-1% w/w) of same wheat samples. Following this process, WWB was made from WWF. WWB were analyzed to determine their nutritional properties as crude protein, in vitro protein digestibility (IVPD), phytic acid content, total and HCl-extractable mineral concentrations, total phenolic content (TPC), antioxidant activity and total dietary fiber (TDF). While IVPD, TPC and antioxidant activity of WWB increased together with all stabilization methods, a significant (P<0.05) loss was observed on phytic acid content of the WWB. Especially, UV-C and IR treatments had positive effects on TPC and antioxidant activity. AU and MW stabilization methods increased total mineral and HCl-extractable minerals of WWB. As a result of this study, all stabilization processes had an improving effect on nutritional characteristic of WWB.