Improvement of the rate of substitution of wheat by rice in bread making by the use of xanthan gum: Technological and sensory properties

The aim of this study was to explore the possibilities of producing composite breads from blends of rice and wheat flours, with the addition of xanthan gum. The aim is to provide an effective and considerable substitute for wheat in bread making. Six formulations of rice (R) and wheat (B) flour blends were prepared in different proportions: 100%B, 50%R/50%B, 60%R/40%B, 65%R/35%B, 70%R/30%B, 85%R/15%B. The functional and rheological characteristics of the composite breads were evaluated and compared with those of 100% wheat bread, used as a reference. A constant percentage of xanthan gum (0.25%) was added to each mix. Samples containing 50%, 65% and 70% rice flour, in combination with xanthan gum, showed promising results in terms of volume, water loss, color and sensory acceptability.  The 50%R/50%B bread gave the best rheological results, with a volume of 1.7933cm3/g, closest to that of the control bread with a specific volume of 3.448cm3/g of wheat; its water loss was 8.9%, lower than that of the control bread (10%); and its color and honeycomb structure were similar to those of wheat. Sensory evaluation revealed that the 50%R/50%B bread was the most appreciated by panellists, achieving an acceptability rate of 80%. This study demonstrates the feasibility of replacing wheat with other cereals, such as rice, using xanthan gum to maintain excellent technological and sensory properties. These results suggest that rice could be appropriately incorporated into wheat flour, up to a substitution rate of 70%.