Bread wheat quality under limiting environmental conditions: II – Rheological properties of Lebanese wheat genotypes

Abstract

In the general framework of a program to improve the local production of common wheat by the Lebanese State, we have characterized the rheology of different bread wheat cultivars selected for their adaptation to semi-arid weather conditions. After a biochemical characterization [i.e. synthesis and accumulation of the major constituents of the grains (mainly storage proteins and starch)] of the plant material selected in a previous work, the main technological behavior of the flour that resulted from these grains and associated with bread-making properties was evaluated in the present study. Despite the selection of the plant material used in this study, the results demonstrate that environmental conditions inducing limitations in reserve accumulation [i.e. high gliadin content, very high level of polymerization/aggregation of polymeric prolamins, significant increase in the amylopectin/amylose ratio, modifications in the distribution of starch granules (A-type vs. B-type)] during grain filling affected the rheological behavior. The studied flours showed high wet and dry gluten contents, high Zeleny values, and a low gluten index value. They also showed high extensibility on the alveograph and extensograph and elevated dough strength on the farinograph, as well as great water absorption. Furthermore, flours of the studied cultivars did not express their optimal rheological potential in spite of their favorable glutenin subunit composition.

Keywords

• Bread wheat
• Semi-arid environments
• Technological quality
• Rheological behavior
• Limiting weather conditions
• Bread making properties