Effect of Microwave Assisted Baking on Quality of Rice Flour Bread

Abstract To develop gluten free bread, rice flour dough with the addition of whey protein concentrate (WPC, 0–6 g/100 g flour) was baked under three conditions – hot air baking (HA), microwave baking (MW) and microwave‐assisted hot air baking (HA‐MW). An increase in the WPC content increased the volume and the moisture content of the bread (P ≤ 0.05). The MW and HA‐MW methods increased the hardness of bread crumbs and the L* value of the bread crust (P ≤ 0.05). The estimated glycemic index (GI) of the HA bread was 80.34 ± 0.88. With the addition of 6 g WPC/100 g flour, the GI was reduced to 70.46 ± 1.70. By changing from HA to MW, the GI was further reduced to 61.67 ± 0.69. Without the addition of WPC, enthalpy of retrogradation (ΔH) of the freshly baked bread using MW was higher than from HA and HA‐MW. The enthalpy tended to increase with increased storage time. Practical Applications Microwave could increase the heating rate during baking and affect the protein‐starch matrix in gluten free bread made from rice flour. Consequently, bread made using the microwave baking method has low starch digestibility and a high enthalpy of retrogradation with increased volume. Therefore, MW with the addition of whey protein concentrate is recommended to develop crustless, gluten‐free bread with a reduced glycemic index, which is good for people who suffer from obesity, diabetes and celiac disease.