Gluten-free bread made with non-defatted ground walnuts: microstructural, technological, and nutritional properties

Abstract

Non-defatted walnuts are interesting for developing gluten-free (GF) bread because they contain bioactive compounds and high concentrations of fibre and polyunsaturated fatty acids (PUFAs). This study aimed to determine the effects of the addition of non-defatted ground walnuts (10%, 20%, and 30%) on the nutritional and technological quality of GF breads. Furthermore, control bread (formulation without ground walnuts) and bread with 20% walnuts were selected for microstructure and sensory evaluation. The addition of walnuts led to a significant increase in specific volume, affected crumb and crust colour and produced harder and crumblier crumbs. Despite these changes, the walnuts improved the nutritional and sensory properties of breads without affecting the starch gelatinisation or protein stabilising role (on air bubbles and lipid droplets). Lipid oxidation did not increase in breads containing walnuts at 10% and 20% level. These findings suggest that, even at high levels, non-defatted ground walnuts are a suitable ingredient for GF bakery products.