Wheat bread is an example of a product that can be enriched with bioactive ingredients. The objective of the research study was to assess the effect of enriching wheat bread with hazelnuts and walnuts of various maturity stages. Hazelnuts and walnuts were harvested in July and September. In the baking mix the ground nuts constituted 2 % and 7 % of the flour amount. The control sample was non-enriched bread. The bread was made using a direct method with yeast. Under the research study the following was calculated: dough efficiency, baking, total baking loss and bread efficiency. There were determined: bread volume, specific volume, crumb porosity, colour in the CIE L*a*b* system and texture parameters. Also determined were antioxidant properties of bread (using ABTS·+ , DPPH·, and FRAP methods), total content of polyphenolic compounds, profile and content of polyphenols using an UPLC-PDA-ESI-MS method. A three-way ANOVA was used to analyse the results. It was found that enriching the bread with nuts of different maturity stages impacted its physicochemical and antioxidant properties. The higher amount of nuts added, the higher the dough efficiency and the bread efficiency were. The control sample was characterised by the highest volume, and enriching the bread with nuts resulted in a reduction in its volume. The smallest volume was characterized by the bread enriched with unripe walnuts harvested in July. The crumb of this bread was characterised by the lowest L* value and it was the hardest. The type of nuts and their maturity stage had a significant effect on the antioxidant properties and content of polyphenols in bread. The values of those parameters decreased with the increasing maturity of the nuts added, and the breads enriched with walnuts were characterised by a significantly higher content of total polyphenols compared to the control sample and to those enriched with hazelnuts. Twelve compounds were identified in the profile of polyphenols of the breads tested.
wheat bread, nuts, maturity stage, enrichment, polyphenols